Syndromes and disorders associated with mental retardation
http://www.100md.com
《美国医学杂志》
Pediatrics and Human Development, Michigan State University College of Human Medicine, MSU/Kalamazoo Center for Medical Studies, Kalamazoo, Michigan, USA
Abstract
This article reviews selective comments on the concept of Mental Retardation (MR) in adolescents. Issues covered include the definition, prevalence, and differential diagnosis of MR. Some of the syndromes and disorders associated with MR in the adolescents are also considered with emphasis on the behavioral concerns that may be present in this age group. Finally, concepts of management by the clinician are reviewed. It is recommended that health care professionals caring for adolescents with MR should help these youths maximize their potential as human beings, helping them achieve meaningful functioning in adulthood.
Keywords: Mental retardation; Cerebral palsy; Autism; Down syndrome; Fragile X syndrome
Various terms are used in the West for Mental Retardation, including mental subnormality, mental deficiency, feeble mindedness (late 19th Century term), and mental disability. [1],[2] The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, (DSM-IV-TR, 2000) [3] defines MR as a central nervous system dysfunction producing an IQ below 70; this results in significant deficiencies in two or more life skills, such as self-direction, academic skills, social skills, communication, health, and work. Five subdivisions are identified: mild (IQ 50/55 to 69), moderate (35/40 - 50/55), severe (20/25 - 35/40), profound (under 30/25) and severity unspecified (suspected, but not testable).[3]
The American Association on Mental Retardation (AAMR) looks at MR by using a concept of both a low average intelligence with impairment of adaptive functioning in two or more life skills areas: academics, work, leisure, functional, and health/safety.[4] This AAMR approach uses an MR classification that looks at patterns and intensity of support that the individual needs: intermediate , limited , intensive , and pervasive .[5] Its environmental context is consistent with the vision of the World Health Organization International.
The term, d evelopmental disability , was developed in the United States during the 1960s and it referred to functional impairment without incorporating actual etiology.[1] From a legal perspective, the government of the United States places MR in the category of a developmental disability, as per Public Law 95 - 602 (1978). In this view, developmental disability is a disability due to severe mental or physical impairment, noted before age 22. It is probably lifelong and causes significant impairment in three or more areas of functioning; this impairment results in the need for lifelong, extended care utilizing services from various disciplines. By law, developmental disability does not include the mild form of MR. Clinicians in Europe do not use the term MR, preferring such terms as intellectual disability or learning disability.[1]
Prevalence
Prevalence Figure ures for MR vary depending upon the definition used, methods utilized to identify MR, and what population is being considered. [6],[7],[8] If one uses the DSM-IV definition for MR, 3% of the population has mild MR, 0.4% has moderate, and 0.1% has severe MR. The prevalence for severe MR has been the same in the United States since the 1940s; however, as malnutrition has improved in various parts of the world, MR has become less common than it has been over thousands of years.[9] Study of children in American school systems looking at those eligible for government-funded services note that 1.14% of American school children meet the criteria for MR.[5],[8] Causes of MR can change over time as understanding and technology changes. For example, the reduction of MR due to congenital hypothyroidism or phenylketonuria in the United States has been balanced by MR due to the increase in drug use during pregnancy and the greater survival of micro-premature infants.[8]
Differential diagnosis
Over half of the patients with autism or cerebral palsy also have MR, and the finding of MR can confuse the nature of these conditions or others, such as communication disorders.[8] Sometimes mild MR is confused with borderline MR, a condition noted in about 7% of the general population. MR may be misdiagnosed as dementia in which there is a major reduction in memory function and other cognitive deficits from previous levels. A number of mental health conditions such as mood disorders, stereotypic movement disorders and attention-deficit/hyperactivity disorder (ADHD) may occur with MR; dementia caused by head trauma may simulate MR.[3],[10]
Syndromes and Disorders Associated with MR in Adolescents
MR is associated with various syndromes, disorders, and conditions.[1],[11],[12] table1 provides a partial list of these associations and this paper comments on some of these syndromes, with emphasis on the emotional or behavioral aspects complicating the care for these children when they become adolescents. Features of these syndromes may change as the child becomes an adolescent; for example, in the Angelman syndrome, a child is noted to have severe developmental delay with epilepsy; as an adolescent, this individual is often seen as smiling and having an uncontrolled laughter along with an ataxic gait. Intractable, self-injurious behavior is characteristic for the Lesch- Nyhan Syndrome.
Autism
In Autism (Pervasive Developmental Disorders) MR can noted in 80%, though a wide variability is noted.[3],[11],[12] The etiology is not known in most cases, and the onset of puberty is usually normal; its incidence is about 4 per 10,000. Interpersonal relationships are limited and adolescents with autism tend to be withdrawn from family and peers. Violent and self-destructive behavior can occur and the behavioral issues can be complicated by the presence of epilepsy.
Cerebral Palsy
Cerebral palsy is noted in 2 per 1000 live births and is related to damage from the pre- or peri-natal period.[13] It may be associated with a wide range of IQ (from very low to very high) and with a wide range of medical problems including spasticity, orthopedic defects, epilepsy, and others. Behavioral problems may be related to the level of MR, drooling, reliance on others for care, and spasticity. Precocious puberty can occur, though it is usually normal in onset.
Down Syndrome
Down syndrome is a disorder due to trisomy of chromosome 21 and presents in 1 in every 700 to 800 births; about 3% have a translocation of chromosome 21 and some are mosaic.[14] MR is variable, though usually in the moderate range (50-60 IQ). Classic features of Down syndrome are noted in table2.[14],[15],[16],[17] Nearly 20% develop behavioral problems, including attention-deficit/hyperactivity disorder (ADHD), depression, expressive language deficiency, aggressive behavior, and autism.[14],[18] The majority of youth with Down Syndrome develop a self-talk process that sometimes is confused with psychosis.
Children with Down syndrome have a high risk of secondary pulmonary hypertension in high pressure left to right shunts if not treated with surgery; surgical correction before 6 months of age usually prevents the development of secondary pulmonary hypertension when they become adolescents and young adults.[19] They need subacute bacterial prophylaxis for cardiac valve insufficiency.[14] The onset of puberty is usually normal, though hypogonadism is noted with increased incidence in the male. Males do not usually reproduce, but females with Down syndrome have an increased risk for having a child with Down syndrome.[14],[16]
Fragile X Syndrome
The Fragile X Syndrome is the most common type of the X-linked MR syndromes with an incidence of 1 in 1000 to 1400 males. However, the phenotype may not be recognized until the adolescent years. One in 1000 females are carriers and 1 in 2500 to 3000 females are affected. It is caused by an expanded trinucleotide area in the Fragile X gene on the X chromosome.[14] It should be considered in a child or adolescent with MR who has no established etiology and no overt structural abnormalities.[9] The IQ is variable, though typically is 30 to 55. There may be an IQ decline as they fall beyond same-age peers.
Major problems in adolescence relate to cardiac disorders and behavioral problems table3. Male adolescents with Fragile X Syndrome may develop aggressive behavior with hyperactivity and severe temper tantrums; they may have autism-like behavior with gaze aversion.[20] Their speech is varied and may be high-pitched, jocular, and "retarded." A perseverative speech pattern may be noted. Females who are carriers may be shy and demonstrate social phobia and depression. Females with overt Fragile X Syndrome may have the same overall features as males.
Meningomyelocele
Meningomyelocele is a neural tube defect with origins in early development of the fetus with an incidence of 4 per 10,000.[11],[12] Neuromuscular dysfunction may be severe, including paralysis and being brace- or wheel-chair bound. There can also be ventriculoperitoneal shunt problems, chronic low weight, renal dysfunction, constipation, urinary tract infections, arthritis, chronic pulmonary dysfunction and other medical problems. Puberty may be at a normal age or be precocious. The IQ is usually 80 to 90, though 25% have an MR range. Adjustment during adolescence may be made difficult by these problems as well as urine or bowel incontinence, learning disorders, sexual dysfunction and others. Prenatal folic acid supplementation has reduced the incidence of this condition.
Neurofibromatosis
This is an autosomal dominant disorder due to NF1 gene mutations on chromosome 17.[14],[21],[22] The risk to a child of a parent with neurofibromatosis is 50% and puberty can be at a normal time or be early. table4 lists diagnostic criteria for neurofibromatosis.[14],[21],[22] The adolescent may have a wide range of problems including hypertension, plexiform neurofibromas, scoliosis, central nervous system tumors, headaches, constipation, and many others. The incidence is one in 3000 and the average IQ is nearly 90, though as many as 5% are in the MR range. Behavioral disorders include speech dysfunction, ADHD, learning disorders and problems related to their potential visual anomalies.
Prader-Willi syndrome More Details
This classic syndrome is caused by insufficiency of chromosome 15 that is inherited from the father.[14] The incidence is one in 10,000 and the IQ is usually 40 to 60, with a range of 20 to 80. Hypogonadism, short stature (with small hands and small feet), and Obesity (with hyperphagia, food foraging binges, and bizarre eating habits) are classic features of the Prader-Willi syndrome.[23] The obesity can become morbid and life-threatening, with the development of sleep apnea, hypertension, diabetes mellitus, and thrombophlebitis. They have characteristic facies (narrow bifrontal diameter, palpebal fissures that are almond-shaped, mouth that is downturned, and skin characterized by albinoidism. The onset of puberty is usually delayed and complicated by a small penis and cryptorchidism in males; females have reduced secondary sexual development and amenorrhea. Other problems include osteoporosis and scoliosis. Adolescents with Prader-Willi Syndrome have an increased incidence of behavioral problems complicated by their many defects; ADHD, compulsivity, temper tantrums, and skin picking are increased. Males with this syndrome are sterile, while females have a 50% risk for producing an offspring with the Angelman syndrome.
Velocardiofacial Syndrome (VCFS)
VCFS is caused by a miscorrelation of chromosome 22 and is typically identified in childhood. It has various other names including 22q deletion syndrome, DiGeorge syndrome, Shprintzen syndrome, and occasionally, CATCH-22.[14] It involves thymus abnormalities (agenesis or hypoplasia), ear deformities (hypoplasia of the external ear and the canal), cleft palate, cardiac defects and short stature. During the adolescent years, hypocalcemia becomes common, and thus, annual calcium screening is recommended in these patients when they become adolescents. The MR is usually mild and the adolescents may have learning disorders. If an adolescent with VCFS becomes pregnant, her baby has a 50% chance of having this same syndrome. Youth with VCFS have an increased risk for behavioral disorders (including schizophrenia and depression, and bipolar disorder) and should be monitored for mental health problems.[24],[25]
Williams Syndrome
This syndrome is due to a micro deletion at chromosome 7 (7q11.23) and leads to a number of anomalies table5.[14],[15],[19],[26] The incidence is 1 in 20,000 live births and a patient with Williams syndrome has a 50% chance of having an offspring with this syndrome. Most have mild MR, though the IQ range is 40 to 80. The short stature and increased early puberty gets the adolescent years off to a potentially difficult start. There is an increased incidence of enuresis, limited perceptual-motor skills, anxiety disorders, ADHD, and immaturity. Adolescents tend to be loquacious (cocktail, talkative personality) with inappropriate friendliness, leading to increased abuse by predators.[14],[19] These youths tend to have musical abilities which can be used to improve their self-esteem.
Psychosocial perspectives on management
MR is characterized by significant delays in intellectual functioning. Adolescents diagnosed with MR have serious developmental delays in their intellectual, social and adaptive functioning. Cognitive deficits become more apparent when they are required to engage in academic activities. Youth who are diagnosed with mild to moderate MR can be trained to function at a semi- independent level but will require some support through out their lives. Youths diagnosed with severe to profound MR will always require care. The most difficult group to manage and support are those individuals who are not mentally retarded but do not have average levels of intellectual functioning (IQ scores 70 - 85). These youths are at risk of victimization; young women do not have the intellectual capacity to learn how to prevent rape; young men often get in trouble with authorities because they are easily led astray by their cognitively superior peers.
Adolescents with MR or mental disorders of a severe nature are usually unable to function without moderate to intense supervision and care. Because they rarely function independently, they are not subject to many of the psychosocial risks of their higher functioning peers. They are, however, subject to an increased risk of being physically or sexually abused or neglected. Adolescents with moderate to mild MR or mental disorders are more autonomous and are at risk of all the psychosocial hazards that their non impaired adolescent peers face.
Externalizing Behavior Problems
Adolescents with severe MR may exhibit self stimulatory behavior (rocking, making noises, masturbating, chewing on body parts or inanimate objects, hand flapping, moving of limbs, etc.). They may also engage in self injurious behavior and exhibit mild to severe tantrums. Efforts of care-givers should be directed to minimize the youth's ability to inflict self harm. These youths should be provided with non-harmful stimulating toys and objects and given a safe place with plenty of room and comfortable clothing to accommodate movement.
Adolescents with moderate MR may engage in the same behaviors to a greater or lesser degree. These youth may also become aggressive to others, engage in inappropriate sexual touching and use other inappropriate language at inopportune times. These youth will benefit from limited access to situations where they are not being monitored/supervised. They will need repeated reminders to engage in appropriate behaviors. Parents and care givers should be reminded that although these adolescents may not have
Abstract reasoning to think through their behaviors and resulting consequences, they do have concrete thinking abilities and can learn right from wrong. Because of this, supervision is needed to anticipate problems and help the adolescent make healthy decisions.
Youths with mild MR are at the highest risk of engaging in high risk behavior, becoming victims of physical, sexual and mental abuse. Because they generally have greater autonomy and live independently as they become adults, they have more opportunities to get into trouble. They often are the patsies and prey of smarter individuals who can easily talk them into engaging in high risk behaviors. Some of them often do not have the ability to think before they act without prompting and get caught when committing a crime or anti-social act. They are unable to think fast enough to tell a convincing lie to escape trouble. Because they lack the ability to anticipate what might happen next, and are generally very susceptible to the emotional context of a situation, they react to that emotion and escalate problem.
Caregivers must work very hard to enroll these youth in programs that teach prosocial behavior and problem- solving skills. They need to be surrounded by advocates who help them and come to their aid when they get into trouble. Physicians need to encourage parents and caregivers to constantly and repeatedly teach survival skills to these youth.
Special Consideration for Adolescent Depression and Suicide
Depressive disorders, which include major depressive disorder (unipolar depression), dysthymic disorder (chronic, mild depression), and bipolar disorder (manic-depression), can have far-reaching effects on the functioning and adjustment of young people. Among adolescents, depressive disorders confer an increased risk for illness and interpersonal and psychosocial difficulties that persist long after the depressive episode is resolved; in adolescents there is also an increased risk for substance abuse and suicidal behavior
Adolescents with depression may have difficulty in properly identifying and describing their internal emotional or mood states. For example, instead of communicating how bad they feel, they may act out and be irritable toward others which may be interpreted simply as misbehavior or disobedience. Research has found that parents are even less likely to identify major depression in their adolescents than are the adolescents themselves. These factors are especially true for adolescents with limited cognitive functioning.
Suicidal risk is also very high among these youths because of their limited cognitive functioning, especially the absence of
Abstract and futuristic thinking. When an adolescent with mild to moderate MR expresses suicidal tendency the physician and all care givers must directly and clearly tell the youth that that is unacceptable and inappropriate behavior. They must then help the adolescent clearly identify reasons to live and develop a concise and simple plan to live. This should include who the adolescent is to contact when he or she feels like wanting to hurt him or herself. It is essential that physicians do not ignore the risks of not detecting and treating depression in this group of youth. Because these youth generally have slowed thinking and response times to stimuli in the environment, the physician must take this into account with prescribing medications.
Risk of Academic Failure
Adolescents with mild to moderate MR are at risk of experiencing academic problems and even failure. These youths often do not qualify for Special Education services because their academic functioning often commensurates with their intellectual functioning. Extra or supportive services are frequently not available to these youth. Adolescents who struggle in school are at risk of dropping out of school and all the other associated problems. Physicians should encourage parents to enter their adolescents in skill training programs, and/or to provide extra tutoring and encouragement to learn.
CONCLUSION
0Adolescents with MR are at risk of a wide range of psychosocial problems. It is important that physician recognize that depending on the particular syndrome, these youths will experience various forms and levels of problems and require various levels of intervention to survive and succeed. Youth with mild forms of MR can learn to be independent with support and encouragement.
References
1. Greydanus DE, Bhave S. The Mentally-Challenged Adolescent. Recent Advances in Pediatrics, Kashmir, India, In Press, 2005
2. Wolraich M. "MR" In DE Greydanus and ML Wolraich, eds. Behavioral Pediatrics, NY; Springer-Verlag, 1992; 22: 314-323.
3. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th edn. Text Revision. Washington DC; American Psychiatric Association "MR", 2000; 41-49.
4. Luckasson R, Coulter D, Polloway EA et al. MR: Definition, Classification, and Systems of Supports , 10th edn. Washington DC; American Association on MR, 2002.
5. Carey JC. Genetic aspects of developmental disabilities In Rudolph, AM Rudolph, eds. Rudolph's Pediatrics. 21st edn. NY; McGraw Hill Med Pub Div, 2003; 779-782.
6. Leonard H, Wen X. The epidemiology of MR: challenges and opportunities in the new millennium. Ment Retard Dev Disabil Res Rev 2002; 8 : 117-134.
7. Roeleveld N, Zielhuis GA, Gabre'λls F. The prevalence of MR. A critical review of recent literature. Dev Med Child Neurol 1997; 39 : 125-132.
8. Shapiro BK, Batshaw ML. "MR". In RE Behrman, RM Kliegman, HS Junson, eds. Nelson Textbook of Pediatrics , 17th edn. Philadelphia; Saunders, 2004; 138-143.
9. Curry CJ. Rational evaluation of the adolescent with MR. Adolesc Med 2002; 13 : 331-343.
10. Lee P, Moss S, Friedlander R et al. Early-onset schizophrenia in children with MR. diagnostic reliability and stability of clinical features. J Am Acad Child Adolesc Psychiatry 2003; 42 : 162-169.
11. Brier NM. "MR" In SB Friedman, M Fisher, SK Schonberg, eds. Comprehensive Adult Health Care . St. Louis, MO; Quality Med Pub. Inc. 1992; 103 : 824-829.
12. Rauh JL. "Mentally Retarded Youth" In McAnarany, RE Kreipe, DP Orr, GD Comeric, eds. Textbook of Adol Med . Phildelphia; WB Saunders Company, 1992; 31:229-232.
13. Wollack JB, Nichter CA. "Cerebral palsy" In CD Rudolph, AM Rudolph, eds. Rudolph's Pediatrics. 21st edn. NY; McGraw-Hill Medical Publishing Div 2003; 25.5.1: 2197-2202.
14. Toriello HV. Genetics in adolescent medicine. In DE Greydanus, DR Patel, HD Pratt, eds. Essential Adolescent Medicine. NY; McGraw-Hill Medical Publishers, 2005; 21: 455-473.
15. Greydanus DE. "Down Syndrone, Williams Syndrome." In AD Hofmann, DE Greydanus. Adolescent Medicine, 3rd edn. Stanford; CT. Appleton-Lange, 1997; 451.
16. Roizen NJ. Medical care and monitoring for the adolescent with Down Syndrome. Adolesc Med 2002; 13 : 345-358.
17. Roizen NJ, Patterson D. Down syndrome. Lancet 2003; 361: 1281.
18. Merrick J, Kandel I, Vardi G. Adolescents with Down syndrome. Int J Adolesc Med Health 2004; 16 : 13-19.
19. Luckstead EF, Cardiovascular Disorders, Essential Adolescent Medicine. DE Greydanus, DR Patel, HD Pratt eds. NY; McGraw-Hill Medical Publishers, 2005; 9: 125-152.
20. Hagerman RJ, Cronister A, eds. Fragile X Syndrome: Diagnosis, Treatment and Research. 2nd edn. Baltimore, MD; Johns Hopkins University Press, 1996.
21. Gutmann DH, Aylsworth A, Carey J et al. The diagnostic evaluation and multidisciplinary management of neurofibromatosis 1 and neurofibromatosis 2. JAMA 1997;278 : 51.
22. Dahan D, Fenichel G, El-Said R. Neurocutaneous syndromes. Adol Med 2002; 13 : 495-509.
23. Goldstone AP. Prader-Willi syndrome: advances in genetics, pathophysiology, and treatment. Trends Endocrinol Metab 2004; 15 : 12.
24. Emanuel BS, McDonald-McGinn D, Saitta SC et al . The 22q11.2 deletion syndrome. Adv Pediatr 2001; 48: 39.
25. Lin RJ, Cherry A, Bangs CD, Hoyme HE. FISHing for answers: The use of molecular cytogenetic technizues in adolescent medicine practice. Adol Med 2002; 13 : 309-310.
26. Committee on Genetics. American Academy of Pediatrics. Health care supervision for children with Williams Syndrome. Pediatrics 2001; 107 : 1192-1204.(Greydanus Donald E, Pratt)
Abstract
This article reviews selective comments on the concept of Mental Retardation (MR) in adolescents. Issues covered include the definition, prevalence, and differential diagnosis of MR. Some of the syndromes and disorders associated with MR in the adolescents are also considered with emphasis on the behavioral concerns that may be present in this age group. Finally, concepts of management by the clinician are reviewed. It is recommended that health care professionals caring for adolescents with MR should help these youths maximize their potential as human beings, helping them achieve meaningful functioning in adulthood.
Keywords: Mental retardation; Cerebral palsy; Autism; Down syndrome; Fragile X syndrome
Various terms are used in the West for Mental Retardation, including mental subnormality, mental deficiency, feeble mindedness (late 19th Century term), and mental disability. [1],[2] The American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders, (DSM-IV-TR, 2000) [3] defines MR as a central nervous system dysfunction producing an IQ below 70; this results in significant deficiencies in two or more life skills, such as self-direction, academic skills, social skills, communication, health, and work. Five subdivisions are identified: mild (IQ 50/55 to 69), moderate (35/40 - 50/55), severe (20/25 - 35/40), profound (under 30/25) and severity unspecified (suspected, but not testable).[3]
The American Association on Mental Retardation (AAMR) looks at MR by using a concept of both a low average intelligence with impairment of adaptive functioning in two or more life skills areas: academics, work, leisure, functional, and health/safety.[4] This AAMR approach uses an MR classification that looks at patterns and intensity of support that the individual needs: intermediate , limited , intensive , and pervasive .[5] Its environmental context is consistent with the vision of the World Health Organization International.
The term, d evelopmental disability , was developed in the United States during the 1960s and it referred to functional impairment without incorporating actual etiology.[1] From a legal perspective, the government of the United States places MR in the category of a developmental disability, as per Public Law 95 - 602 (1978). In this view, developmental disability is a disability due to severe mental or physical impairment, noted before age 22. It is probably lifelong and causes significant impairment in three or more areas of functioning; this impairment results in the need for lifelong, extended care utilizing services from various disciplines. By law, developmental disability does not include the mild form of MR. Clinicians in Europe do not use the term MR, preferring such terms as intellectual disability or learning disability.[1]
Prevalence
Prevalence Figure ures for MR vary depending upon the definition used, methods utilized to identify MR, and what population is being considered. [6],[7],[8] If one uses the DSM-IV definition for MR, 3% of the population has mild MR, 0.4% has moderate, and 0.1% has severe MR. The prevalence for severe MR has been the same in the United States since the 1940s; however, as malnutrition has improved in various parts of the world, MR has become less common than it has been over thousands of years.[9] Study of children in American school systems looking at those eligible for government-funded services note that 1.14% of American school children meet the criteria for MR.[5],[8] Causes of MR can change over time as understanding and technology changes. For example, the reduction of MR due to congenital hypothyroidism or phenylketonuria in the United States has been balanced by MR due to the increase in drug use during pregnancy and the greater survival of micro-premature infants.[8]
Differential diagnosis
Over half of the patients with autism or cerebral palsy also have MR, and the finding of MR can confuse the nature of these conditions or others, such as communication disorders.[8] Sometimes mild MR is confused with borderline MR, a condition noted in about 7% of the general population. MR may be misdiagnosed as dementia in which there is a major reduction in memory function and other cognitive deficits from previous levels. A number of mental health conditions such as mood disorders, stereotypic movement disorders and attention-deficit/hyperactivity disorder (ADHD) may occur with MR; dementia caused by head trauma may simulate MR.[3],[10]
Syndromes and Disorders Associated with MR in Adolescents
MR is associated with various syndromes, disorders, and conditions.[1],[11],[12] table1 provides a partial list of these associations and this paper comments on some of these syndromes, with emphasis on the emotional or behavioral aspects complicating the care for these children when they become adolescents. Features of these syndromes may change as the child becomes an adolescent; for example, in the Angelman syndrome, a child is noted to have severe developmental delay with epilepsy; as an adolescent, this individual is often seen as smiling and having an uncontrolled laughter along with an ataxic gait. Intractable, self-injurious behavior is characteristic for the Lesch- Nyhan Syndrome.
Autism
In Autism (Pervasive Developmental Disorders) MR can noted in 80%, though a wide variability is noted.[3],[11],[12] The etiology is not known in most cases, and the onset of puberty is usually normal; its incidence is about 4 per 10,000. Interpersonal relationships are limited and adolescents with autism tend to be withdrawn from family and peers. Violent and self-destructive behavior can occur and the behavioral issues can be complicated by the presence of epilepsy.
Cerebral Palsy
Cerebral palsy is noted in 2 per 1000 live births and is related to damage from the pre- or peri-natal period.[13] It may be associated with a wide range of IQ (from very low to very high) and with a wide range of medical problems including spasticity, orthopedic defects, epilepsy, and others. Behavioral problems may be related to the level of MR, drooling, reliance on others for care, and spasticity. Precocious puberty can occur, though it is usually normal in onset.
Down Syndrome
Down syndrome is a disorder due to trisomy of chromosome 21 and presents in 1 in every 700 to 800 births; about 3% have a translocation of chromosome 21 and some are mosaic.[14] MR is variable, though usually in the moderate range (50-60 IQ). Classic features of Down syndrome are noted in table2.[14],[15],[16],[17] Nearly 20% develop behavioral problems, including attention-deficit/hyperactivity disorder (ADHD), depression, expressive language deficiency, aggressive behavior, and autism.[14],[18] The majority of youth with Down Syndrome develop a self-talk process that sometimes is confused with psychosis.
Children with Down syndrome have a high risk of secondary pulmonary hypertension in high pressure left to right shunts if not treated with surgery; surgical correction before 6 months of age usually prevents the development of secondary pulmonary hypertension when they become adolescents and young adults.[19] They need subacute bacterial prophylaxis for cardiac valve insufficiency.[14] The onset of puberty is usually normal, though hypogonadism is noted with increased incidence in the male. Males do not usually reproduce, but females with Down syndrome have an increased risk for having a child with Down syndrome.[14],[16]
Fragile X Syndrome
The Fragile X Syndrome is the most common type of the X-linked MR syndromes with an incidence of 1 in 1000 to 1400 males. However, the phenotype may not be recognized until the adolescent years. One in 1000 females are carriers and 1 in 2500 to 3000 females are affected. It is caused by an expanded trinucleotide area in the Fragile X gene on the X chromosome.[14] It should be considered in a child or adolescent with MR who has no established etiology and no overt structural abnormalities.[9] The IQ is variable, though typically is 30 to 55. There may be an IQ decline as they fall beyond same-age peers.
Major problems in adolescence relate to cardiac disorders and behavioral problems table3. Male adolescents with Fragile X Syndrome may develop aggressive behavior with hyperactivity and severe temper tantrums; they may have autism-like behavior with gaze aversion.[20] Their speech is varied and may be high-pitched, jocular, and "retarded." A perseverative speech pattern may be noted. Females who are carriers may be shy and demonstrate social phobia and depression. Females with overt Fragile X Syndrome may have the same overall features as males.
Meningomyelocele
Meningomyelocele is a neural tube defect with origins in early development of the fetus with an incidence of 4 per 10,000.[11],[12] Neuromuscular dysfunction may be severe, including paralysis and being brace- or wheel-chair bound. There can also be ventriculoperitoneal shunt problems, chronic low weight, renal dysfunction, constipation, urinary tract infections, arthritis, chronic pulmonary dysfunction and other medical problems. Puberty may be at a normal age or be precocious. The IQ is usually 80 to 90, though 25% have an MR range. Adjustment during adolescence may be made difficult by these problems as well as urine or bowel incontinence, learning disorders, sexual dysfunction and others. Prenatal folic acid supplementation has reduced the incidence of this condition.
Neurofibromatosis
This is an autosomal dominant disorder due to NF1 gene mutations on chromosome 17.[14],[21],[22] The risk to a child of a parent with neurofibromatosis is 50% and puberty can be at a normal time or be early. table4 lists diagnostic criteria for neurofibromatosis.[14],[21],[22] The adolescent may have a wide range of problems including hypertension, plexiform neurofibromas, scoliosis, central nervous system tumors, headaches, constipation, and many others. The incidence is one in 3000 and the average IQ is nearly 90, though as many as 5% are in the MR range. Behavioral disorders include speech dysfunction, ADHD, learning disorders and problems related to their potential visual anomalies.
Prader-Willi syndrome More Details
This classic syndrome is caused by insufficiency of chromosome 15 that is inherited from the father.[14] The incidence is one in 10,000 and the IQ is usually 40 to 60, with a range of 20 to 80. Hypogonadism, short stature (with small hands and small feet), and Obesity (with hyperphagia, food foraging binges, and bizarre eating habits) are classic features of the Prader-Willi syndrome.[23] The obesity can become morbid and life-threatening, with the development of sleep apnea, hypertension, diabetes mellitus, and thrombophlebitis. They have characteristic facies (narrow bifrontal diameter, palpebal fissures that are almond-shaped, mouth that is downturned, and skin characterized by albinoidism. The onset of puberty is usually delayed and complicated by a small penis and cryptorchidism in males; females have reduced secondary sexual development and amenorrhea. Other problems include osteoporosis and scoliosis. Adolescents with Prader-Willi Syndrome have an increased incidence of behavioral problems complicated by their many defects; ADHD, compulsivity, temper tantrums, and skin picking are increased. Males with this syndrome are sterile, while females have a 50% risk for producing an offspring with the Angelman syndrome.
Velocardiofacial Syndrome (VCFS)
VCFS is caused by a miscorrelation of chromosome 22 and is typically identified in childhood. It has various other names including 22q deletion syndrome, DiGeorge syndrome, Shprintzen syndrome, and occasionally, CATCH-22.[14] It involves thymus abnormalities (agenesis or hypoplasia), ear deformities (hypoplasia of the external ear and the canal), cleft palate, cardiac defects and short stature. During the adolescent years, hypocalcemia becomes common, and thus, annual calcium screening is recommended in these patients when they become adolescents. The MR is usually mild and the adolescents may have learning disorders. If an adolescent with VCFS becomes pregnant, her baby has a 50% chance of having this same syndrome. Youth with VCFS have an increased risk for behavioral disorders (including schizophrenia and depression, and bipolar disorder) and should be monitored for mental health problems.[24],[25]
Williams Syndrome
This syndrome is due to a micro deletion at chromosome 7 (7q11.23) and leads to a number of anomalies table5.[14],[15],[19],[26] The incidence is 1 in 20,000 live births and a patient with Williams syndrome has a 50% chance of having an offspring with this syndrome. Most have mild MR, though the IQ range is 40 to 80. The short stature and increased early puberty gets the adolescent years off to a potentially difficult start. There is an increased incidence of enuresis, limited perceptual-motor skills, anxiety disorders, ADHD, and immaturity. Adolescents tend to be loquacious (cocktail, talkative personality) with inappropriate friendliness, leading to increased abuse by predators.[14],[19] These youths tend to have musical abilities which can be used to improve their self-esteem.
Psychosocial perspectives on management
MR is characterized by significant delays in intellectual functioning. Adolescents diagnosed with MR have serious developmental delays in their intellectual, social and adaptive functioning. Cognitive deficits become more apparent when they are required to engage in academic activities. Youth who are diagnosed with mild to moderate MR can be trained to function at a semi- independent level but will require some support through out their lives. Youths diagnosed with severe to profound MR will always require care. The most difficult group to manage and support are those individuals who are not mentally retarded but do not have average levels of intellectual functioning (IQ scores 70 - 85). These youths are at risk of victimization; young women do not have the intellectual capacity to learn how to prevent rape; young men often get in trouble with authorities because they are easily led astray by their cognitively superior peers.
Adolescents with MR or mental disorders of a severe nature are usually unable to function without moderate to intense supervision and care. Because they rarely function independently, they are not subject to many of the psychosocial risks of their higher functioning peers. They are, however, subject to an increased risk of being physically or sexually abused or neglected. Adolescents with moderate to mild MR or mental disorders are more autonomous and are at risk of all the psychosocial hazards that their non impaired adolescent peers face.
Externalizing Behavior Problems
Adolescents with severe MR may exhibit self stimulatory behavior (rocking, making noises, masturbating, chewing on body parts or inanimate objects, hand flapping, moving of limbs, etc.). They may also engage in self injurious behavior and exhibit mild to severe tantrums. Efforts of care-givers should be directed to minimize the youth's ability to inflict self harm. These youths should be provided with non-harmful stimulating toys and objects and given a safe place with plenty of room and comfortable clothing to accommodate movement.
Adolescents with moderate MR may engage in the same behaviors to a greater or lesser degree. These youth may also become aggressive to others, engage in inappropriate sexual touching and use other inappropriate language at inopportune times. These youth will benefit from limited access to situations where they are not being monitored/supervised. They will need repeated reminders to engage in appropriate behaviors. Parents and care givers should be reminded that although these adolescents may not have
Abstract reasoning to think through their behaviors and resulting consequences, they do have concrete thinking abilities and can learn right from wrong. Because of this, supervision is needed to anticipate problems and help the adolescent make healthy decisions.
Youths with mild MR are at the highest risk of engaging in high risk behavior, becoming victims of physical, sexual and mental abuse. Because they generally have greater autonomy and live independently as they become adults, they have more opportunities to get into trouble. They often are the patsies and prey of smarter individuals who can easily talk them into engaging in high risk behaviors. Some of them often do not have the ability to think before they act without prompting and get caught when committing a crime or anti-social act. They are unable to think fast enough to tell a convincing lie to escape trouble. Because they lack the ability to anticipate what might happen next, and are generally very susceptible to the emotional context of a situation, they react to that emotion and escalate problem.
Caregivers must work very hard to enroll these youth in programs that teach prosocial behavior and problem- solving skills. They need to be surrounded by advocates who help them and come to their aid when they get into trouble. Physicians need to encourage parents and caregivers to constantly and repeatedly teach survival skills to these youth.
Special Consideration for Adolescent Depression and Suicide
Depressive disorders, which include major depressive disorder (unipolar depression), dysthymic disorder (chronic, mild depression), and bipolar disorder (manic-depression), can have far-reaching effects on the functioning and adjustment of young people. Among adolescents, depressive disorders confer an increased risk for illness and interpersonal and psychosocial difficulties that persist long after the depressive episode is resolved; in adolescents there is also an increased risk for substance abuse and suicidal behavior
Adolescents with depression may have difficulty in properly identifying and describing their internal emotional or mood states. For example, instead of communicating how bad they feel, they may act out and be irritable toward others which may be interpreted simply as misbehavior or disobedience. Research has found that parents are even less likely to identify major depression in their adolescents than are the adolescents themselves. These factors are especially true for adolescents with limited cognitive functioning.
Suicidal risk is also very high among these youths because of their limited cognitive functioning, especially the absence of
Abstract and futuristic thinking. When an adolescent with mild to moderate MR expresses suicidal tendency the physician and all care givers must directly and clearly tell the youth that that is unacceptable and inappropriate behavior. They must then help the adolescent clearly identify reasons to live and develop a concise and simple plan to live. This should include who the adolescent is to contact when he or she feels like wanting to hurt him or herself. It is essential that physicians do not ignore the risks of not detecting and treating depression in this group of youth. Because these youth generally have slowed thinking and response times to stimuli in the environment, the physician must take this into account with prescribing medications.
Risk of Academic Failure
Adolescents with mild to moderate MR are at risk of experiencing academic problems and even failure. These youths often do not qualify for Special Education services because their academic functioning often commensurates with their intellectual functioning. Extra or supportive services are frequently not available to these youth. Adolescents who struggle in school are at risk of dropping out of school and all the other associated problems. Physicians should encourage parents to enter their adolescents in skill training programs, and/or to provide extra tutoring and encouragement to learn.
CONCLUSION
0Adolescents with MR are at risk of a wide range of psychosocial problems. It is important that physician recognize that depending on the particular syndrome, these youths will experience various forms and levels of problems and require various levels of intervention to survive and succeed. Youth with mild forms of MR can learn to be independent with support and encouragement.
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