Fragile X syndrome is a common hereditary cause of mental retardation and learning disability. Both males and females can be affected by Fragile X syndrome, although females often have milder effects. Males with Fragile X syndrome usually have mental retardation, and may have some autistic-like behaviors. Females with Fragile X syndrome may have mental retardation or learning disabilities, social difficulties, and anxiety.
(Source: Department of Brain Imaging, Stanford University)
Turner syndrome is a genetic disorder that occurs only in females and arises from partial or complete absence of the X chromosome. Turner syndrome occurs in about 1 in 2500 female births. Physical manifestations of this syndrome include some of the following: gonadal dysgenesis, lack of pubertal maturation, infertility, short stature, shield chest, webbing of the neck, coarctation of the aorta, and horseshoe kidney. The neurocognitive profile of females with Turner syndrome includes: preserved verbal skills as well as specific deficits in visuo-spatial tasks, visual memory, and arithmetic.
(Source: Department of Brain Imaging, Stanford University)
William's syndrome is a rare genetic disorder occurring 1 in approximately 25,000 live births. Dr. J.C.P. William's first defined the syndrome when he noticed that many children entering his hospital with cardiovascular problems shared other traits in common, particularly facial features and an unusually friendly and social demeanor.
Physical traits can include: hypercalcemia (high blood calcium levels, possibly producing colic-like symptoms), failure to thrive (slow or stunted growth), delayed development, widely spaced teeth, and long philtrum. Neurologic and behavioral symptoms can include: impaired visuospatial abilities with preserved facial processing, impaired problem solving, preserved language abilities, love of music, anxiety, attention deficit, hyperacusis (hypersensitivity to loud noises), friendly and outgoing demeanor.
(Source: Department of Brain Imaging, Stanford University)
Velo-Cardio-Facial syndrome (VCFS) is a genetic, autosomal dominant condition with a frequency estimated at 1 per 4000 live births. In most cases, the condition is not inherited from parent to child. The features of VCFS include cardiac malformations, cleft palate or velopharyngal insufficiency, a characteristic facial appearance, learning disabilities and more than 40 other physical anomalies.
Studies indicate that nearly half of individuals with VCFS have mental retardation. Particular problems with abstract reasoning, language delay, mood regulation, monotonous voice, and difficulties in social interaction have been described (Golding-Kushner et al., 1985). A nasal speech tone is observed in the vast majority of individuals with VCFS as well as difficulties with articulation whose origin is assumed to be the cleft palate and pharyngeal hypotonia.
(Source: Department of Brain Imaging, Stanford University)
Autism and the other pervasive developmental disorders (PDDs) are complex neurodevelopmental disorders that typically appear during the first three years of life. Children and adults affected by autism/PDD have difficulties in social interactions, in acquisition and use of language, and in leisure and play activities. The disorders may also be characterized by repetitive movements, self-injurious behavior, resistance to changes in routines, and increased sensitivity to sensations such as touch or sound. Autism/PDD are believed to be caused by neurological differences that have yet to be fully explained. Autism and related pervasive developmental disorders (e.g., Asperger's disorder and PDD not otherwise specified) occur in approximately 15 in 10,000 live births, and affect all races, ethnicities, and social groups.
(Source: Department of Brain Imaging, Stanford University)
Attention-Deficit Hyperactivity Disorder (ADHD) is a disorder that occurs in 3-5% of school age children. Children with ADHD show inattention, distractibility, impulsivity, or hyperactivity more frequently and severely than other children of the same age or developmental level. For a child to be diagnosed with ADHD, these characteristics must begin before the age of seven and can continue into adulthood. ADHD runs in families with about 25% of biological parents also having this medical condition.
A child with ADHD often displays some of the following characteristics: trouble paying attention, inattention to details, making careless mistakes, being easily distracted, losing school supplies, forgetting to turn in homework, trouble finishing class work and homework, trouble listening, impatience, trouble following multiple adult commands, blurting out answers, fidgeting or squirming, leaving seat and running about or climbing excessively, being "on the go", talking too much and having difficulty playing quietly, and interrupting or intruding on others.
(Source: American Academy of Child & Adolescent Psychiatry)