Cognitive Features. Males. Females. Inheritance Pattern

A. Males. Intellectual abilities in fragile X males can range from severe learning disabilities in the normal IQ range to profound retardation. The majority of adult fragile X males are moderately retarded. Fragile X boys often present in the preschool years with IQ abilities in the low normal to borderline range. These higher cognitive abilities are usually a reflection of their areas of cognitive strength, which include single word expressive vocabulary abilities, isolated visual perceptual abilities such as visual matching tasks, and imitation.

Almost all fragile X males, however, demonstrate significant weaknesses in higher linguistic abilities such as abstract reasoning skills, ability to generalize and solve novel problems, and memory deficits. These abilities, particularly the reasoning abilities, become more important in middle and later childhood and are reflected in the score on IQ testing. Many fragile X children will demonstrate a decrease in their IQ score through middle and later childhood and adolescence. Fragile X children do not lose cognitive abilities and, in fact, they continue to learn and increase their ability through time.

However, the emphasis of cognitive testing in later childhood and adolescence stresses their weak areas, such as abstract reasoning. Math is a consistent weakness for almost all fragile X males and it usually is their most profound deficit in the academic area. Many higher-functioning fragile X males will learn to read and they may even maintain reading and spelling abilities at their grade level.

B. Females. Approximately 50% of females with the full mutation have cognitive deficits, including a borderline IQ or mental retardation. Of females with the full mutation and a normal IQ, disabilities are common. Females who are cognitively impaired with learning disabilities or mental retardation usually demonstrate their greatest deficit in mathematics. Cognitive testing using the Wechsler Intelligence Scale has demonstrated a profile of strengths and weaknesses in the subtest scores. A pattern of weakness can be seen in the subtests of Arithmetic, Digit Span, and Block Design. Areas of strength include the Vocabulary and Digit Symbol subtests. These profiles are seen in the analysis of group data but may be inconsistently present when looking at a particular individual.

Inheritance Pattern. The discovery of a new form of mutation in fragile X syndrome, specifically a trinucleotide repetitive sequence that grows from generation to generation, has led to similar discoveries in other disorders that become worse (start earlier or have a more severe form) from generation to generation. This phenomenon is called anticipation. Myotonic dystrophy, Huntington’s chorea, and spinocerebellar atrophy all demonstrate anticipation and all have been found to have a similar mutation pattern as seen in fragile X, that is, a trinucleotide repeat sequence that increases in size from generation to generation.

Special Education. All children who are affected by the fragile X syndrome will require special education help. For higher functioning individuals, this may involve only pullout remediation from a regular classroom setting. Many children with fragile X syndrome can be included into the regular classroom with the help of an aide who can modify assignments. For more significantly retarded individuals, a self-contained placement may be necessary, particularly when severe hyperactivity and a short attention span are complicating features. Fragile X children often respond well to mainstreaming because they usually mimic the behavior of children who surround them. If the classmates have normal behavior, then the fragile X child is more likely to develop normal behavior patterns. If fragile X children are placed in a group of children with significantly deviant behavior, then fragile X children often mimic more deviant behavioral characteristics.

Special education help is also essential for learning disabled individuals, particularly females and higher functioning males. Math deficits are the most common academic problem and individualized help is usually necessary. Many learning disabled individuals demonstrate high achievement in reading and spelling, although deficits can also be seen that require remediation. Attentional problems may be present in normal IQ individuals and stimulant medication, in conjunction with special education, is useful.

Counseling or psychotherapy can be helpful on an individual basis and in family work. Behavior modification techniques can be taught to parents to guide them in improving their child’s behavior. Individual work can be useful, particularly for the adolescent or adult male with fragile X syndrome, to help him deal with sexuality issues and aggression.