Syndrome

Fragile X syndrome is the most important X-linked etiology of memal retardation and developmental disability curren@ known.Accumulating evidence also indicates that male and female carriers of the fragile X genetic abnormality demonstrate a relatively specific pattern of psychiatric disturbance.Fragile X males frequently manifest behaviors from t.he autistic spectrum whereas fet,~les show dysfunction in social interaction, thought processes, and affective regulation, in this review, an overview of the fragile X syndrome is presented with a focus on the occurrence of particular neuropsychiatric characteristics in males and females.Relevant data from recent genetic and neurobiological research is also described.The ability to study individuals with a specific genetic cause of psychopathology such as fragile X syndrorae makes this condition of particular interest to biological psychiatry. Introdt,ctionFragile X syndrome is the most important X-linked condition associated with mental retardation and developmental disability currently known.It was originally described as an X-linked mental retardation (XLMR) syndrome, it is now recognized that there is a broad spectrum of behavioral and cognitive disabilities associated with this genetic condition, both in male hemizygotes and female heterozygotes.Fragile X is the most common known heritable cause and, at least, the second mo~t common specific genetic form of mental retardation in males and females (Opitz 1986).From rite perspective of biological psychiatry., interest in fragile X syndrome stems from the accumulating evidence indicating that individuals with tihe fragile X genetic abnormality demonstrate a relatively specific pattern of behavioral and developmental problems.Affected fragile X males typically have significant developmental delays and mental retardation.One of the most important aspects of the observed neurobehavioral phenotype in males is the presence of autistic behavior (Brown et al. 1986;Hagerman et al. 1986; Cohen et al. 1988).Fragile X males are a!so reported to show an increased frequency and severity of hyperactivity: self-injury, perseveration, stereotypic motor