Fragile X syndrome (an FMR1–related disorder) is the most commonly inherited form of mental retardation. Early physical recognition is difficult, so boys with developmental delay should be strongly considered for molecular testing. The characteristic adult phenotype usually does not develop until the second decade of life. Girls can also be affected with developmental delay. Because multiple fa...

We have begun to appreciate that the extent of this disorder is much wider than merely mental retardation. It is also a common cause of learning and emotional problems in mildly affected female carriers with normal IQs. These children present an enormous challenge to all child-care providers, be they in medicine, education, or in various therapy disciplines. Early identification is essential, a...

Fragile X Syndrome, the most common form of inherited mental retardation, is characterized by autistic behavior and mild to severe learning disabilities. The disease is caused by the expansion of a trinucleotide repeat located on the FMR1 (Fragile X Mental Retardation) gene located on the Xchromosome. Since the early 1990s, 348 prenatal female samples have been analyzed for Fragile X Syndrome a...

Many of the diverse functional consequences of activating group 1 metabotropic glutamate receptors require translation of pre-existing mRNA near synapses. One of these consequences is long-term depression (LTD) of transmission at hippocampal synapses. Loss of fragile X mental retardation protein (FMRP), the defect responsible for fragile X syndrome in humans, increases LTD in mouse hippocampus....

OBJECTIVE To examine longitudinally the adaptive behavior patterns in fragile X syndrome. METHOD Caregivers of 275 children and adolescents with fragile X syndrome and 225 typically developing children and adolescents (2-18 years) were interviewed with the Vineland Adaptive Behavior Scales every 2 to 4 years as part of a prospective longitudinal study. RESULTS Standard scores of adaptive be...

The influence of social and information-processing demands on eye-gaze avoidance in individuals with fragile X syndrome, Down syndrome, or typical development were examined by manipulating those demands in a structured-language task. Participants with fragile X syndrome exhibited more gaze avoidance than did those in the comparison groups, but no group differences in avoidance were found betwee...

Fragile X syndrome occurs as a result of a mutation of the fragile X mental retardation 1 (FMR1) gene on the bottom of the X chromosome (Pic. 1), which encodes fragile X mental retardation protein (FMRP). This protein, most commonly found in the brain, is essential for normal cognitive development and female reproductive function. The CGG triplet that means gene segment consisting of a cytosine...

Fragile X syndrome occurs as a result of a mutation of the fragile X mental retardation 1 (FMR1) gene on the bottom of the X chromosome (Pic. 1), which encodes fragile X mental retardation protein (FMRP). This protein, most commonly found in the brain, is essential for normal cognitive development and female reproductive function. The CGG triplet that means gene segment consisting of a cytosine...

groups with asthma. Thus the scientist must weigh the advantages of performing genetic studies in small, historically isolated populations with the potential disadvantage of being unable to eventually generalize the studies’ results. SEE ALSO Genetic Drift; Hardy-Weinberg Equilibrium; Inbreeding; Linkage and Recombination; Mapping; Population Bottleneck; Population Genetics; Tay-Sachs Disease.