Fragile Sites are regions of genomes that are prone to breakage. In human cells, rare fragile sites are due to expansion of repetitive sequences which have been either shown or predicted to form DNA secondary structures such as hairpins, cruciforms, and quadruplexes. For human common fragile sites, which are components of normal chromatin structure, are induced by replication inhibitors, and en...

The fragile X mental retardation 1 gene (FMR1), which codes for the fragile X mental retardation 1 protein (FMRP), is located at Xp27.3. The normal allele of the FMR1 gene typically has 5 to 40 CGG repeats in the 5' untranslated region; abnormal alleles of dynamic mutations include the full mutation (> 200 CGG repeats), premutation (55-200 CGG repeats) and the gray zone mutation (45-54 CGG repe...

Physiological arousal was measured in 12- to 22-year-old females with either fragile X, Turner syndrome, or neither disorder to explore potential differences in the manifestation of arousal and anxiety in adolescents and young women. Physiological arousal was measured at baseline and during performance on mental arithmetic, divided attention, and risk-taking tasks. Contrary to prediction, femal...

OBJECTIVE Fragile X syndrome, caused by mutations in a single gene of the X chromosome (FMR1), is associated with neurobehavioral characteristics including social deficits with peers, social withdrawal, gaze aversion, inattention, hyperactivity, anxiety, depression, and autistic behavior. However, there is considerable variability in the behavioral and psychiatric problems among children with t...

The fragile X mutation and fragile X syndrome are associated with hyperarousal, hyperactivity, aggression, and anxiety. These may be related to strong reactions to auditory, tactile, visual, and olfactory stimuli [Hagerman, 1996b; Hagerman and Cronister, 1996]. However, almost no data exist describing hyperarousal and sensory sensitivity in individuals with the fragile X mutation. This study es...

In various studies of sporadic breast cancers, 40-70% were strongly positive for fragile histidine triad (Fhit) protein expression, whereas only 18% of BRCA2 mutant breast cancers demonstrated strong Fhit expression, suggesting that the BRCA2 repair function may be necessary to retain intact fragile common chromosome fragile site 3B(FRA3B)/FHITloci. In the current study, 22 breast tumors with d...

Fragile site breakage was previously shown to result in rearrangement of the RET oncogene, resembling the rearrangements found in thyroid cancer. Common fragile sites are specific regions of the genome with a high susceptibility to DNA breakage under conditions that partially inhibit DNA replication, and often coincide with genes deleted, amplified, or rearranged in cancer. While a substantial ...

Fragile X syndrome, the most common form of hereditary mental retardation, causes disruption in the development of dendrites and synapses, the targets for axonal growth in the central nervous system. This disruption could potentially affect the development, wiring, and targeting of axons. The current study utilized diffusion tensor imaging (DTI) to investigate whether white matter tract integri...

The fragile X syndrome is the most frequent cause of inherited mental retardation. It is caused by a dynamic mutation: the progressive expansion of polymorphic (CGG)n trinucleotide repeats located in the promoter region of the FMRI gene at Xq27.3. The cloning of the FMRI gene and the elucidation of the molecular basis of the fragile X syndrome is of great importance for the diagnosis and unders...