Name
FRAGILE X SYNDROME
DESCRIPTION
DETAIL
CAUSES Transmission of affected X chromosome -------------------------------------------------------------------------- DIFFERENTIAL DIAGNOSIS β’ Fragile X syndrome should be considered in patients (male or female) with mental retardation of unknown etiology β’ Many male children will present primarily with speech delay or overgrowth and may have been misdiagnosed as having cerebral gigantism (Soto) syndrome β’ Males or females with significant learning disabilities with speech and language deficits β’ Familial pattern of MR β’ Pervasive developmental disorder β’ Significant learning disability β’ FRAXE - cytogenetically positive/DNA negative β’ Autism β’ William syndrome* Molecular genetic testing (DNA) is the diagnostic test of choice. Molecular studies can identify full mutations, mosaic patterns, and permutations thereby identifying affected carriers among normal relatives. SPECIAL TESTS : Affected patients are in need of educational and psychological evaluation for the development of learning programs
TYPENOTES
RISK FACTORS: Transmitting males are intellectually normal and pass the affected chromosome to all of their daughters, the latter who may have affected sons β’ Affected females transmit the affected chromosome totheir offspring on a 50/50 chancAPPROPRIATE HEALTH CARE : β’ Affected individuals will usually require life-long adult supervision and should be referred to the local mental retardation board for case management β’ Clinical trials assessing the effects of ampakine CX516 (Ampalex) on cognition and functioning are underway GENERAL MEASURES : Early detection allows initiation of pre-school intervention programs DRUG(S) OF CHOICE Folic acid 20 mg qd, has been reported anecdotally to improve behavior and attention span in prepubertal males. No statistically signifi cantly benefi t has been observed in children or adults during double-blind studies. PATIENT MONITORING General health maintenance PREVENTION/AVOIDANCE Genetic counseling and evaluation of at-risk family members and pregnancies. Prenatal diagnosis is available. POSSIBLE COMPLICATIONS Severe learning and/or behavioral problems; the latter of which are more frequent among female patients EXPECTED COURSE/PROGNOSIS : β’ Males with a full mutation may require life-long adult supervision β’ Among affected males and females, life-span is generally not affected β’ Among males, intellect manifests early plateauing which causes a decline in IQ scores β’ Females are less affected but may have mild to moderate mental retardation β’ Approximately 1/3 of affected females manifest learning disabilities
RELATED DISEASE
Not Available Disease
DISEASE
INVESTIGATION
COMPLETE BLOOD COUNT, KARYOTYPING