Diagnostic testing in fragile X syndrome
Sireteanu, A.; Rusu, C.
Revista Medico-Chirurgicala a Societatii de Medici Si Naturalisti Din Iasi 110(4): 968-971
2006
ISSN/ISBN: 0048-7848 PMID: 17438909 Document Number: 604905
Fragile X syndrome is the most common inherited cause of mental retardation. It is caused by a progressive expansion of polymeric (CGG)n trinucleotide repeats located on the FMR1 gene at Xq27.3. The spectrum of clinical involvement is broad, clinical diagnosis being difficult especially in young children. Hence, all cases of mental retardation without obvious cause should be tested for fragile X syndrome; the relatives of such a case need to be offered genetic counseling. Cytogenetic and molecular diagnostic tests are available. Recently, an immunocytochemical test has been described to identify fragile X patients, based on detection of FMR1 protein in cells using a monoclonal antibody. This method is used for screening, PCR based tests and Southern blot hybridization being the diagnostic tests for mutation and pre-mutation detection. Prenatal diagnosis is possible.