The fragile X syndrome.

Journal article

An amplification of a highly unstable DNA element has been identified at the fragile X locus in Xq27.3. This sequence appears to be both the source of the primary mutation causing the fragile X syndrome, apparently having its causative effect through the methylation of the FMR-1 HTF island and the region of cytogenetic fragility. The direct analysis of the genotype of carrier and affected individuals can be used as a direct diagnosis tool which will improve both the accuracy and speed of diagnosis. The identification of hereditary unstable DNA in a disease with such a wide level of non-penetrance and variable phenotype may give clues as to the basis of non-penetrance in other human genetic disorders.

Authors: Hirst, M; Knight, S; Bell, M; Super, M; Davies, K

• Journal: Clinical science (London, England : 1979)
• Volume: 83
• Issue: 3
• Pages: 255-264
• Publication date: 1992-09-01
• EISSN: 1470-8736
• ISSN: 0143-5221
• Language: English
• Keywords: Heterozygote Detection; Genetic Linkage; Female; Fragile X Syndrome; Humans; Gene Amplification; DNA; Genetic Markers; Male; Mutation; Chromosome Fragility