Molecular-intelligence correlations in young fragile X males with a mild CGG repeat expansion in the FMR1 gene
- Central of Clinical Genetics, Maastricht (Netherlands)
- University Hospital Gasthuisberg, Leuven (Belgium); and others
Several mechanisms can explain the occurrence of full-mutation fragile X males with an IQ level above -2 SD below mean, also called {open_quotes}high-functioning fragile X males.{close_quotes} Incomplete methylation of the CpG island at the 5{prime} end of the FMR1 gene is one of these mechanisms. The present study describes the physical and behavior phenotypes in 7 fragile X boys with CGG repeat insertions in the FMR1 gene between 600-2,400 base pairs. The degree of methylation at the FMR1-associated CpG island ranges in peripheral blood lymphocytes from 0-95%. Subjects with a low degree of methylation at this site have mild or absent physical characteristics of the fragile X syndrome, while subjects with a high degree of methylation at this site have more severe physical characteristics. In this range of CGG repeat insertion (600-2,400 base pairs), the degree of methylation at the FMR1-associated CpG island is a good predictor of intelligence, while CGG repeat insertion length is not. 13 refs., 1 fig., 1 tab.
- OSTI ID:
- 478880
- Journal Information:
- American Journal of Medical Genetics, Journal Name: American Journal of Medical Genetics Journal Issue: 2 Vol. 64; ISSN 0148-7299; ISSN AJMGDA
- Country of Publication:
- United States
- Language:
- English
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