The high prevalence of fragile X premutation carrier females: Is this frequency unique to the French Canadian population?
- Emory Univ., Atlanta, GA (United States)
{open_quotes}The fragile X syndrome is the most common inherited form of mental retardation and, after Down syndrome, the most common identified form of mental retardation.{close_quotes} Although statements similar to this are found in almost every introduction to the fragile X syndrome, little is actually known about the true prevalence of fragile X syndrome or about the frequency of clinically unaffected carriers. To date, almost all estimates of the prevalence of the syndrome are based on cytogenetic surveys of overtly retarded populations. The cytogenetic test to detect the fragile X site expression is labor intensive, and its sensitivity and specificity are considerably less than 100%. Thus, once the gene for the fragile X syndrome was isolated, population surveys of the mutation were anticipated, as the DNA diagnostic test is accurate, relatively simple, and inexpensive compared with the cytogenetic test. However, population surveys have been slow to come, in part, because of the technical difficulties related to the type of sample tested (e.g., blood spot) and to ethical and logistical problems related to identification of a target population. Dr. Rousseau and his colleagues have overcome these difficulties and present in this issue of the journal the first large study of the frequency of clinically unaffected female carriers of the fragile X mutation. 21 refs.
- OSTI ID:
- 209887
- Journal Information:
- American Journal of Human Genetics, Vol. 57, Issue 5; Other Information: PBD: Nov 1995
- Country of Publication:
- United States
- Language:
- English
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