[Genetics of Fragile X syndrome and its prevention].
The fragile X syndrome is the most common inherited form of mental retardation. Its prevalence is estimated to be one in 1000-4000 males and one in 2000-6000 females, depending of the region. A large canadian population study in Quebec has shown a frequency of 1/260 carrier women. The fragile X syndrome was the first disease shown to be associated with "dynamic mutations", caused by an amplification of an unstable DNA sequence transmitted from generations to generations till a pathologic expression: mental retardation. The prevention is possible by a specific DNA analysis of patients and male and female carriers. It is possible to detect the mutation or the premutation in pregnant women and to propose a prenatal diagnosis by molecular study on chorionic villi samples or cultivated amniocytes.
Boué
J
J
Hôpital Cochin, Port Royal, Paris.
Simon-Bouy
B
B
D005260:Female; D005600:Fragile X Syndrome / Q000453:epidemiology / Q000235:genetics* / Q000517:prevention & control*; D005787:Gene Frequency; D006580:Genetic Carrier Screening; D005820:Genetic Testing; D006801:Humans; D008297:Male; D009154:Mutation; D010375:Pedigree; D011247:Pregnancy; D011296:Prenatal Diagnosis; D015995:Prevalence