Background: Fragile X Syndrome (FXS) is the second cause of Mental Retardation (MR) and the first cause of familiar MR. This syndrome affects up to 1/4000 men and 1/8000 women. X syndrome is often diagnosed by molecular biology technique such as RCR and Southern blot. Until now there is no study on FXS in Vietnam. Objectives: This study is aimed at: (1) Determine FXS among children with MR by technique of molecular biology. (2) Determine the mutation of FMR1 gen in families having children with FXS. Subject and Method: 214 children between 6 and 16 years of age (136 male and 78 female) with MR were analyzed FMR1 gen by PCR and Southern blot techniques. Families of children with FXS were also analyzed. Result and conclusion: This is the first study on FXS using the techniques of molecular biology in Vietnam. Identified 3 children with FXS, accounting for 1.4% of MR. Children with FXS and members with full mutation and premutation were found.
Fragile X syndrome ; FMR1 gene ; Mental retardation