Arinami T, Kondo I, Nakajima S, Hamaguchi H
Hum Genet. 1987 Aug;76(4):344-7. doi: 10.1007/BF00272442.
The fragile X [fra(X)] syndrome was screened on 190 Japanese institutionalized females with moderate to severe mental retardation. Two inmates with severe mental retardation (IQ 20) had the fra(X) chromosome in 26% and 15% of the cells examined, indicating that the prevalence of the fra(X) syndrome was about 1% in all female inmates and was about 3.27% in severely mentally retarded females without known causes. However, no female with fra(X) syndrome was found in 35 moderately retarded females. Both had brothers with the fra(X) syndrome and the prevalence was 10% in females with a family history of mental retardation. In addition, the replication study of the fra(X) chromosome in the patients supported the proposal that an excess of the early replicated fra(X) chromosome is related to the mental capacity in heterozygous females. Therefore, the fra(X) syndrome should not be ignored even in severely mentally retarded females with a family history, though the heterozygotes are commonly normal to subnormal in their mental development. In addition, the replication study of the fra(X) chromosome may help to estimate mental development in the carrier children.
对190名中度至重度智力障碍的日本机构收容女性进行了脆性X [fra(X)]综合征筛查。两名重度智力障碍（智商20）的被收容者，在所检查的细胞中，分别有26%和15%的细胞存在fra(X)染色体，这表明在所有女性被收容者中，fra(X)综合征的患病率约为1%，在病因不明的重度智力障碍女性中约为3.27%。然而，在35名中度智力障碍女性中未发现fra(X)综合征患者。她们都有患fra(X)综合征的兄弟，在有智力障碍家族史的女性中，患病率为10%。此外，对患者fra(X)染色体的复制研究支持了这样的观点，即早期复制的fra(X)染色体过多与杂合子女性的智力水平有关。因此，即使在有家族史的重度智力障碍女性中，fra(X)综合征也不应被忽视，尽管杂合子在智力发育上通常正常至轻度低于正常水平。此外，对fra(X)染色体的复制研究可能有助于评估携带者儿童的智力发育。
