Blomquist H K, Gustavson K H, Holmgren G, Nordenson I, Pålsson-Stråe U
Clin Genet. 1983 Dec;24(6):393-8. doi: 10.1111/j.1399-0004.1983.tb00092.x.
In an extensive etiological study of an unselected series of mildly mentally retarded children (MMR) (IQ 50-70) born 1959-1970 in a northern Swedish county, 5 of 110 boys (4.5%) and none of 61 girls had a fragile site on the distal end of the X-chromosome (Fra Xq 28). Consequently fragile X was seen in 2.9% of the total series of 171 children. In a combined series of severe and mild mental retardation, the incidence of the fragile X syndrome was calculated to be 1:3000 in the county of Västerbotten. Next to trisomy 21 the fragile X syndrome was the most common single identified cause of MMR in boys. A cytogenetic investigation using special cultural conditions and banding techniques should be performed in cases of mental retardation of unclear etiology and in possible female carriers.
在一项针对瑞典北部某郡1959年至1970年间出生的未经筛选的轻度智力发育迟缓儿童（MMR）（智商50 - 70）系列的广泛病因学研究中，110名男孩中有5名（4.5%）在X染色体远端有脆性位点（Fra Xq 28），而61名女孩中无一例有该位点。因此，在171名儿童的总样本中，脆性X的出现率为2.9%。在重度和轻度智力发育迟缓的综合样本中，韦斯特博滕郡脆性X综合征的发病率经计算为1:3000。除21三体综合征外，脆性X综合征是男孩中MMR最常见的单一明确病因。对于病因不明的智力发育迟缓病例以及可能的女性携带者，应采用特殊培养条件和显带技术进行细胞遗传学检查。
