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近年来,智力低下的研究有一项重大的发现—脆性X综合征（简称脆X征）。脆X征是指一类智力低下男性,他们的X染色体末端（Xq27.3）有一个标记。脆X征基本上按X连锁方式遗传。已知有50种X连锁遗传病和智力障碍有联系,除脆X征外,其他疾病都是十分罕见的。初步估计脆X征的患病率仅次于先天愚型。由于先天愚型起因于散发的染色体不分离,而脆X征的孟德尔方式遗传,因而脆X征是最常见的遗传性智力低下。脆X征的遗传规律、诊断和产前诊断的研究,对于减少智力低下儿的出生,提高人口素质有重要意义。
In recent years, the study of mental retardation has a major discovery - Fragile X syndrome (referred to as fragile X sign). Fragile X sign refers to a group of men with mental retardation who have a marker at the X chromosome end (Xq27.3). Crisp X sign basically by X-linked genetic. Known 50 kinds of X-linked genetic disease and mental retardation are linked, in addition to crisp X signs, other diseases are very rare. Preliminarily estimate the prevalence of crisp X-ray signs second only to Down’s syndrome. Because of Down’s syndrome is due to disseminated chromosomes are not separated, and Mendelle crisp X-levy way genetic, so crisp X-sign is the most common genetic mental retardation. The study of the genetic laws, diagnosis and prenatal diagnosis of crisp X sign is of great significance to reduce the birth of children with mental retardation and improve the quality of the population.