精神发育迟滞(旧称智力低下)作为儿科神经科常见的一组疾患,具有高度的遗传和表型异质性,大约25%~50%的精神发育迟滞是由遗传因素引起的,其中X染色体基因/基因组变异占25%~30%,导致X连锁的精神发育迟滞。X连锁的精神发育迟滞患者占所有精神发育迟滞患者的10%~15％以上,约20%~25％的男性精神发育迟滞归因于X连锁的精神发育迟滞。精神发育迟滞男女患病比例为1.3:1,这与男性只有一条X染色体的遗传背景有关。随着新一代基因组检测技术的快速发展和临床应用,尤其是全外显子测序、高深度测序、X染色体深度测序和全基因组芯片杂交,这些大大改善了精神发育迟滞患者的X染色体基因/基因组变异检出。本文综述了致精神发育迟滞的X染色体基因组/基因变异特点、其对男性精神发育迟滞的致病性,以及如何采用新测序技术提高检出率,旨在促进科研人员认识X染色体变异在男性精神发育迟滞的致病性,拓宽精神发育迟滞遗传病因的认识,同时也为遗传咨询和产前诊断提供理论依据。

Intellectual Disability (ID, previously named mental retardation) is a group of common pediatric neurology disorders characterized by extensive genetic and phenotypic heterogeneity. About 25%-50% of ID was caused by genomic/genetic variants, in which genomic/genetic variants of X-chromosome are one of key pathogenic causation (25%-30%), resulting in X-linked ID (XLID). The epidemiological data showed that the male to female ratio is 1.3: 1 in ID patients. The prevalence of XLID in the whole ID population is 10%-15%, and this prevalence reaches 20%-25% in the male ID population. This sex-related differential proportion of ID may be attributed to hemizygosity of X chromosomes in males. A quick detection of genomic/genetic aberrations of X chromosome is feasible and available now due to the overwhelming development of next-generation genomic techniques and their clinical applications; in particular, whole exome sequencing, customer-designed whole genomic chip for the X chromosome, high-density target sequencing and whole X chromosomal sequencing are used widely for clinical diagnosis. In this review, we systematically summarize the pathogenicity and characteristics of X-chromosomal genomic/genetic aberrations in the male patients with ID, and how the new technologies have been used to detect X-chromosomal abnormalities. This review will help researchers understand the pathogenicity of X-chromosomal variations in male ID patients from the view of whole genome, refresh the knowledge about the genomic/genetic etiology of ID, and further provide a theoretical basis for genetic counseling and prenatal diagnosis in the future.