Tzancheva M, Kaneva R, Kumanov P, Williams G, Tyler-Smith C
Department of Medical Genetics, State University Hospital Queen Giovanna, Sofia, Bulgaria.
J Med Genet. 1999 Jul;36(7):549-53.
Turner syndrome is thought to result from the haploinsufficiency of genes on the sex chromosomes, but these genes have not been identified yet. We describe two males with deleted ring Y chromosomes, one (TS) with full Turner syndrome and one (DM) without. TS has short stature, skeletal anomalies, lymphogenic obstruction, cardiovascular abnormalities, and miscellaneous features including pigmented naevi, antimongoloid slanting of the palpebral fissures, and widely spaced nipples. In contrast, DM has short stature but no other specific Turner stigmata except high arched palate and a few pigmented naevi. Since little chromosomal mosaicism was detected, the different segments of the Y chromosome retained by these two males identify the location of one or more "anti-Turner" genes. Most of the Yp pseudoautosomal region and Yq were deleted from both patients during the formation of the ring chromosome, while the Y specific portion of Yp and the centromere were retained. The major difference detected was an interval of proximal Yq present in DM and deleted in TS. None of the previously identified genes, DFFRY, DBY, UTY, or TB4Y, lies entirely within this interval, although DFFRY was truncated by DM's breakpoint. These data suggest that one or more additional "anti-Turner" gene(s) remains to be identified in the region of Yq proximal to DFFRY.
特纳综合征被认为是由于性染色体上基因的单倍剂量不足所致,但这些基因尚未被确定。我们描述了两名患有Y染色体环状缺失的男性,其中一名(TS)患有完全型特纳综合征,另一名(DM)则没有。TS身材矮小、骨骼异常、淋巴生成受阻、心血管异常,还有包括色素痣、睑裂反蒙古样倾斜和乳头间距增宽等多种特征。相比之下,DM身材矮小,但除了高拱腭和一些色素痣外,没有其他典型的特纳综合征体征。由于检测到的染色体嵌合体很少,这两名男性所保留的Y染色体不同片段确定了一个或多个“抗特纳”基因的位置。在环状染色体形成过程中,两名患者的Y染色体大部分假常染色体区域和长臂均缺失,而Y染色体短臂的Y特异性部分和着丝粒得以保留。检测到的主要差异是DM中存在而TS中缺失的Yq近端区间。尽管DM的断点截断了DFFRY,但之前鉴定的基因DFFRY、DBY、UTY或TB4Y均不完全位于此区间内。这些数据表明,在DFFRY近端的Yq区域仍有待鉴定一个或多个额外的“抗特纳”基因。