X-linked dominant disorders that are exclusively lethal prenatally in hemizygous males have been described in human and mouse1. None of the genes responsible has been isolated in either species. The bare patches (Bpa ) and striated (Str) mouse mutations were originally identified in female offspring of X-irradiated males2,3. Subsequently, additional independent alleles were described. We have previously mapped these X-linked dominant, male-lethal mutations to an overlapping region of 600 kb that is homologous to human Xq28 (ref. 4) and identified several candidate genes in this interval5. Here we report mutations in one of these genes, Nsdhl, encoding an NAD(P)H steroid dehydrogenase-like protein, in two independent Bpa and three independent Str alleles. Quantitative analysis of sterols from tissues of affected Bpa mice support a role for Nsdhl in cholesterol biosynthesis. Our results demonstrate that Bpa and Str are allelic mutations and identify the first mammalian locus associated with an X-linked dominant, male-lethal phenotype. They also expand the spectrum of phenotypes associated with abnormalities of cholesterol metabolism.
人类和小鼠中都有X连锁显性遗传病,这种病在单倍体雄性中仅在产前致死,1。但在这两种物种中,都没有分离出相关的
基因。裸斑(Bpa)和条纹(Str)小鼠突变最初是在X射线照射雄性小鼠的雌性后代中发现的2,3。随后,又发现了其他独立等位
基因。我们之前将这些X连锁显性、雄性致死突变定位到与人类Xq28同源的600kb重叠区域(参考文献4),并在此区间内确定了几个候选
基因5。在此,我们报告了其中一种
基因Nsdhl的突变,该
基因编码一种
NAD(P)H类
固醇脱氢酶样蛋白,在两个独立的Bpa和三个独立的Str等位
基因中都有突变。对患病Bpa小鼠组织中的
固醇进行定量分析,证实了Nsdhl在
胆固醇生物合成中的作用。我们的研究结果表明,Bpa和Str是等位
基因突变,并确定了第一个与X连锁显性、雄性致死表型相关的哺乳动物
基因座。它们还扩展了与
胆固醇代谢异常相关的表型谱。