Department of Neurosurgery, Center for Human Genetics and Genomics, and Program on Neurogenetics, Yale School of Medicine, New Haven, CT 06510, USA.
Am J Hum Genet. 2011 May 13;88(5):523-35. doi: 10.1016/j.ajhg.2011.03.019. Epub 2011 Apr 28.
We investigated three families whose offspring had extreme microcephaly at birth and profound mental retardation. Brain scans and postmortem data showed that affected individuals had brains less than 10% of expected size (≤10 standard deviation) and that in addition to a massive reduction in neuron production they displayed partially deficient cortical lamination (microlissencephaly). Other body systems were apparently unaffected and overall growth was normal. We found two distinct homozygous mutations of NDE1, c.83+1G>T (p.Ala29GlnfsX114) in a Turkish family and c.684_685del (p.Pro229TrpfsX85) in two families of Pakistani origin. Using patient cells, we found that c.83+1G>T led to the use of a novel splice site and to a frameshift after NDE1 exon 2. Transfection of tagged NDE1 constructs showed that the c.684_685del mutation resulted in a NDE1 that was unable to localize to the centrosome. By staining a patient-derived cell line that carried the c.83+1G>T mutation, we found that this endogeneously expressed mutated protein equally failed to localize to the centrosome. By examining human and mouse embryonic brains, we determined that NDE1 is highly expressed in neuroepithelial cells of the developing cerebral cortex, particularly at the centrosome. We show that NDE1 accumulates on the mitotic spindle of apical neural precursors in early neurogenesis. Thus, NDE1 deficiency causes both a severe failure of neurogenesis and a deficiency in cortical lamination. Our data further highlight the importance of the centrosome in multiple aspects of neurodevelopment.
我们研究了三个家庭，他们的后代在出生时患有严重的小头畸形和严重的智力迟钝。脑部扫描和死后数据显示，受影响的个体的大脑小于预期大小的 10%（≤10 个标准差），并且除了神经元生成大量减少外，他们还表现出皮质层状结构部分缺陷（微小脑回畸形）。其他身体系统显然没有受到影响，整体生长正常。我们在一个土耳其家庭中发现了两个不同的 NDE1 纯合突变，c.83+1G>T（p.Ala29GlnfsX114），在两个巴基斯坦裔家庭中发现了 c.684_685del（p.Pro229TrpfsX85）。使用患者细胞，我们发现 c.83+1G>T 导致使用新的剪接位点，并在 NDE1 外显子 2 后发生移码。转染标记的 NDE1 构建体表明，c.684_685del 突变导致 NDE1 无法定位到中心体。通过染色携带 c.83+1G>T 突变的患者来源细胞系，我们发现这种内源性表达的突变蛋白同样无法定位到中心体。通过检查人类和小鼠胚胎大脑，我们确定 NDE1 在发育中的大脑皮层神经上皮细胞中高度表达，特别是在中心体中。我们表明，NDE1 在早期神经发生中在上皮前体细胞的有丝分裂纺锤体上积累。因此，NDE1 缺乏会导致神经发生严重失败和皮质层状结构缺陷。我们的数据进一步强调了中心体在神经发育多个方面的重要性。
