Garabedian B H, Fraser F C
Centre for Human Genetics, McGill University, Montreal, Quebec, Canada.
J Med Genet. 1993 Oct;30(10):849-51. doi: 10.1136/jmg.30.10.849.
It has been suggested that neural tube defects (NTDs) of the upper type (anencephaly, encephalocele, and thoracic spina bifida) may have a pathogenesis different from those of the lower type (lumbosacral spina bifida), since recurrent cases within a sibship were said always to be concordant with respect to NTD type. Also, spontaneous abortion, additional malformation, and recurrence rate were observed to be higher in the upper group, and there was an excess of females in upper NTD probands. To test this hypothesis, we measured the above variables in upper and lower NTDs in a sample from Quebec. We found less than full concordance (50%) of NTD type in 18 sib pairs. Recurrence rate was not significantly lower in the lower NTD group (5.6 v 5.8%). The other variables were in general agreement with previous studies, inconsistent findings possibly attributable to different NTD population incidences. These findings can be accounted for if upper and lower NTDs share a similar pathogenesis and the embryo is more susceptible during early than late neural tube formation.
有人提出，上型神经管缺陷（无脑儿、脑膨出和胸段脊柱裂）的发病机制可能与下型（腰骶部脊柱裂）不同，因为据说同胞亲属中的复发病例在神经管缺陷类型方面总是一致的。此外，上型组的自然流产、合并其他畸形和复发率更高，并且上型神经管缺陷先证者中女性过多。为了验证这一假设，我们在魁北克的一个样本中对上型和下型神经管缺陷测量了上述变量。我们发现18对同胞中神经管缺陷类型的一致性不到完全一致（50%）。下型神经管缺陷组的复发率没有显著降低（5.6%对5.8%）。其他变量总体上与先前的研究一致，不一致的结果可能归因于不同的神经管缺陷人群发病率。如果上型和下型神经管缺陷具有相似的发病机制，并且胚胎在神经管形成早期比晚期更易受影响，那么这些发现就可以得到解释。
