Karadima G, Bugge M, Nicolaidis P, Vassilopoulos D, Avramopoulos D, Grigoriadou M, Albrecht B, Passarge E, Annerén G, Blennow E, Clausen N, Galla-Voumvouraki A, Tsezou A, Kitsiou-Tzeli S, Hahnemann J M, Hertz J M, Houge G, Kuklík M, Macek M, Lacombe D, Miller K, Moncla A, López Pajares I, Patsalis P C, Petersen M B
Department of Genetics, Institute of Child Health, Athens, Greece.
Eur J Hum Genet. 1998 Sep-Oct;6(5):432-8. doi: 10.1038/sj.ejhg.5200212.
Causes of chromosomal nondisjunction is one of the remaining unanswered questions in human genetics. In order to increase our understanding of the mechanisms underlying nondisjunction we have performed a molecular study on trisomy 8 and trisomy 8 mosaicism. We report the results on analyses of 26 probands (and parents) using 19 microsatellite DNA markers mapping along the length of chromosome 8. The 26 cases represented 20 live births, four spontaneous abortions, and two prenatal diagnoses (CVS). The results of the nondisjunction studies show that 20 cases (13 maternal, 7 paternal) were probably due to mitotic (postzygotic) duplication as reduction to homozygosity of all informative markers was observed and as no third allele was ever detected. Only two cases from spontaneous abortions were due to maternal meiotic nondisjunction. In four cases we were not able to detect the extra chromosome due to a low level of mosaicism. These results are in contrast to the common autosomal trisomies (including mosaics), where the majority of cases are due to errors in maternal meiosis.
染色体不分离的原因是人类遗传学中尚未解决的问题之一。为了增进我们对不分离潜在机制的理解，我们对8号染色体三体和8号染色体三体镶嵌现象进行了分子研究。我们报告了使用沿8号染色体长度定位的19个微卫星DNA标记对26名先证者（及其父母）进行分析的结果。这26个病例包括20例活产、4例自然流产和2例产前诊断（绒毛取样）。不分离研究结果表明，20例（13例母亲来源、7例父亲来源）可能是由于有丝分裂（合子后）复制，因为观察到所有信息性标记均纯合化，且从未检测到第三个等位基因。仅2例自然流产病例是由于母亲减数分裂不分离。在4例病例中，由于镶嵌现象水平较低，我们未能检测到额外的染色体。这些结果与常见的常染色体三体（包括镶嵌体）相反，后者大多数病例是由于母亲减数分裂错误所致。
