Isaac G S, Krishnamurty P S, Reddy Y R, Ahuja Y R
Institute of Genetics, Hospital for Genetic Diseases, Osmania University, Hyderabad, India.
Acta Anthropogenet. 1985;9(4):256-60.
A cytogenetic analysis of Down's syndrome revealed straight trisomy 21 in 96.5 per cent affected. Remaining 3.5 per cent were found to have chromosomal mosaicism. In addition, a normal karyotype was observed in 2 individuals with Down's phenotype. A survey of Down's syndrome in Hyderabad gave an incidence of 1.17 per 1000 or 1 in 853 live births. There was a significant increase in the mean maternal age of the affected over the controls. Sex ratio was also higher in our sample of Down's syndrome as compared to the general population.
对唐氏综合征的细胞遗传学分析显示，96.5%的患者为21号染色体单纯三体性。其余3.5%被发现存在染色体嵌合现象。此外，在2名具有唐氏综合征表型的个体中观察到正常核型。对海得拉巴市唐氏综合征的一项调查得出，发病率为每1000例中有1.17例，即853例活产中有1例。与对照组相比，患者的平均母亲年龄显著增加。与一般人群相比，我们的唐氏综合征样本中的性别比也更高。
