Astete C, Youlton R, Castillo S, Be C, Daher V
Departamento de Medicina, Hospital Clínico, Universidad de Chile.
Rev Chil Pediatr. 1991 Mar-Apr;62(2):99-102.
Among 257 patients with clinical diagnosis of Down's syndrome, 56.4% of male gender, in whom cytogenetic studies were performed, 14 (5.4%) had normal karyotypes and 243 (94.6%) had 21 trisomy. Of these last, 225 (92.6%) had free 21 trisomy, 10 (4.1%) showed mosaics, 8 (3.3%) had translocations. Average maternal age of this sample was significantly higher than that of patients attending the same maternity wards (32.14 vs. 24.85 years) and 41% of Down syndrome's patients came from mothers aged 36 years or more, even though only 9.7% of this country's deliveries proceed from women of that age group. As to seasonal occurrence, the proportions of births which happened in summer almost doubled that of winter (33.1% vs. 16.9%). The frequency of characteristic clinical signs of Down's syndrome was somewhat different than that described for patients from some other countries, for instance: epicanthus, short neck and widening of the space between 1st. and 2nd. toe were more frequent, while Brushfield's spots, depressed occiput, dental anomalies, heart malformations and fissured tongue seemed less frequent. The importance of cytogenetic studies for diagnosis and genetic counseling is stressed.
在257例临床诊断为唐氏综合征的患者中，进行细胞遗传学研究的男性患者占56.4%，其中14例（5.4%）核型正常，243例（94.6%）为21 - 三体。在这243例21 - 三体患者中，225例（92.6%）为游离型21 - 三体，10例（4.1%）为嵌合体，8例（3.3%）为易位型。该样本的母亲平均年龄显著高于在同一产科病房就诊的患者（32.14岁对24.85岁），41%的唐氏综合征患者来自36岁及以上的母亲，尽管该国只有9.7%的分娩是由该年龄组的女性进行的。关于季节性发病情况，夏季出生的比例几乎是冬季的两倍（33.1%对16.9%）。唐氏综合征特征性临床体征的频率与其他一些国家描述的患者有所不同，例如：内眦赘皮、短颈以及第一和第二脚趾间距离增宽更为常见，而Brushfield斑、枕骨凹陷、牙齿异常、心脏畸形和舌裂似乎不太常见。强调了细胞遗传学研究对诊断和遗传咨询的重要性。
