Melkild A
Barnepsykiatrisk avdeling Haukeland Sykehus, Bergen.
Tidsskr Nor Laegeforen. 1994 Jan 10;114(1):36-8.
Ring chromosome 21 is a very rare chromosomal abnormality known to cause a great variety of clinical findings. Persons with ring chromosome 21 can be intellectually and phenotypically normal, but this abnormality is found more often in persons with dysmorphic features, malformations and mental retardation. Ring chromosome 21 is also encountered as the only chromosomal abnormality in individuals with Down syndrome. We describe a four year old girl with ring chromosome 21 (karyotype 46,XX/46,XX,-21, +r(21)), who was examined in a department of child psychiatry because of delayed development. The child had serious speech and language problems, slightly dysmorphic features and bilateral hip-joint dysplasia.
21号环状染色体是一种非常罕见的染色体异常，已知会导致各种各样的临床症状。患有21号环状染色体的人在智力和表型上可能是正常的，但这种异常在具有畸形特征、畸形和智力迟钝的人中更为常见。21号环状染色体在唐氏综合征患者中也作为唯一的染色体异常出现。我们描述了一名患有21号环状染色体（核型46,XX/46,XX,-21,+r(21)）的4岁女孩，她因发育迟缓在儿童精神科接受检查。该儿童有严重的言语和语言问题、轻微的畸形特征和双侧髋关节发育不良。
