Lee M, Rose D, Lazzarini A, Rajendra B R, Sciorra L J
Hum Genet. 1979 Oct 2;51(3):343-7. doi: 10.1007/BF00283407.
Monosomy 21, whether homogeneous or as a mosaicism, is very uncommon. We report here a 3-month-old white female with a low degree of monosomy 21 in the blood karyotype (6.5%, 110 cells counted) but not in the skin fibroblasts, which contained only the normal chromosome complement. The patient's physical features included microcephaly with frontal slanting; prominent occiput; ridge-shaped sutures; agenesis of the corpus callosum; large, prominent ears; high and narrow palate; micrognathia; tetralogy of Fallot; crowded toes; and dry, thick skin with very little subcutaneous tissue. The case is discussed in light of the suggested clinical features of the "monosomy 21" syndrome and the possible implications of such a low-grade mosaicism in prenatal diagnosis.
21号染色体单体，无论是纯合型还是嵌合型，都非常罕见。我们在此报告一名3个月大的白人女性，其血液核型中存在低比例的21号染色体单体（6.5%，共计数110个细胞），但皮肤成纤维细胞中未发现，其仅含有正常的染色体组。患者的身体特征包括小头畸形伴额部倾斜；枕部突出；嵴状缝线；胼胝体发育不全；大而突出的耳朵；高而窄的腭；小颌畸形；法洛四联症；脚趾拥挤；以及干燥、厚实且几乎没有皮下组织的皮肤。根据“21号染色体单体”综合征的推测临床特征以及这种低级别嵌合在产前诊断中的可能影响对该病例进行了讨论。
