Fineman R M, Ablow R C, Howard R O, Albright J, Breg W R
Pediatrics. 1975 Nov;56(5):762-7.
Chromosome 8 is the largest autosome thus far found to be trisomic among liveborn infants. Trisomy 8 "mosaicism" syndrome (T8mS) consists primarily of individuals whose chromosome complement is mosaic for chromosome 8 (T8m), i.e., patients with a chromosomally normal cell line in addition to the trisomic 8 cell line, and a few known individuals with full trisomy 8 (T8), i.e., each cell observed contains an extra chromosome 8. Reported cases of both types share a number of common features and thus have helped to delineate a new syndrome. Common features of T8mS include mild-to-moderate mental retardation, strabismus, osseous and soft tissue abnormalities, lowset and/or malformed ears, broad bulbous nose, palate deformity, various types of congenital cardiovascular disorders, hydronephrosis, cryptorchidism, and characteristic dermatoglyphics. Since chromosomal mosaicism is often present in this syndrome it is not surprising that considerable phenotypic variation exists. The present report of one of the youngest individuals yet described with T8m adds two more physical findings (dense corneal clouding and a heretofore undescribed clavicular deformity) to the constellation of abnormalities associated with T8mS. On the basis of the phenotypic and cytogenetic findings in this and 17 similar patients previously reported it is proposed that T8mS is a distinct clinical entity.
8号染色体是迄今为止在活产婴儿中发现的三体性最大的常染色体。8号染色体“嵌合”综合征（T8mS）主要由染色体组成是8号染色体嵌合体（T8m）的个体构成，即除了三体8细胞系外还有染色体正常细胞系的患者，以及少数已知的完全三体8（T8）个体，即观察到的每个细胞都含有一条额外的8号染色体。这两种类型的报告病例都有许多共同特征，因此有助于界定一种新的综合征。T8mS的共同特征包括轻至中度智力发育迟缓、斜视、骨骼和软组织异常、低位和/或畸形耳、宽球根状鼻、腭裂、各种类型的先天性心血管疾病、肾积水、隐睾症以及特征性皮纹。由于该综合征中常存在染色体嵌合现象，所以存在相当大的表型变异也就不足为奇了。本报告中描述的最年轻的T8m个体之一，在与T8mS相关的异常情况中又增加了两项体格检查发现（致密性角膜混浊和一种此前未描述的锁骨畸形）。根据本病例以及之前报告的17例类似患者的表型和细胞遗传学发现，提出T8mS是一种独特的临床实体。
