Cai T, Yu P, Tagle D A, Xia J
National Laboratory of Medical Genetics, Hunan Medical University, P. R. China.
Am J Med Genet. 1999 Oct 8;86(4):305-11.
We describe a 1-year-old boy with mental and physical retardation, a large anterior fontanel, brachycephaly with flat occiput, short and stubby fingers, generalized hypotonia, ocular hypertelorism, low-nasal bridge, long philtrum, high-narrow palate, apparently low-set ears, and a small mandible. Cytogenetic analysis utilizing high resolution chromosome banding technique showed an unbalanced karyotype consisting of 46,XY,add(21)(q22.3) that originated from maternal balanced translocation between chromosomes 7 and 21. Fluorescence in situ hybridization (FISH) using micro-dissected library probe pool from chromosome 7 confirmed the additional material on 21q was derived from chromosome 7. Our results indicated that the patient had an unbalanced translocation, 46,XY, der(21)t(7;21)(p21.2;q22.3)mat, which resulted in duplication for distal 7p. Our patient is similar to reported cases with a 7p15-->pter or larger duplication of 7p, suggesting that the critical segment causing the characteristic phenotype of 7p duplication syndrome, including large anterior fontanel, exists at 7p21.2 or 7p21.2-->pter.
我们描述了一名1岁男孩，有智力和身体发育迟缓、前囟门大、扁头畸形伴枕骨扁平、手指短粗、全身肌张力低下、眼距增宽、鼻梁低、人中长、高窄腭、耳低位明显以及下颌小。利用高分辨率染色体显带技术进行的细胞遗传学分析显示核型不平衡，为46,XY,add(21)(q22.3)，起源于母亲7号和21号染色体之间的平衡易位。使用来自7号染色体的微切割文库探针池进行荧光原位杂交（FISH）证实21q上的额外物质来自7号染色体。我们的结果表明该患者存在不平衡易位，即46,XY, der(21)t(7;21)(p21.2;q22.3)mat，导致7p远端重复。我们的患者与报道的7p15→pter或更大范围7p重复的病例相似，提示导致7p重复综合征特征性表型（包括前囟门大）的关键片段位于7p21.2或7p21.2→pter。
