一个非综合征手足裂畸形家系的临床调查及遗传学分析

目的分析一先天性手足裂伴并指／趾畸形家系的临床表现,并从分子水平查找致病原因,为罹患家庭提供遗传咨询。方法通过X线检查资料及手足裂外观照片,对家系3代现存3例患者（共4例患者）进行临床分析,对3例患者用常规方法制备外周血淋巴细胞染色体标本,进行G显带核型分析。从7名家系成员（包含3例患者）外周血样品中提取基因组DNA。针对p63基因全部15个外显子及删rJ0b基因5个外显子进行引物设计合成、PCR扩增、回收纯化并测序。结果家系中现存3名患者均表现为双手中央分裂,其中1例患者双足呈楔形裂开,2例患者右足均为第3、4趾并指,皮肤黏连;G显带核型分析未发现染色体畸变;p63基因未检测到突变,删rJ0b基因的外显子5a中发现一个碱基突变c．1058C〉T。结论通过家系内息者临床表型分析,可将该疾病类型确定为非综合征手足裂畸形,且临床症状逐代加重。测序结果提示p63基因和删rJ0b基因关键区域内的点突变都不是引起该家系手足裂畸形的原因。

Clinical investigation and genetical analysis of a family with non-syndromic split-hand/split-foot malformation

Objective To identify the clinical symptoms and find the pathogeny of split-hand/ split-foot malformation （SHFM） for a Chinese family. Methods Three out of four affected patients in one three-generation Chinese pedigree SHFM family were examined of the malformed hands and feet obser- vation by digital photographs and X-ray. Peripheral blood samples were collected from three affected pa- tients followed by lymphocytes G banding assay. Genomic DNA was extracted from the whole blood samples of 7 available family members, including the three affected patients. All 15 exons of the p63 and 5 exons of the WNTIOb were amplified by polymerase chain reaction （PCR） and followed by purification and gene sequencing. Results All three existing affected patients showed absence of the third radial fingers in their hands, one affected patient had a deep central cleft and central ray deficiency in his feet, and two affectedpatients had a soft-tissue syndactyly between the 3~ and 4th toes of the right foot. G banding assay showed that normal karyotypes in the three affected patients and invisible cytogenetic abnormality was found. More- over, no mutation was found in the coding region of p63 gene. However, a mutation from C to T was oberserved at the exon 5 a in WNT10b gene （c. 1058 C 〉 T）. Conclusion This case is a rare condi- tion characterized by non-syndromic SHFM and the phenotype got worse with the generations. In the cur- rent study, we concluded that the point mutation of gene p63 and WNTIOb may not the cause of non- syndromic SHFM in this family.