一个X连锁迟发性脊椎骨骺发育不良家系TRAPPC2基因的突变研究

Mutation analysis of the TRAPPC2 gene in a Chinese family with X-linked spondyloepiphyseal dysplasia tarda

目的确定一个X连锁迟发性脊椎骨骺发育不良（X-linked spondyloepiphyseal dysplasia tarda，x-sEDL）家系TRAPPC2基因的突变类型，并探讨该家系发病的分子遗传学机制。方法采集该家系32名成员及50名正常成年人对照者的外周血样，提取基因组DNA。采用聚合酶链反应扩增TRAPPc2基因第3～6外显子及侧翼区，对扩增产物进行双向直接测序，将测序结果与GenBank中的TRAPPC2的参考序列进行比对，以确定突变位点及类型。结果在先证者TRAPPC2基因第3内含子剪接供体处发现一个c．93＋5G〉A突变，TRAPPC2基因第3～6外显子的核苷酸序列未见改变。该家系成员中，6例男性患者、8例女性携带者均检出同一突变，在其余表型正常的18名成员及正常对照者中未发现该突变。结论在中国的ⅪsEDL患者中发现了TRAPPc2基因的C．93＋5G〉A突变，丰富了TRAPPC2基因的突变谱。上述检测将有助于对X—SEDL进行症状前诊断及产前诊断。

Objective To identify potential mutation of TRAPPC2 gene in a Chinese family affected with X-linked spondyloepiphyseal dysplasia tarda （X-SEDL）, and explore its underlying molecular mechanism. Methods Peripheral blood samples were collected from 32 members of the family and 50 healthy adults to extract genomic DNA. DNA sequences of exons 3 to 6 and their exon/intron boundaries were amplified with PCR amplification. Direct hi-directional sequencing analysis was performed on the PCR products. The sequences were aligned to the reference sequences from the GenBank to determine mutation site and type. Results A nucleotide substitution of the splice-donor in TRAPPC2 intron 3, e. 93q-5G〉 A, was detected in the proband, but no sequence change was detected in TRAPPC2 exons 3 to 6. All of the 6 male patients and 8 female carriers from the family were detected to have carried this mutation. The same mutation was not found in the remaining 18 family members with a normal phenotype and 50 healthy controls. Conclusion We have detected a c. 93-1-5G〉A mutation in the TRAPPC2 gene in a Chinese family affected with X- SEDL. Our results have expanded the spectrum of TRAPPC2 mutations and is helpful for presymptomatic and prenatal diagnoses of this disease.