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目的研究家族性颅锁骨发育不全家系基因型与临床表型的关系。方法提取临床收集的一个先天性颅锁骨发育不全家系中患者和健康成员外周血基因组DNA,PCR扩增RUNX2/CBFA1基因7个编码外显子及其侧翼内含子序列,分别进行正反向测序,对发现的突变位点行酶切分析验证。结果家系中两位患者(先证者及其父亲)显示cDNA 346T→A的杂合突变,使编码的色氨酸变成精氨酸(W 116R),属错义突变。酶切结果进一步证实了该错义突变。测序还发现先证者父亲cDNA 198G→A的杂合突变,致第66位氨基酸的密码子GCG被GCA取代,但二者均编码丙氨酸,属同义突变。先证者及家系健康成员中未见此改变。结论 RUNX2/CBFA1基因346T→A杂合突变是该家系发病的分子基础。
Objective To study the relationship between genotypes and clinical phenotypes in familial CSP. Methods Genomic DNA from peripheral blood of patients with congenital cranial clavicular dysplasia and congenital ankle hypoplasia collected from clinics was extracted. Seven coding exons of RUNX2 / CBFA1 gene and their flanking intron sequences were amplified by PCR. The positive and negative Sequencing and identification of the mutation sites identified by enzyme digestion. Results Two patients in the pedigree (probands and their fathers) showed a heterozygous mutation in cDNA 346T → A, encoding a tryptophan to arginine (W 116R). Cleavage results further confirmed the missense mutation. Sequencing also found heterozygous mutation of cDNA 198G → A in the father of the proband, resulting in the GCG substitution of the codon 66 of the amino acid at codon 66, both of which encode alanine, which are synonymous mutations. No change has been seen in probands and family members. Conclusion The 346T → A heterozygous mutation of RUNX2 / CBFA1 gene is the molecular basis of the pedigree.