两例46,XY同患17α-羟化酶缺陷症家系的临床和分子遗传学研究

目的 对一个有两例46,XY同患17α-羟化酶缺陷症的家系进行临床、生化和分子生物学研究,探讨纯合突变和杂合突变在促肾上腺皮质激素(ACTH)兴奋实验前后相关生物学指标的改变.方法 收集一个17α-羟化酶缺陷症家系患者及其他成员的临床和实验室资料,采用PCR产物直接测序方法检测17α-羟化酶基因(CYP17A1)序列;进行1h ACTH兴奋试验.结果 患者CYP17A1基因第6号外显子329位密码子发生了TAC329AA纯合突变,引起Tyr329Lys错义突变和以后的移码突变;携带该突变基因的杂合子在ACTH兴奋前后激素水平的变化介于纯合基因型与正常对照之间.结论 本研究家系中CYP17A1基因突变是17α-羟化酶缺陷症的致病基因,携带该突变基因的杂合子能导致一定程度的生物学功能变化.

A clinical and genetic analysis of a pedigree with two 46,XY patients suffering from 17α-hydroxylase deficiency

Objective To investigate the molecular defects of CYPl7A1 gene in a pedigree with two 46,XY patients suffering from 17α-hydroxylase deficiency (17-OHD) and explore the steroid biosynthetic difference in carriers of 17-OHD before and after adrenocorticotrophic hormone (ACTH) test.Methods Clinical data and hormone profiles were collected from the members of the pedigree.CYPl7A1 genotyping was performed in the patients and family members with PCR-direct sequencing.A short ACTH test was evaluated in some cases.Results The CYP17 genes of the patients were proved to hold a homozygous mutation with a base deletion and a base transversion (TAC/AA) in exon 6,which produced a missense mutation of Tyr→ Lvs at codon 329 and changed the open reading frame following this codon.The hormone response of the carriers after ACTH stimulation was abnormal between the patients and normal controls.Conclusion 17-OHD in this family was caused by CYP17A1 mutation (TAC329AA):some hormonal response to ACTH stimulation Was abnormal in carriers.