Trioche P, Francoual J, Audibert F, Chalas J, Lindenbaum A, Odièvre M, Labrune P
Service de Pédiatrie, Hôpital Antoine Béclère, Clamart, France.
Prenat Diagn. 1998 Jun;18(6):629-31.
Glycogen storage disease type Ia (GSD Ia) is an autosomal recessive condition, caused by a deficiency of hepatic glucose-6-phosphatase (G6Pase) activity. In a consanguineous family originating from northern Africa whose first daughter was affected with GSD Ia, we were able to identify the disease-causing mutation, a cytosine to thymine substitution at nucleotide 326 in exon 2 of the G6Pase gene (R83C). This mutation causes the disappearance of an HgaI site, and is thus easily detectable by restriction enzyme digestion. Both parents were heterozygous for this mutation. During the third pregnancy, fetal genomic DNA was extracted from a chorionic villus biopsy sampled at the 24th week of gestation. Exons 2 of the G6Pase gene were amplified by the polymerase chain reaction followed by HgaI digestion. Fetal DNA analysis indicated that the fetus had received both normal G6Pase alleles. This result was confirmed after birth. DNA analysis is the only reliable method for prenatal diagnosis of GSD Ia.
糖原贮积病Ia型（GSD Ia）是一种常染色体隐性疾病，由肝脏葡萄糖-6-磷酸酶（G6Pase）活性缺乏引起。在一个来自北非的近亲家庭中，其长女患有GSD Ia，我们能够鉴定出致病突变，即G6Pase基因第2外显子第326位核苷酸处的胞嘧啶到胸腺嘧啶的替换（R83C）。该突变导致一个HgaI位点消失，因此通过限制性酶切很容易检测到。父母双方均为该突变的杂合子。在第三次怀孕时，从妊娠第24周采集的绒毛膜绒毛活检样本中提取胎儿基因组DNA。通过聚合酶链反应扩增G6Pase基因的第2外显子，随后进行HgaI酶切。胎儿DNA分析表明胎儿获得了两个正常的G6Pase等位基因。出生后这一结果得到了证实。DNA分析是GSD Ia产前诊断的唯一可靠方法。
