一例糖原累积病Ⅵ型患儿的PYGL基因变异分析

Genetic analysis of PYGL gene variants for a child with Glycogen storage disease-Ⅵ

目的分析1例糖原累积病Ⅵ型(glycogen storage disease typeⅥ,GSD-Ⅵ)患儿的临床特征和基因变异情况,明确其致病原因。方法收集1例GSD-Ⅵ患儿的临床资料,采集患儿及其父母外周血提取基因组DNA,应用全外显子测序对患者进行基因检测,对疑似变异进行Sanger测序验证并行生物信息学分析。结果患儿表现为空腹低血糖、肝大、生长迟缓、转氨酶增高、代谢性酸中毒、高乳酸,肝穿刺病理提示糖原累积病。基因测序提示患儿PYGL基因存在c.2089A>G(p・Asn697Asp)和c.158_160delACT(p.Tyr53del)复合杂合变异。Sanger测序验证提示患儿母亲存在c.2089A>G杂合变异,患儿父亲存在c.158_160delACT杂合变异。这两种变异均为罕见的变异,既往未见报道,其位点高度保守且Provean、MutationTaster预测为有害。结论PYGL基因复合杂合变异(c.2089A>G/c.158_160delACT)为患儿的致病原因。新变异位点的检出丰富了PYGL基因的变异谱,为该家系的遗传咨询提供了依据。

Objective To explore the clinical features and genetic basis of a patient with glycogen storage disease typeⅥ(GSD-Ⅵ).Methods Clinical data of the patient was collected.Genomic DNA was extracted from peripheral blood samples of the proband and his parents.Genetic variants were detected by using whole exome sequencing.Candidate variants were verified by Sanger sequencing followed by bioinformatics analysis.Results The proband presented fasting hypoglycemia,hepatomegaly,growth retardation>transaminitis,metabolic acidosis and hyperlactatemia.Liver biopsy indicated GSD.Novel compound heterozygous PYGL gene variants(c.2089A>G/c.158_160delACT)were detected in the proband.Compound heterozygosity was confirmed by Sanger sequencing of the patient's genomic DNA.Provean and MutationTaster predicted the two variants as deleterious and the variant sites as highly-conserved.Conclusion The compound heterozygous variants(c.2089A>G/c.158_160delACT)of PYGL gene probably underlay the GSD in this patient.The two novel variants have expanded the spectrum of PYGL gene variants and provided the basis for genetic counseling of the family.