Clinical features and genetic analysis of one pedigree of glycogen storage disease type II

Abstract

Objective In order to improve the clinician’s awareness of the importance of early diagnosis of glycogen storage disease type Ⅱ，we reported a rare pedigree of glycogen storage disease type Ⅱ and summarized the clinical characteristics of it. Methods Clinical data of three patients in a family with juvenile glycogen storage disease type Ⅱ were collected and peripheral blood acid alphaglucosidase (GAA) activity testing and GAA gene sequencing were performed. Results Three patients (one male and two females) with typical clinical manifestations of the glycogen storage disease type Ⅱ were identified.They all manifested progressive proximal limb weakness with age at onset being 16，17 and 12 years old in Ⅱ1，Ⅱ3 and Ⅱ7，respectively. Ⅱ7 and Ⅱ3 manifested severe respiratory muscles weakness，respiratory failure and ventilator dependency survival at an earlier onset. Ⅱ1 also manifested moderate respiratory muscles weakness early.The increase of creatine kinase in Ⅱ7 and Ⅱ3 was mild to moderate. The GAA activity of the three patients was significantly lower than normal. A nonsense mutation of c.241C>T (p.Gln81X) in exon 2 and a missense mutation of c.2238G>C (p.Trp746Cys) in exon 16 were detected in all of the three patients. Conclusions GAA activity and GAA genetic testing are very important for early diagnosis of glycogen storage disease type Ⅱ and are helpful for clear diagnosis，carriers，genetic counseling and prenatal diagnosis. Key words: Glycogen storage disease type Ⅱ; Early diagnosis; alpha-Glucosidases; Mutation; Pedigree