Abstract
The glycogen storage diseases (GSDs) are a group of inherited metabolic disorders that result from a defect in any one of several enzymes required for either glycogen synthesis or glycogen degradation. The traditional diagnostic approach is based on the invasive hepatic or muscle biopsies, which are neither cost effective nor convenient. Molecular (gene testing) has emerged over the course of past few years as a robust alternative diagnostic tool, which not only confirms the diagnosis of GSDs but also clearly differentiates the types of GSDs allowing the initiation of the type-specific appropriate treatment for the particular type of GSDs. The aim of this update is to highlight the limitations of undertaking a liver biopsy for the diagnosis of GSDs; and to further describe the pros of the molecular testing for better patient centered care.