Diagnosed with GSD and PTEN hamartoma tumor syndrome, the patient underwent genetic analysis which identified two variants in lymphocyte–derived DNA: a germline heterozygous mutation c.517C>T (p.Arg173Cys) of the PTEN (Phosphatase And Tensin Homolog) gene and a polymorphism c.649-26G>T in the TSC2 (TSC Complex Subunit 2) gene. Here, PTEN is linked to disorder of glycogen metabolism.