Glycogen synthase deficiency (also known as GSD type 0B) is an ultra-rare form of muscle glycogenosis first described in 2007 and linked to mutations in the GYS1 gene. An Italian team reports the clinical and genetic data of two new cases from unrelated families:
- unlike the original cases, the picture included muscle deficit, myalgic syndrome and fatigability but no cardiomyopathic involvement;
- the disorders appeared in adulthood and progressed little over time;
- the diagnosis was evoked on the basis of muscle biopsy data (almost complete glycogen depletion) and then confirmed by molecular biology with homozygous pathological variants (different in both cases) in the GYS1 gene.
