Glycogenoses are rare and heterogeneous pathologies, both clinically and genetically. By definition, they are related to a disorder of glycogen metabolism (glycogen accumulation), the latter plays an essential role in glycogen storage that is required for cellular energy. They can have muscular, but also cardiac and/or hepatic manifestations. Besides the more frequent and better described, such as maltase deficiency (or Pompe disease) or McArdle’s disease, rarer forms of glycogenoses have been reported in recent years.
In an article published in December 2017, French and Danish researchers whose work was supported by the AFM-Telethon, report the clinical and biological data of nine patients with a deficiency in the GYG1 gene, encoding glycogenin-1, an enzyme involved in glycogen synthesis (glycogenosis type XV, OMIM 613507). To date, it is the largest cohort of patients described for this form of glycogenosis, all corresponding to five families as well as six distinct mutations of the GYG1 gene. The phenotypic spectrum in this series is broader with clinical pictures that can mimic limb girdle muscular dystrophy (LGMD), as originally described in the literature, a scapulohumeral (which can suggest FSH) affection or distal myopathy. Histological examination maintains its diagnostic orientation in the presence of glycogen accumulation.
