An Unusual Case of Neonatal Hypotonia and Femur Fracture: Neuromuscular Variant of Glycogen Storage Disease Type IV

Glycogen storage disease type IV (GSD IV) (OMIM #232500) is an autosomal recessive disorder caused by deficiency of the glycogen-branching enzyme. Here, we report a patient presenting with prematurity and severe hypotonia resulting from complicated pregnancy polyhydramnios. During her stay in neonatal unit, infant remained dependent on ventilator, movements were mostly absent, except for occasional small fingers. A spontaneous fracture femur shaft occurred postnatal fourth week. Whole-exome sequencing DNA revealed homozygous missense variant GBE1 gene (c.1693C>T, p.Arg565Trp). The variation detected index case was also confirmed Sanger respective parents. This study showed that neuromuscular subtypes GSD-IV should be considered as possible differential diagnosis cases.