An ultra-rare cause of severe hypotonia mimickingPompe disease in an infant: RRM2B related mitochondrial DNA depletion syndrome with a novel mutation

[摘要] Ribonucleotide-diphosphate reductase subunit M2B(RRM2B)-related mitochondrial disease is one ofthe ultra-rare mitochondrial depletion syndromes. A-2-months of age girl who had severe hypotoniawith absent reflexes, failure to thrive, and developmental delay was hospitalized under our care. Theinitial diagnosis was Pompe disease with absent reflexes and increased creatine kinase level. Enzymeanalysis for Pompe disease was normal and next-generation sequence panel analysis of 450 genesrelated to metabolic disorders revealed a novel mutation in the RRM2B gene. The patient died at theage of 2.5 months. Up to date, there have been reports of 31 patients with infantile forms of RRM2B.This patient presented with little features to suggest a mitochondrial disorder. In conclusion, RRM2Bmutations should be included in the differential diagnosis of the Pompe disease in infants with severehypotonia. This case report also expands the mutation spectrum of rare infantile form of the RRM2Bmutations.

[学科分类] 精神健康和精神病学

[关键词] Pompe disease;mimicking;hypotonia;elevated creatine kinase;RRM2B mutations;absentreflexes;lactic acidosis