Early onset neutral lipid storage disease with myopathy presenting as congenital hypotonia and hepatomegaly

Abstract

Neutral lipid storage disease with myopathy is an ultra-rare, inherited autosomal recessive neuromuscular metabolic disorder caused by pathogenic variants in PNPLA2. It typically presents in adults as a progressive myopathy and is associated with myocardiopathy, hepatic involvement, and high creatine kinase levels. Only three children and adolescents with neutral lipid storage disease with myopathy have been reported. We report a female infant with congenital hypotonia born to consanguineous parents, whose mother presented with polyhydramnios during pregnancy. She demonstrated delayed acquisition of motor milestones, hepatomegaly, and elevated creatine kinase levels. Homozygous pathogenic variants in PNPLA2 were identified. Lipid accumulation was observed within the muscle fibers and Jordans' anomaly was observed in a blood smear. This is the first report to describe an infant with mildly symptomatic neutral lipid storage disease with myopathy and demonstrate hepatic involvement in a pediatric patient. Despite her mild symptoms, her ancillary test results were markedly abnormal.

Keywords: Fatty liver; Hepatomegaly; Lipid droplets; Lipid metabolism disorders; Muscle hypotonia; Neutral lipid storage disease with myopathy.