A rare case of infantile onset Pompe disease with genetic diagnosis

Abstract

Glycogen storage disease type II, also called Pompe disease or acid maltase deficiency is a disorder of muscle glycogenoses with a wide range of clinical manifestations. It is one of the disorders of glycogen metabolism caused by a deficiency of lysosomal acid α-1, 4-glucosidase (acid maltase) resulting in lysosomal glycogen accumulation in cardiac, skeletal and smooth muscle cells. The pattern of inheritance is autosomal recessive with a gene for enzyme located on chromosome 17q25.2.It is the first recognized lysosomal storage disorder and the first neuromuscular disorder for which enzyme replacement therapy has been approved. We report a case of four month old female child, born to primi gravida third degree consanguineous couple, who presented with history of respiratory illness, hypotonia and developmental delay. Baby was sick needing mechanical ventilation and inotropic support. Echocardiography showed concentric LV hypertrophy with no LV outflow tract obstruction. In view of consanguinity, developmental delay, hepatomegaly and cardiomegaly, provisional diagnosis of a storage disorder, probably infantile Pompe disease was considered. Dried blood spot for α-1, 4-glucosidase enzyme assay confirmed the same. Enzyme replacement therapy was considered, but child progressed to cardiac failure needing prolonged ventilation and expired on day 8 of admission. Whole genome exome sequencing revealed 2 mutations which confirmed the diagnosis. Infantile Pompe disease is fatal without treatment. High index of suspicion and early diagnosis may help in taking advantage of emerging therapeutics, such as ERT which is capable of changing the natural history of the disease.