Infantile cardiomyopathy and neuromyopathy with β-galactosidase deficiency

We observed an infant with congenital cardiomyopathy, muscular weakness and hypotonia, who developed hepatosplenomegaly and died from heart failure at the age of 8 months. His condition (including electromyographic findings) resembled infantile Pompe disease but was different by echocardiography, morphology of lymphocyte inclusions, and enzymatic studies demonstrating an almost total deficiency of -galactosidase activity towards methylumbelliferyl substrate in leucocytes, plasma and fibroblasts. His parents had about half the normal activities in leucocytes and plasma. Whilst -galactosidase deficiency in an infantile storage disorder is characteristic of generalized (type 1) GM₁-gangliosidosis, this patient differed by the striking involvement of the cardiac and skeletal muscles and the lack of facial and osseous changes. This case and a similar one reported underlines the necessity to consider storage disorders apart from glycogenosis in congenital cardiomyopathy.