Juvenile onset acid maltase deficiency presenting as a rigid spine syndrome

The rigid spine syndrome is a disorder characterized by proximal muscle weakness and limitation in flexion of the cervical and dorsolumbar spine. Such phenotype may be caused by a variety of hereditary myopathies. We present the case of a 15-years-old boy with rigid spine syndrome and severe restrictive respiratory changes. Muscle biopsy revealed vacuolar myopathy with excessive deposition of PAS-positive material. Lysosomal acid maltase activity in cultured skin fibroblasts was reduced to 6% of control values. DNA analysis demonstrated novel mutation E888X of acid α-glucosidase gene with compound heterozygosity IVS1/E888X, confirming diagnosis of Pompe disease. We conclude that acid maltase deficiency should be considered in the diagnosis of rigid spine syndrome.