Infantile and adult-onset acid maltase deficiency occurring in the same family.

A 16-week-old girl died from the infantile form of acid maltase deficiency (Pompe disease, acid alpha-glucosidase deficiency). Her paternal grandfather was well until the age of 53 years, when he started to suffer from the adult-onset form of the same enzyme deficiency. This observation suggests that the infantile and adult-onset forms of acid maltase deficiency are genetically related.