Familial adult-onset Pompe disease associated with unusual clinical and histological features

The adult-onset form of Pompe disease had a wide clinical spectrum, ranging from asymptomatic patients with increased CK to muscle cramps and pain syndrome or rigid-spine syndrome. In addition clinical severity and disease progression are greatly variable. We report on a family with 3 siblings characterized by an unusual adult-onset Pompe disease including dysphagia and weakness of tongue, axial and limb-girdle muscles, in association with atypical globular inclusions in muscle fibres. Our study confirms the great clinical and histological variability of adult-onset Pompe disease and further supports the need of careful evaluation of bulbar function in patients affected by this pathology.Key words: Pompe disease, globular inclusions, bulbar symptomsGlycogen storage disease type II (Pompe disease or acid maltase deficiency) is a rare autosomal recessive muscular disorder characterized by deficiency of acidalfa glucosidase (GAA), determining accumulation of glycogen in the lysosomes, mainly in cardiac and skeletal muscle cells. Typical phenotypes of glycogenosis type II include the severe classic infantile form, characterized by severe muscle weakness and hypertrophic cardiomyopathy, almost invariably fatal by 12 months, a "non-classic" form presenting between 1 and 2 years of age and the lateonset form, presenting at any time after the age of 1 year, including juvenile and adult-onset subtypes, which are considered as part of a continuous clinical spectrum (1). In particular the adult-onset form presents with slowly progressive proximal lower limb and/or paraspinal muscle weakness, often followed by restrictive respiratory failure, which could be life-threatening, as it is in infants and children (2). However the clinical spectrum of adultonset form is wide, ranging from asymptomatic patients with increased CK to muscle cramps and pain syndrome or rigid-spine syndrome (2, 3). Furthermore clinical severity and disease progression is greatly variable.We report on a family with 3 siblings with an unusual adult-onset Pompe disease clinically characterized by weakness of bulbar, axial and limb-girdle muscles in association with atypical histopathological changes.