A new variant of type IV glycogenosis with primary cardiac manifestation and complete branching enzyme deficiency

Type IV glycogenosis (polyglucosan body disease) is a rare congenital autosomal recessive inherited disorder, caused by lack of the branching enzyme (amylo-1,4-1,6 transglucosidase). This deficiency leads to storage of abnormal glycogen (polyglucosan bodies) in the liver and other tissues. The clinical onset of the disease is insidious with non-specific gastrointestinal symptoms followed by progressive hepatic failure. Usually patients die due to hepatic cirrhosis within 4 years. Sometimes myopathy of the heart and skeletal muscle is also present. In these cases, the clinical onset is often later than in typical cases. We report on two brothers with primarily cardiac manifestation and late onset of the disease. The older one started to suffer from progressive dilated cardiomyopathy at the age of 18 years, presenting with severe heart failure, hepatosplenomegaly, ascites and peripheral oedema. He also demonstrated myopathy and muscular atrophy especially of the shoulder and lower limbs. Initially he improved on medical therapy, but one year later severe heart failure recurred followed shortly afterwards by sudden cardiac death. Right heart and skeletal muscle biopsies were performed while he was alive. These, as well as the autopsy, revealed massive accumulation of polyglucosan bodies. In both heart and skeletal muscle, complete branching enzyme deficiency could be proven. His 14-year-old brother showed similar clinical findings of mild dilated cardiomyopathy. His muscle biopsy also revealed polyglucosan body myopathy. Thus, in young patients presenting with congestive cardiomyopathy, type IV glycogenosis has to be considered in the differential diagnosis.