Adult polyglucosan body disease: case description of an expanding genetic and clinical syndrome.

A non-Jewish patient is described who had adult polyglucosan body disease (APBD) and glycogen branching enzyme (GBE) deficiency without GBE mutation. A heterozygous polymorphism (Val160Ile) was found, and also discovered in 1 of 50 normal individuals. Magnetic resonance imaging demonstrated increased T2 signal in the midbrain, medullary olives, dentate nuclei, cerebellar peduncles, and internal and external capsules, with vermian atrophy. Both muscle and nerve biopsy revealed perivascular inflammatory infiltrates. These findings expand the clinical and genetic spectrum of APBD. Factors other than mutation of the expressed GBE gene may cause enzyme deficiency and varied expression and development of APBD.