Adult polyglucosan body disease (APBD) usually presents with progressive spastic paraparesis, neurogenic bladder, and distal lower limb sensory abnormalities. It is caused by mutations in the glycogen branching enzyme gene (GBE1).We describe a woman with an unusual phenotype manifesting as progressive left brachial more than lumbosacral plexopathies, with central sensory and corticospinal tract involvement.Magnetic resonance imaging of the brain and cervical spine showed abnormal T2 signal within the ventral pons and medulla bilaterally, involving the pyramidal tracts and the medial leminisci. There was also medullary and cervical spine atrophy. On nerve biopsy, large polyglucosan bodies were noted in the endoneurium. The patient was found to be compound heterozygous for 2 novel mutations in GBE1. Peripheral blood leukocyte GBE activity was markedly reduced to 7% of normal, confirming the diagnosis of APBD.In this report we describe a new phenotype of APBD associated with 2 novel mutations. Muscle Nerve 53: 976-981, 2016.