NEURAL REGULATION OF ACID MALTASE IN AN UNUSUAL ADULT-ONSET DEFICIENCY

In a 48-year-old female, the first symptoms apparently manifested them selves 18 years before, with occasional tripping and weakness in both legs. During the next 18 years, weakness progressed and the patient de veloped a waddling gait; she became unable to rise from a lying or sea ted position unassisted and the shoulder girdle also became affected. Neurological examination revealed limb and shoulder girdle predominant ly involving the lower extremities. We established cell cultures from muscle biopsy specimens obtained from our patient and carried out morp hological analysis which, although aspecific, demonstrated clear signs of neurogenic suffering. This was confirmed in EMG studies performed. Biochemical analysis revealed very low acid maltase residual activity . We describe an unusual case of adult-onset acid maltase deficiency ( AMD) with neurogenic atrophy and low residual activity. Innervated myo fibres prepared by co-culturing the patient's myoblasts, with spinal c ord foetal mouse explants were not associated with an abnormal in vitr o maturation of the innervated myofibres as expected by the very low r esidual enzymatic activity found both in the muscle biopsy specimens a nd in the muscle cultures. There is strong suggestion that factors oth er than the amount of residual activity must be involved to determine the clinical manifestation of this disease.