Respiratory Muscle Dysfunction in Hereditary Motor and Sensory Neuropathy

lb the Editor.—We wish to congratulate Eichacker et al¹ who, in the August issue of the Archives, presented an interesting clinical study on a selected cohort of patients with hereditary motor and sensory neuropathy (HMSN), type I. We are in full agreement with the authors that respiratory muscle dysfunction should be considered as part of the spectrum of neuromuscular involvement in HMSN. We also wish to point out that this association was previously described by Chan et al² in April 1987. Detailed clinical, basic pulmonary physiologic, and advanced pulmonary physiologic documentation demonstrating phrenic-diaphragmatic impairment in two patients with HMSN, type I, were presented in that study. Subsequent to this description, Dyer and Callahan³ reported another patient in January 1987, and Laroche et al⁴ provided further evidence on two more patients in June 1988.

The statement by Eichacker et al that "respiratory muscle deficit does not