Peripheral nervous system manifestations of Chediak-Higashi disease.

INTRODUCTION: Chediak-Higashi disease (CHD) is a rare autosomal recessive disorder with hematologic, infectious, pigmentary, and neurologic manifestations. Classic CHD (C-CHD) presents in early childhood with severe infectious or hematologic complications unless treated with bone marrow transplantation. Atypical CHD (A-CHD) has less severe hematologic and infectious manifestations. Both C-CHD and A-CHD develop neurological problems. METHODS: Eighteen patients with CHD (9 A-CHD and 9 C-CHD) underwent electrodiagnostic studies as part of a natural history study (NCT 00005917). Longitudinal studies were available for 10 patients. RESULTS: All A-CHD patients had either sensory neuropathy, sensorimotor neuropathy, and/or diffuse neurogenic findings. In C-CHD, 3 adults had sensorimotor neuropathies with diffuse neurogenic findings, and 1 adult had a sensory neuropathy. The 5 children with C-CHD had normal electrodiagnostic findings. CONCLUSIONS: CHD can result in sensory or sensorimotor neuropathies and/or a diffuse motor neuronopathy. It may take 2-3 decades for the neuropathic findings to develop, because children appear to be spared. Muscle Nerve 55: 359-365, 2017.

Electrical impedance myography discriminates congenital muscular dystrophy from controls.

INTRODUCTION: Electrical impedance myography (EIM) is an emerging non-invasive, highly reproducible electrophysiological technique that objectively characterizes muscle structure and composition by measuring bioimpedance. We assessed the ability of EIM ability to discriminate 2 forms of congenital muscular dystrophy (CMD), laminin α2 (LAMA2)-deficient CMD and collagen VI-deficient (COL6) CMD, from a group of healthy children. We also investigated correlations between subcutaneous fat thickness and EIM parameters. METHODS: Twenty-eight children with LAMA2 CMD (n = 12) or COL6 (n = 16) CMD and 18 normal children underwent EIM testing. RESULTS: The EIM 50-kHz phase was decreased in LAMA2 and COL6 CMD when compared with controls (P < 0.001). Reactance, however, was decreased in COL6 but not LAMA2 CMD compared with controls (P < 0.001). CONCLUSIONS: Our findings suggest that EIM may be useful in discriminating CMD from controls and may serve as a useful biomarker to follow disease progression in clinical trials.