[Diagnosis of neurometabolic and neurodegenerative diseases by cutaneous biopsy]

Cutaneous biopsy is of great use in the diagnosis of neurodegenerative diseases, especially neurometabolic and inborn errors of metabolism. The sweat glands, especially the eccrine ones, and certain cellular elements in the adventitial dermis like the Schwann cells, axons, endothelium and fibroblasts, are altered in inborn errors of metabolism and in certain neurodegenerative diseases. The morphology and placement of these deposits, as for example axonal spheroids, Lafora bodies, homogeneous cytoplasmic bodies and prismatic bodies, permit to diagnosis the disease. Differential diagnosis must be made with simulating storage disorders. The study of skin biopsy must be complete and rigorous and follow a system of work, that includes electron microscopy, enzymatic determination and, occasionally, molecular biology. Valuable information about neurodegenerative diseases as muscular dystrophies, axonal neuropathy, Alzheimer disease and others can be carried out by skin biopsy. It can be foreseen that in the future indications of skin biopsy will be extended to other neurodegenerative diseases.