Progress in the molecular understanding of hereditary peripheral neuropathies reveals new insights into the biology of the peripheral nervous system.

Since the first description of the autosomal dominant inherited peripheral neuropathy Charcot-Marie-Tooth (CMT) disease over a century ago, there has been considerable disagreement, based on morphological abnormalities of both the axons of peripheral nerves and their surrounding Schwann cells, as to whether this disorder is due primarily to an autonomous Schwann cell defect or an autonomous neuronal defect. Recently, the Schwann cell protein peripheral myelin protein 22 (PMP-22) has been implicated in the molecular pathogenesis of hereditary peripheral neuropathies in mice and humans. Reinterpretations of morphological studies of the diseased nerves in light of these findings strongly suggest that Schwann cells have a much more pronounced influence on their ensheathed axons than previously anticipated.