Hereditary neuralgic amyotrophy and hereditary neuropathy with liability to pressure palsies: two distinct clinical, electrophysiologic, and genetic entities.

Hereditary neuralgic amyotrophy (HNA) is an autosomal disease characterized by painful episodes of brachial palsy. The presence of tomacula in some patients suggested that HNA might be genetically related to hereditary neuropathy with liability to pressure palsies (HNPP), caused by point mutations in the PMP22 gene or deletion of the region containing this gene. In a clinical, electrophysiologic, and molecular study of two families with HNA, we show that the PMP22 gene is not deleted, duplicated, or mutated in HNA and that the disease is not linked to any other gene in the HNPP deleted region. We conclude that HNA and HNPP are distinct genetic entities.