[Hereditary neural amyotrophy (HNA): clinical and molecular genetic basis].

Hereditary neuralgic amyotrophy (HNA) and hereditary neuropathy with liability to pressure palsies (HNPP) are hereditary focal neuropathies. In this study we describe three families suffering from HNA. These families were examined clinically and electrophysiologically. Linkage analysis with markers from distal chromosome 17 was performed in a three-generation family. HNA could be separated from HNPP in all three families based on clinical and electrophysiological findings. HNA was characterised by recurrent episodes of painful brachial plexus lesions. In contrast to HNPP, no evidence for generalised neuropathy was found in the HNA families. Linkage analysis confirmed the HNA locus on distal chromosome 17. Additionally, we were able to refine the HNA locus to a 16 cM region on chromosome 17q24-q25.