Genetic refinement of the hereditary neuralgic amyotrophy (HNA) locus at chromosome 17q25

Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant, recurrent focal neuropathy. HNA is characterised by episodes of painful brachial plexus neuropathy with muscle weakness and atrophy, as well as sensory disturbances. Single episodes are commonly preceded by non-specific infections, immunisations or parturition. Mild dysmorphic features and short stature are present in some HNA families, but absolute co-segregation with HNA has not been described. To refine the previously described HNA locus on chromosome 17q25, we performed a genetic linkage study in five HNA families with different geographic origins. Significant linkage was obtained with chromosome 17q24–q25 short tandem repeat (STR) markers in three HNA families and suggestive linkage was found in the other two HNA families. Analysis of the informative recombinations in affected individuals allowed us to reduce the HNA linkage interval to a candidate region of 3.5 cM.