Yield of next-generation neuropathy gene panels in axonal neuropathies

The use and utility of targeted gene panels for diagnosing the type of Charcot-Marie-Tooth have grown rapidly because commercial gene panels that contain most of the relevant genes are available and affordable for many patients. We used a targeted gene panel to analyze 175 patients who had an unexplained axonal polyneuropathy affecting large myelinated axons, 86 of whom reported a family history of neuropathy, and 89 of whom did not. In patients reporting a family history, the panel identified a pathogenic variant causing the neuropathy in six cases (7%); in patients not reporting a family history, the gene panel identified pathogenic variants causing neuropathy in two patients (2%). Interpretation in a tertiary referral setting, current gene panels identify the genetic cause of neuropathy in a small minority of patients who have an unexplained axonal neuropathy, even in those reporting a family history.