Analysis of clinical and electrophysiological charactertics of hereditary neuropathy with liability to pressure palsies

Objective To summarize and analyze the clinical and electrophysiological characteristics of hereditary neuropathy with liability to pressure palsies (HNPP). Methods and Results Three patients with HNPP confirmed by gene test who were admitted to Beijing Hospital from January 2014 to December 2020 were retrospectively analyzed. All 3 patients were male. Age of onset/diagnosis (duration ending up to December 2020) were 13/25, 57/57 and 20/71 years old, respectively. All of them had heterozygous deletion mutation of the PMP22 gene. All 3 patients initially presented with common peroneal nerve palsy and were able to achieve complete recovery at the early stage. Electrophysiological changes were characterized by conduction block at entrapment sites, reduction in both sensory and motor conduction velocity, and decreased amplitude of sensory nerve action potentials, prolonged distal latency, which were affected more widely than clinically involved. At the late stage, the symptoms might not fully recover after the attack. Conclusions At the early stage of HNPP, the electrophysiological abnormalities exceed the range that was clinically involved. This feature might be helpful for early diagnosis. Detection of peripheral nerve conduction blocks at entrapment sites can assist in differential diagnosis with Guillan‑ Barré syndrome (GBS), multifocal motor neuropathy (MMN), multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) and Charcot‑Marie‑Tooth disease type 1A (CMT1A)