# Repeated clear benefits of immunotherapy in a patient with Charcot-Marie-Tooth disease carrying a rare point mutation in PMP22

## TL;DR

A patient with a rare PMP22 mutation showed repeated benefits from immunotherapy, highlighting the need for thorough genetic testing in similar cases.

## Contribution

Highlights the importance of genetic testing for PMP22 point mutations in patients with suspected CIDP.

## Key findings

- A patient with a rare PMP22 mutation (c.320G > A, p.G107D) showed clear responses to immunotherapy for 13 years.
- The patient was eventually diagnosed with CMT, not CIDP, emphasizing the need for comprehensive genetic testing.

## Abstract

We describe a unique patient who had been diagnosed with inflammatory demyelinating polyneuropathy (CIDP) for 13 years with frequent clear responses to immunotherapies and was finally diagnosed with Charcot-Marie-Tooth disease (CMT) with a rare point mutation in PMP22 (c.320G > A, p.G107D). Some patients diagnosed with young-onset CIDP may have underlying CMT, and extensive genetic testing including point mutations of PMP22 gene is required not to miss the diagnosis.