Elderly patients with suspected Charcot-Marie-Tooth disease should be tested for the TTR gene for effective treatments

Background and aims: Some hereditary transthyretin (ATTRv) amyloidosis patients are misdiagnosed as Charcot−Marie−Tooth disease (CMT) at onset. We assess the findings to identify ATTRv amyloidosis among patients with suspected CMT to screen transthyretin gene variants for treatments. Methods: We assessed clinical, cerebrospinal fluid, and electrophysiological findings by comparing ATTRv amyloidosis patients with suspected CMT (n = 10) and CMT patients (n = 489). Results: The median (interquartile range) age at onset of neurological symptoms was 69 (64.2–70) years in the ATTRv amyloidosis vs 12 (5–37.2) years in CMT group (Mann−Whitney U, p < 0.01). The proportion of patients with initial sensory symptoms was 70% in the ATTRv amyloidosis group vs 7.1% in CMT group (Fisher’s exact, p < 0.01). The proportion of patients with histories of suspected chronic inflammatory demyelinating polyneuropathy (CIDP) were 50% in the ATTRv amyloidosis group vs 8.7% in CMT group (Fisher’s exact, p <.01). Other measures and outcomes were not different between the two groups. Five of the six patients with ATTRv amyloidosis received treatment and survived. Interpretation: For effective treatments, the transthyretin gene should be screened in patients with suspected CMT with old age at onset of neurological symptoms, initial sensory symptoms, and histories of suspected CIDP.