Prevalence of Charcot-Marie-Tooth disease across the lifespan: a population-based epidemiological study

Objectives: This population-based study aimed to determine age-standardised prevalence of Charcot-Marie-Tooth disease (CMT) across the lifespan using multiple case ascertainment sources.

Design: Point-prevalence epidemiological study in the Auckland Region of New Zealand (NZ).

Setting: Multiple case ascertainment sources including primary care centres, hospital services, neuromuscular disease registry, community-based organisations and self-referral were used to identify potentially eligible participants.

Participants: Adults (≥16 years, n=207, 87.7%) and children (<16 years, n=29, 12.3%) with a confirmed clinical or molecular diagnosis of CMT, hereditary sensory neuropathy, hereditary motor neuropathy or hereditary neuropathy with liability to pressure palsies who resided in the Auckland Region of NZ on 1 June 2016.

Primary outcome: Prevalence per 100 000 persons with 95% CIs by subtype, age and sex were calculated and standardised to the world population.

Results: Age-standardised point prevalence of all CMT cases was 15.7 per 100 000 (95% CI 11.6 to 21.0). Highest prevalence was identified in those aged 50-64 years 25.2 per 100 000 (95% CI 19.4 to 32.6). Males had a higher prevalence (16.6 per 100 000, 95% CI 10.9 to 25.2) than females (14.6 per 100 000, 95% CI 9.6 to 22.4). Prevalence of CMT1A was 6.9 per 100 000 (95% CI 5.6 to 8.4). The majority (93.2%) of cases were identified through medical records, with 6.8% of cases uniquely identified through community sources.

Conclusions: A small but significant proportion of people with CMT are not connected to healthcare services. Epidemiological studies using medical records alone to identify cases may risk underestimating prevalence. Further studies using population-based methods and reporting age-standardised prevalence are needed to improve global understanding of the epidemiology of CMT.