Epidemiological Study of Pediatric Neuromuscular Disorders in South West France Regions

Aim: Very limited epidemiological data on neuromuscular disorders pediatric population exist around the world. In France, such pediatric epidemiological study is seriously lacking. We investigated the pediatric prevalence (under 18) and we described the epidemiological profile of neuromuscular disorders on Southwest regions of France, from May 1, 2001 to June 1, 2022. We screened medical and genetic hospital records in three expert centers (Toulouse, Montpellier and Bordeaux) for neuromuscular disorders. Methods: We performed a retrospective cohort study with data extracted from the French National Rare Disease Databank that gathers a minimal dataset on all patients followed-up in French rare disease expert center in France. We then estimated: (1) Prevalence by diagnosis and age group or by year with Poisson confidence interval (2) survival from birth analyses using Kaplan-Meier for muscular disorders sub-cohort analysis. Results: Over the period, 1,621 children were included with 62% of males. We estimate the regional prevalence at 37.9 (IC95% = 35.3 - 40.7) for 100,000 inhabitants under 18 years old. For muscular disorders sub-cohort analysis, we estimate regional prevalence for Duchene, Becker, Charcot-Marie-Tooth type 1 and Spinal muscular atrophy at 5 (IC95% = 4.1 - 6.1), 1.3 (IC95% = 0.9 - 1.9), 6.2 (IC95 = 5.1 - 7.3) and 3.2 (IC95% = 2.5 - 4.1) respectively. Conclusion: Our findings seem in accordance with previous but scarce other data. Together, all may reflect a consensus among different countries supporting a global neuromuscular disorders’ pediatric prevalence about 38/100000 may, about 5 for Duchene, 1.5 for Becker, 6.2 for Charcot-Marie-Tooth type 1, 3.2 for Spinal muscular atrophy. This is the first time that it’s possible to estimate with robustness French pediatric epidemiological prevalence of neuromuscular disorders, that constitute a strength starting point to be confirmed by the extend of analyze to all French expert centers.