TNFRSF1A and MEFV mutations in childhood onset multiple sclerosis

To investigate frequency and phenotype of TNFRSF1A and MEFV mutations in childhood-onset multiple sclerosis (MS). Twenty-nine clinically well characterized patients were investigated for mutations in exons 2, 3, 4, and 6 of the TNFRSF1A gene and in exons 2, 3, 9, 10 of the MEFV gene. Standardized morbidity ratio (SMR) was used to assess whether the number of observed mutations was higher than expected. Eleven out of 29 patients tested positive for mutations. Heterozygosity for the TNFRSF1A R92Q (rs4149584) variant was found in 6/11 mutation-positive patients. The SMR for R92Q in our pediatric MS population was 4.6 (95% CI 1.7-10.0), 7.0 (95% CI 2.6-15.2), and 13.6 (95% CI 5.0-29.7), depending on reference population. Six patients carried at least one heterozygous MEFV mutation with SMRs of 21.4 (95% CI 7.9-46.6) and 14.6 (95% CI 5.4-31.9). Clinical characteristics of childhood MS patients with or without mutations did not differ significantly. Conclusion One third of our childhood MS patients had a heterozygous mutation in the TNFRSF1A and/or MEFV gene. This proportion by far exceeds the number of mutations expected and was higher than in adult MS patients, suggesting that these mutations might contribute to the pathogenesis of childhood MS.