Prevalence of MTHFR Polymorphisms in Patients With Hypermobile Ehlers‐Danlos Syndrome and Hypermobile Spectrum Disorders in a US Hypermobility Clinic

Abstract

Objective Hypermobile Ehlers‐Danlos syndrome (hEDS) and hypermobility spectrum disorders (HSD) are characterized by joint hypermobility, joint subluxations and dislocations, hyperextensible skin, and chronic and progressive multiorgan comorbidities. Diagnosing hEDS and HSD is difficult because of variable phenotypes and unknown genetic etiology. In our clinic, we observed many patients with hEDS and HSD with a high serum level of unmetabolized folate, which suggests that hypermobility may be linked to methylenetetrahydrofolate reductase (MTHFR)–mediated folate metabolism. The present study aims to examine the prevalence of MTHFR polymorphisms, C677T and A1298C, among patients with hEDS and HSD. Methods Clinical and demographic information of patients visiting our hypermobility clinic from January 2023 to July 2023 were retrospectively reviewed. Continuous variables were reported as mean ± SD and range, whereas categorical variables were reported as total count and percentage. Results Among 157 patients, 93% of patients were female patients, 52.2% were diagnosed with hEDS, and 47.8% were diagnosed with HSD. Interestingly, 85% of the patients had MTHFR C677T and/or A1298C polymorphisms in heterozygous or homozygous state. MTHFR 677CT/TT genotype was present in 52.9% of cases, and 49.7% of patients had 1298AC/CC genotype. In addition,14% of patients with hypermobility exhibited MTHFR 677TT genotype, 10.2% showed 1298CC genotype, and 17.2% displayed combined heterozygosity, collectively representing 41.4% hypermobile patients with two copies of MTHFR variant alleles. Conclusion There is a high prevalence of MTHFR polymorphisms among patients with hypermobility, which supports the hypothesis that hypermobility may be dependent on folate status.