Brain-derived neurotrophic factor and risk for primary adult-onset cranial-cervical dystonia

Background and purpose: Adult‐onset dystonia may be related, amongst other factors, to abnormal neuronal plasticity in cortical and subcortical structures. Brain‐derived neurotrophic factor is a major modulator of synaptic efficiency and neuronal plasticity. Recent works documented that a single nucleotide polymorphism (SNP) of the BDNF gene, the Val66Met SNP, modulates short‐term plastic changes within motor cortical circuits. In this study we aimed at exploring the effect of this SNP upon the risk of developing common forms of primary adult‐onset dystonia. Methods: We explored the influence of the Val66Met SNP of the BDNF gene on the risk of cranial and cervical dystonia in a cohort of 156 Italian patients and 170 age‐ and gender‐matched healthy control subjects drawn from the same population. Results: The presence of the rare Met allele was not significantly associated with the diagnosis of dystonia (age‐ and gender‐adjusted odds ratios of 1.22, P = 0.38). The study had a >90% power to detect a 50% change in the risk of developing cranial‐cervical dystonia associated with the presence of the Met allele. Moreover, there was no relationship between Val66Met SNP and age at dystonia onset or type of dystonia. Conclusion: Our data do not support the common variant Val66Met of the BDNF gene as an etiologic factor shared by the various forms of primary adult‐onset dystonia.