One example is the rs13121031 SNP located within the alternative promoter of the cerebellar ataxia-associated gene TRPC3. The C allele of this SNP has decreased methylation of surrounding CpG sites relative to the G allele in several tissues and this correlates with increased expression of the C allele relative to the G allele in brain Martin-Trujillo et al. 2011). Here, TRPC3 is linked to cerebellar ataxia.