HbF levels are hereditable and the phenomenon of raised HbF in SCA patients where the HMOX1 gene polymorphism associated with HbF levels is absent, may be due to the other SNPs linked to HbF regulation like mutations within the β-globin gene cluster which includes XmnI polymorphism (− 158 C→T) or in the γ globin promoter region33. Here, HMOX1 is linked to autosomal dominant cerebellar ataxia.