The Xmn1 polymorphism (HBG2 rs7482144, i.e., Senegal haplotype) was protective against an ACR ≥ 30 mg/g in adults and children with homozygous SCA (OR 0.22, p = 0.035) but not against proteinuria >200 mg/g creatinine [41]. Here, HBG2 is linked to autosomal dominant cerebellar ataxia.