The present invention relates to an in vitro method for diagnosing and/or predicting hereditary cerebellar ataxia in a dog, and/or identifying a dog which is healthy carrier of hereditary cerebellar ataxia, comprising determining the presence or absence of an homozygous or heterozygous genetic variation in the arylsulfatase G gene sequence in a biological sample from said dog, as compared with the arylsulfatase G gene sequence of a healthy non-carrier dog, wherein the presence of said homozygous genetic variation indicates that said dog is or will be affected by hereditary cerebellar ataxia, and the presence of said heterozygous genetic variation indicates that said dog is healthy carrier of hereditary cerebellar ataxia, said dog being of a breed selected in the group consisting of American Staffordshire Terrier, American Pit Bull Terrier and Pit Bull type.