The present invention relates generally to the field of human genetics. Specifically, the present invention relates to methods and materials used to detect a human sporadic DCM predisposing gene, specifically the dystrophin gene, some mutant alleles of which cause susceptibility to sporadic DCM. More specifically, the invention relates to germline mutations in the dystrophin gene and their use in the diagnosis of predisposition to sporadic DCM. The invention also relates to the prophylaxis and/or therapy of sporadic DCM associated with a mutation in the dystrophin gene. The invention further relates to the screening of drugs for sporadic DCM therapy. Finally, the invention relates to the screening of the dystrophin gene for mutations/alterations, which are useful for diagnosing the predisposition to sporadic DCM.