There is a general consensus to offer clinical screening for heart disease to relatives of younger DCM patients to be able to detect the disease before symptoms arise and if necessary commence early treatment and thus avoid serious disease complications and improve the prognosis. In families where the clinical examinations did not reveal any other relatives with signs of the disease, it is unclear if there is any benefit in continued controls of the apparently healthy relatives to reveal a possible later debut of the disease. The hope is that genetic investigations can assist in clarifying this question. If it is possible to identify a disease related genetic mutation in the index patient with DCM, it would be possible to offer genetic diagnostics to relatives and hereby identify mutation carriers in risk of developing the disease and offer these relatives relevant clinical controls and disease monitoring, while relatives without the mutation can be discharged without any further investigations.