The close association between HPRT-CCM and CDKN1B Ct values as well as the equally significant differential expression of genes related to both HPRT-CCM and CDKN1B in EMBs from DCM versus DCMi patients infer a possible relevance of CDKN1B as a housekeeping gene. The gene discussed is CDKN1B; the disease is familial dilated cardiomyopathy.