The N-myc downstream regulated gene (NDRG) family is comprised of four members, NDRG1 (also designated Drg1, RTP, rit42, Cap43 and Ndr1), NDRG2, NDRG3 and NDRG4, which share 57-65% homology. The gene encoding NDRG3 maps to human chromosome 20q11 and is predominantly expressed in testis, prostate and ovary, which suggests it may play a role in spermatogenesis.