The invention provides isolated nucleic acids molecules, designated DHDR-7 nucleic acid molecules, which encode novel human dehydrogenase molecules. The invention also provides antisense nucleic acid molecules, recombinant expression vectors containing DHDR-7 nucleic acid molecules, host cells into which the expression vectors have been introduced, and nonhuman transgenic animals in which a DHDR-7 gene has been introduced or disrupted. The invention still further provides isolated DHDR-7 polypeptides, fusion polypeptides, antigenic peptides and anti-DHDR-7 antibodies. Diagnostic methods utilizing compositions of the invention are also provided.