The human germ cell-less (HGCL): A candidate gene for Alström syndrome

Alström syndrome (ALMS1, MIM 203800) is a rare autosomal recessive disorder characterized by retinitis pigmentosa, deafness, obesity, hyperlipidemia and non-insulin dependent diabetes mellitus (NIDDM). In some cases, acanthosis nigricans, cardiomyopathy, hepatic dysfunction, progressive chronic nephropathy and male hypogonadism are also observed. Linkage analysis studies mapped Alström syndrome to chromosome 2p13. Several genes in this region, including TGFA and DCTN1, have been analyzed and excluded as candidate genes for this disease. Here we report the cloning and characterization of HGCL, the human homologue of the germ cell-less gene of Drosophila and mouse, which maps to the chromosomal region identified for Alström syndrome. Three highly conserved gcl proteins which have been identified contain a BTB/POZ domain, present in a variety of regulatory proteins, many of which have DNA-related functions, such as repression of transcription. Mouse gcl has been suggested to repress the transcriptional activity of the E2F-DP complex and to negatively regulate the cell cycle. Based on the chromosomal mapping of HGCL, and its pattern of expression in various human tissues, we propose HGCL to be a candidate gene for Alström syndrome.