The spontaneous mouse mutant adrenocortical dysplasia (acd) is characterized by defects in the adrenals, kidneys, and gonads of adult mutant mice and by caudal dysgenesis and vertebral segmentation defects in acd embryos. This association of defects mirrors those identified in patients with known or suspected abnormalities in adrenocortical development, including adrenal hypoplasia congenita and IMAGe association. The identification of the Acd gene in mice has prompted the study of its human homolog ACD, which has recently been shown to be a regulator of telomere length. Sequencing of ACD in 15 patients revealed no coding mutations, but three novel SNPs were identified.