Akhenaten was one of Egypt's most controversial pharaohs, in part because of his strange appearance in images produced after he had declared Aten, the Sun-disc, his one-and-only god. Whether these were symbolic representations or realistic ones that indicate a deforming genetic disorder is the subject of continuing debate. The authors present evidence that the bizarre physical features portrayed in these images are not only realistic but were shared by many members of Egypt's 18th Dynasty. The features are best explained by either 2 different familial disorders-the aromatase excess syndrome and the sagittal craniosynostosis syndrome-or a variant of the Antley-Bixler syndrome caused by a novel mutation in one of the genes controlling the P450 enzymes, which regulate steroidogenesis and cranial bone formation.