The classical features of Kallmann syndrome with anosmia and hypogonadotropic hypogonadism were observed in two sisters aged 13 and 19. They had additional malformations including anosmia, bilateral vesico-ureteral reflux and unilateral hearing loss. One of the girls had unilateral coloboma of the optic nerve. The father had unilateral hearing loss and duplication of the left ureter; he died of an unrecognized coarctation of the aorta. He had no clinical signs of hypogonadism or anosmia. It is suggested that the malformations observed in these patients may be due to a dominant inherited defect of embryonic cell migration, resulting in different phenotypic expressions within the same family, including the Kallmann syndrome.