Aniridia is a rare genetic eye disorder with a poorly formed iris leading to vision loss and nystagmus presenting in early infancy. Other eye abnormalities, often of later onset, include cataract, glaucoma, and corneal opacification and vascularization. Aniridia is passed on in an autosommal domminant patter, but may occur as an isolated ocular abnormality without systemic involvement, caused by mutation of the PAX6 gene.
Kallmann syndrome consists of congenital, isolated, idiopathic hypogonadotropic hypogonadism (small genitals) and anosmia (no sense of smell). The gene responsible for the X-linked form of Kallmann syndrome, KAL1, encodes a protein, anosmin, that plays a key role in the migration of GnRH neurons and olfactory nerves to the hypothalamus. It can also be inherited in dominant and recessive forms.