Defects in PAX6 are the cause of aniridia (AN) [MIM:106210]. A congenital, bilateral, panocular
disorder characterized by complete absence of the iris or extreme iris hypoplasia. Aniridia is not
just an isolated defect in iris development but it is associated with macular and optic nerve
hypoplasia, cataract, corneal changes, nystagmus. Visual acuity is generally low but is unrelated
to the degree of iris hypoplasia. Glaucoma is a secondary problem causing additional visual loss over time.
Defects in PAX6 are a cause of Peters anomaly (PAN) [MIM:604229]. Peters anomaly consists of a
central corneal leukoma, absence of the posterior corneal stroma and Descemet membrane, and a
variable degree of iris and lenticular attachments to the central aspect of the posterior cornea.
Defects in PAX6 are a cause of foveal hypoplasia (FOVHYP) [MIM:136520]. Foveal hypoplasia can
be isolated or associated with presenile cataract. Inheritance is autosomal dominant.
Defects in PAX6 are a cause of keratitis hereditary (KERH) [MIM:148190]. An ocular disorder
characterized by corneal opacification, recurrent stromal keratitis and vascularization.
Defects in PAX6 are a cause of coloboma ocular (COLO) [MIM:120200]; also known as uveoretinal
coloboma or coloboma of iris, choroid and retina. Ocular colobomas are a set of malformations
resulting from abnormal morphogenesis of the optic cup and stalk, and the fusion of the fetal
fissure (optic fissure). Severe colobomatous malformations may cause as much as 10% of the childhood
blindness. The clinical presentation of ocular coloboma is variable. Some individuals may present
with minimal defects in the anterior iris leaf without other ocular defects. More complex
malformations create a combination of iris, uveoretinal and/or optic nerve defects without or
with microphthalmia or even anophthalmia.
Defects in PAX6 are a cause of coloboma of optic nerve (COLON) [MIM:120430].
Defects in PAX6 are a cause of bilateral optic nerve hypoplasia (BONH) [MIM:165550]; also known
as bilateral optic nerve aplasia. A congenital anomaly in which the optic disc appears abnormally
small. It may be an isolated finding or part of a spectrum of anatomic and functional abnormalities
that includes partial or complete agenesis of the septum pellucidum, other midline brain defects,
cerebral anomalies, pituitary dysfunction, and structural abnormalities of the pituitary.
Defects in PAX6 are a cause of aniridia cerebellar ataxia and mental deficiency (ACAMD)
[MIM:206700]; also known as Gillespie syndrome. A rare condition consisting of partial rudimentary
iris, cerebellar impairment of the ability to perform coordinated voluntary movements, and
mental retardation.
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