AIED

Aland Island Eye Disease

Clinical Characteristics
Ocular Features: 

This is an X-linked disorder in which males have a variety of ocular defects.  The fundus is hypopigmented and the fovea is incompletely developed.  The hypopigmentation is most pronounced in the posterior pole and peripapillary region.  Variable degrees of iris transillumination have also been noted.  Progressive axial myopia, nystagmus, astigmatism, defective night vision, and a protan color vision defect are additional cardinal features.  Females may be mildly affected with subtle nystagmus and color vision defects.  It is sometimes mislabeled as X-linked albinism (OA1, #300500) but differs importantly from that disorder by the lack of misrouting of optic nerve axons.  The eponymic label 'Forsius-Eriksson type ocular albinism' further adds to the confusion with ocular albinism. 

Systemic Features: 

No systemic abnormalities have been reported.

Genetics

This is an X-linked disorder resulting from a mutation in the CACNA1F gene located at Xp11.23.  Molecular DNA studies suggest that there may be some heterogeneity in the causative mutations but in the original family reported by Forsius and Eriksson, a 425-bp deletion in the CACNA1F gene has been found to segregate as expected in the phenotypes.  The highly variable and subtle nature of clinical manifestations in females limits their usefulness in determination of carrier status and genotyping is necessary.

The CSNB2A type of congenital stationary night blindness (300071) is caused by mutations in the same gene suggesting allelism of the two disorders.  Aland Island eye disease shares some clinical features such as night blindness and occasionally mild color vision defects but differs in the presence of progressive myopia and an abnormal fovea. 

CORDX3 (300476), a cone-rod dystrophy, is also allelic.

Pedigree: 
X-linked recessive, carrier mother
X-linked recessive, father affected
Treatment
Treatment Options: 

No treatment is available except for correction of the myopia.

References
Article Title: 

A novel CACNA1F gene mutation causes Aland Island eye disease

Jalkanen R, Bech-Hansen NT, Tobias R, Sankila EM, M?SSntyj?SSrvi M, Forsius H, de la Chapelle A, Alitalo T. A novel CACNA1F gene mutation causes Aland Island eye disease. Invest Ophthalmol Vis Sci. 2007 Jun;48(6):2498-502. PubMed PMID:17525176.

PubMed ID: 
17525176
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