Choroidal Dystrophy, Central Areolar 1

Clinical Characteristics
Ocular Features: 

The primary feature of this form of macular dystrophy is atrophy of the RPE and choriocapillaris centralized to the macula.  In early stages among young patients in the second decade of life, some pigment changes are seen in the parafoveal area.  Later, the central macula develops hypopigmentation followed by atrophy of the choriocapillaris.  The area is usually sharply defined but fluorescein angiography often shows multiple window defects beyond the edges.  The same region often has speckled autofluorescence.  Secondary dysfunction of the photoreceptors in this area leads to some mild degree of vision loss in adults between the ages of 30 and 60 years but this progressive disease may eventually result in legal blindness.  The ERG demonstrates a cone dystrophy. The rate of disease progression is highly variable.  Visual acuity varies considerably as does the appearance of the macula.  Older individuals may be misdiagnosed as having age-related macular degeneration. 

Systemic Features: 

There is no associated systemic disease. 

Genetics

CACD1 is caused by a hterozygous mutations in GUCY2D gene localized to 17p13.  One large three generation Irish family has been reported.

For a somewhat similar disorder see choroidal dystrophy, central areolar 2 (613105).

CACD is a genetically heterogeneous disorder with mutations in several genes responsible.  The majority of patients have one of several mutations in the PRPH2 gene (6p21.1-cen) and the inheritance pattern seems to be autosomal recessive (CACD2).  However, other family trees in which mutations in PRPH2 were excluded suggest autosomal dominant inheritance (CACD3; 613144) suggesting genetic heterogeneity such as the CACD1 condition described here.   

 

Treatment
Treatment Options: 

There is no treatment of the macular disease.  However, some patients can benefit from low vision aids. 

References
Article Title: 

Central areolar choroidal dystrophy

Boon CJ, Klevering BJ, Cremers FP, Zonneveld-Vrieling MN, Theelen T, Den Hollander AI, Hoyng CB. Central areolar choroidal dystrophy. Ophthalmology. 2009 Apr;116(4):771-82, 782.e1.

PubMed ID: 
19243827

References

Hughes AE, Meng W, Lotery AJ, Bradley DT. A novel GUCY2D mutation, V933A, causes central areolar choroidal dystrophy. Invest Ophthalmol Vis Sci. 2012 Jul 12;53(8):4748-53.

PubMedID: 22695961

Ouechtati F, Belhadj Tahar O, Mhenni A, Chakroun S, Chouchene I, Oueslati S, Rebai A, Abdelhak S, Jeddi-Blouza A. Central areolar choroidal dystrophy associated with inherited drusen in a multigeneration Tunisian family: exclusion of the PRPH2 gene and the 17p13 locus. J Hum Genet. 2009 Oct;54(10):589-94.

PubMedID: 19696794

Boon CJ, Klevering BJ, Cremers FP, Zonneveld-Vrieling MN, Theelen T, Den Hollander AI, Hoyng CB. Central areolar choroidal dystrophy. Ophthalmology. 2009 Apr;116(4):771-82, 782.e1.

PubMedID: 19243827