Harboyan Syndrome

Clinical Characteristics
Ocular Features: 

The combination of congenital endothelial dystrophy and progressive neural deafness is known as Harboyan syndrome.  This disorder must be distinguished from another autosomal recessive disorder, congenital endothelial dystrophy 2 or CHED2 (217700), in which deafness does not occur.  While the corneal disease in Harboyan is present at birth, the deafness often does not become obvious until the second and third decades of life although audiometry can detect some hearing loss in the first decade.  The cornea is thickened and edematous resulting in various degrees of visual impairment, even to the level of counting fingers.  Electrophysiologic studies have been normal.

Systemic Features: 

No systemic abnormalities have been reported.

Genetics

This is an autosomal recessive disorder caused by a mutation in the SLC4A11 gene located on chromosome 20 (20p13-12).  It is allelic to simple, congenital endothelial corneal dystrophy (CHED2) (217700).  About half of reported cases occur sporadically and the rest have been reported in offspring of consanguineous matings.  Less than 30 cases have been reported worldwide.

Treatment
Treatment Options: 

Corneal transplantation is the treatment of choice and can result in substantial visual improvement.

References
Article Title: 

Congenital hereditary endothelial dystrophy with

Desir J, Abramowicz M. Congenital hereditary endothelial dystrophy with
progressive sensorineural deafness (Harboyan syndrome). Orphanet J Rare Dis. 2008 Oct 15;3:28. Review.

PubMed ID: 
18922146

Congenital corneal dystrophy

Harboyan G, Mamo J, Kaloustian V der, Karam F. Congenital corneal dystrophy.
Progressive sensorineural deafness in a family. Arch Ophthalmol. 1971 Jan; 85(1):27-32.

PubMed ID: 
5312820

References

Desir J, Abramowicz M. Congenital hereditary endothelial dystrophy with
progressive sensorineural deafness (Harboyan syndrome). Orphanet J Rare Dis. 2008 Oct 15;3:28. Review.

PubMedID: 18922146

Desir J, Moya G, Reish O, Van Regemorter N, Deconinck H, David KL, Meire FM,
Abramowicz MJ. Borate transporter SLC4A11 mutations cause both Harboyan syndrome and non-syndromic corneal endothelial dystrophy. J Med Genet. 2007 May;44(5):322-6.

PubMedID: 17220209

Harboyan G, Mamo J, Kaloustian V der, Karam F. Congenital corneal dystrophy.
Progressive sensorineural deafness in a family. Arch Ophthalmol. 1971 Jan; 85(1):27-32.

PubMedID: 5312820