Corneal Dystrophy And Perceptive Deafness

A number sign (#) is used with this entry because of evidence that corneal dystrophy and perceptive deafness (CDPD) is caused by homozygous or compound heterozygous mutation in the SLC4A11 gene (610206), which encodes a sodium borate cotransporter, on chromosome 20p13.

Autosomal recessive corneal dystrophy without deafness (CHED; 217700) is also caused by mutation in the SLC4A11 gene, indicating that CDPD and CHED are allelic disorders.

Clinical Features

Harboyan et al. (1971) described 3 sibs from a consanguineous mating with late-onset sensorineural deafness and corneal clouding similar to that of congenital hereditary corneal endothelial dystrophy (217700). Whereas corneal opacities were present at birth, hearing loss began during the second to third decades of life. A fourth patient, a 12-year-old boy who was the product of a different first-cousin marriage by the same father, also had this syndrome. Autosomal recessive inheritance was suggested. Nemoto (1986) reported sibs with the same clinical findings. Puga et al. (1998) reported congenital corneal dystrophy and sensorineural deafness in a 14-year-old white Brazilian girl, the offspring of a nonconsanguineous couple of Portuguese ancestry.

Magli et al. (1997) reported corneal dystrophy and sensorineural deafness in a brother and sister with nonconsanguineous parents. The affected sibs were physically and mentally normal and had 6 healthy sibs. The 35-year-old sister had a negative history of photophobia and ocular hyperemia, and there had been no intake of ototoxic drugs and no acoustic trauma. Visual acuity was reduced, i.e., counting fingers at 1 meter in the right eye and counting fingers at 0.30 meters in the left eye. The corneal stroma was diffusely edematous, with marked thickening. The fundus could not be visualized; however, electroretinogram showed normal scotopic and photopic tracings in each eye.

Meire et al. (1998) reported 2 unrelated children with sporadic Harboyan syndrome. One was a 14-year-old boy with a visual acuity of 20/200 in both eyes in whom hearing loss was first noted at 5 years of age on routine screening; the other was a 4-year-old girl with a visual acuity of 20/100 and 20/60 in the right and left eyes, respectively, in whom audiometry revealed sensorineural hearing loss. The authors commented that the association of congenital hereditary endothelial dystrophy and sensorineural deafness may remain undetected since the hearing loss is slowly progressive with maintenance of good speech discrimination, and suggested that hearing loss could probably be detected in the first years of life if sought.

Mapping

Abramowicz et al. (2002) reported homozygosity mapping in a consanguineous Moroccan family with corneal dystrophy and perceptive deafness. They narrowed the minimal critical region to 7.73 cM between markers D20S199 and D20S437 and obtained a maximum multipoint lod score of 4.20 at markers D20S889/D20S179.

Molecular Genetics

In 3 consanguineous and 3 nonconsanguineous families with CDPD, Desir et al. (2007) identified homozygosity or compound heterozygosity, respectively, for mutations in the SLC4A11 gene (see 610206.0009-610206.0016).