Harboyan Syndrome

At a glance

A very rare condition characterized by corneal opacities present at birth and progressive neural deafness. The deafness usually does not occur until the second or third decade of life. However, the use of audiometry already shows hearing loss in the first decade of life. 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.

Synonyms

CHED1; Corneal Dystrophy Perceptive Deafness; Congenital Endothelial Dystrophy and Progressive Neural Deafness Syndrome.

Incidence and genetic inheritance

Less than 30 cases have been reported worldwide. This is an autosomal recessive inheritance as a result of a mutation of the SLC4A11 gene that is located on chromosome 20 (20p13-12). About half of reported cases occur sporadically and the rest have been reported in offspring of consanguineous matings.

Clinical aspects

Features involve eyes (corneal clouding or opacity, abnormal corneal structure, severe visual loss, glaucoma, buphthalmos). Sensory neural deafness also occurs but later in age.

Anesthetic considerations

Avoid ototoxic drugs. Eye care protection is necessary because of buphthalmos. Medications that might increase eye pressure, such as atropine, succinylcholine, and ketamine, should be avoided.

Other condition to be considered

• Congenital Endothelial Corneal Dystrophy Syndrome 2 (Corneal Dystrophy Congenital Endothelial Syndrome): This disorder must be distinguished from the Harboyan Syndrome in which deafness does not occur. It is allelic to simple, congenital endothelial corneal dystrophy and is another autosomal recessive disorder. Corneal clouding is usually evident at birth and most reported cases in the first decade of life. The presence of corneal edema is usually progressive and often leads to stromal scarring, visible neovascularization, and deposition of plaques at a later time. However, no anatomic abnormalities of the anterior chamber angle have been observed and glaucoma does not occur in comparison to CHED1.

References