Harboyan Syndrome Due to Novel Mutations in the Borate Transporter Gene SLC4A11

Abstract

Purpose: : To describe a patient with Harboyan syndrome, a combination of congenital hereditary endothelial dystrophy (CHED) and sensorineural hearing loss (SNHL), who is compound heterozygous for two novel mutations in the SLC4A11 gene.

Methods: : A 25-year old man presented with bilateral corneal clouding and nystagmus at birth. He also suffered from SNHL. He underwent a full ophthalmological, ENT and systemic work-up.

Results: : Bilateral corneal clouding and nystagmus was noted at birth. He was operated (goniotomy) for congenital glaucoma at the age of 14 as the diagnosis of CHED was delayed. Hearing loss was first noticed at the age of 5 by routine screening. Extensive blood and urine analyses were unremarkable. At the age of 23, BCVA was 1/10 in the right eye and counting fingers in the left. Slit lamp examination revealed a diffusely oedematous stroma with marked thickening more pronounced in the left eye than in the right. Small, localized areas of confluent endothelial bullae could be observed in both eyes. The anterior chamber and lens were unremarkable. Fundoscopy showed no gross abnormalities of the posterior pole and retinal periphery. An ERG performed at birth was normal. DNA analysis confirmed the clinical diagnosis of Harboyan syndrome and revealed compound heterozygosity for two novel mutations in the SLC4A11 gene (c.427G>A & c.453-454insTG).

Keywords: cornea: endothelium • gene screening • genetics