Harboyan syndrome with biallelic SLC4A11 pathogenic variants misdiagnosed as congenital CMV infection

Harboyan syndrome is a rare autosomal recessive disorder characterised by congenital hereditary endothelial dystrophy (CHED), with a later onset of sensorineural hearing loss, due to pathogenic variants in the SLC4A11 gene. Congenital cytomegalovirus (CMV) may also manifest with sensorineural hearing loss and visual impairment. We present a case of a 4-year-old girl, diagnosed at birth with a congenital CMV infection, but careful phenotyping and genetic testing permitted a more likely diagnosis of Harboyan syndrome.