Phenotypic spectrum of autosomal recessive Keratitis-Ichthyosis-Deafness Syndrome (KIDAR) due to mutations in AP1B1

Inborn errors in copper metabolism result in a diverse set of abnormalities such as Wilson disease and MEDNIK syndrome. Homozygous pathogenic variants in AP1B1 lead to KIDAR (Keratitis-Ichthyosis-Deafness Syndrome). The main phenotypic features of KIDAR are ichthyosis, keratitis, erythroderma, and progressive hearing loss accompanied by developmental delay and failure to thrive. Herein, we describe a six-and-a-half-year-old boy with KIDAR caused by a novel pathogenic variant in AP1B1 (NM_001127.4:c.1263C > A, p.Tyr421*). The proband presented with ichthyosis, erythroderma, palmoplantar keratoderma, hearing loss, and corneal scarring. He also had hypotonia, global developmental delay, and photophobia. Lastly, we review all of the previously reported cases and the clinical features associated with KIDAR.

Automated summary

Inborn errors in copper metabolism can lead to various abnormalities such as Wilson disease and MEDNIK syndrome. Homozygous pathogenic variants in AP1B1 gene cause KIDAR syndrome, characterized by ichthyosis, keratitis, erythroderma, progressive hearing loss, developmental delay, and failure to thrive. This article describes a case of KIDAR syndrome in a six-and-a-half-year-old boy with a novel pathogenic variant in the AP1B1 gene and reviews the clinical features associated with this syndrome.