Novel mutation as a cause of anterior segment dysgenesis leading to blindness in progeny: the genetics decoded!

Abstract

Anterior segment dysgenesis (ASD) disorders comprises of spectrum of developmental conditions affecting the structures of angle of anterior chamber including cornea, iris, and lens. These conditions are characterized by both autosomal dominant and recessive patterns of inheritance often with incomplete penetrance/variable expressivity. A significant overlap among phenotypes attributed to mutations in different ASD genes is well recognized. We present a case involving a 29-year-old pregnant woman referred for genetic screening and counseling. She had a 7-year-old male child with congenital bilateral corneal opacity, and his elder sister also exhibited similar findings. Exome sequencing identified a novel variant in the CYP1B1 gene in a homozygous state, which was associated with anterior segment dysgenesis. Both parents were found to be carriers of the same variant, while the sister had the same variant in a homozygous state. Genotype–phenotype correlation was performed, and it was concluded that the novel variant could be responsible for the eye changes in both siblings. The parents sought prenatal diagnosis for the current pregnancy, which was deemed possible. This case underscores the importance of genetic testing in such rare diseases, as it can assist in early diagnosis, management, and prognosis. It also aids clinicians and parents in making decisions regarding the continuation of the pregnancy at the appropriate time.