The diagnosis and phacoemulsification in combination with intraocular lens implantation for an Axenfeld-Rieger syndrome patient with small cornea: a case report

Ophthalmological Manifestations of Axenfeld-Rieger Syndrome: Current Perspectives

Axenfeld-Rieger syndrome (ARS) is a rare congenital disease that is primarily characterized by ocular anterior segment anomalies but is also associated with craniofacial, dental, cardiac, and neurologic abnormalities. Over half of cases are linked with autosomal dominant mutations in either FOXC1 or PITX2, which reflects the molecular role of these genes in regulating neural crest cell contributions to the eye, face, and heart. Within the eye, ARS is classically defined as the combination of posterior embryotoxon with iris bridging strands (Axenfeld anomaly) and iris hypoplasia causing corectopia and pseudopolycoria (Rieger anomaly). Glaucoma due to iridogoniodysgenesis is the main source of morbidity and is typically diagnosed during infancy or childhood in over half of affected individuals. Angle bypass surgery, such as glaucoma drainage devices and trabeculectomies, is often needed to obtain intraocular pressure control. A multi-disciplinary approach including glaucoma specialists and pediatric ophthalmologists produces optimal outcomes as vision is dependent on many factors including glaucoma, refractive error, amblyopia and strabismus. Further, since ophthalmologists often make the diagnosis, it is important to refer patients with ARS to other specialists including dentistry, cardiology, and neurology.

A novel variant in FOXC1 associated with atypical Axenfeld-Rieger syndrome

Mutations in the Forkhead Box C1 (FOXC1) are known to cause autosomal dominant hereditary Axenfeld-Rieger syndrome, which is a genetic disorder characterized by ocular and systemic features including glaucoma, variable dental defects, craniofacial dysmorphism and hearing loss. Due to late-onset of ocular disorders and lack of typical presentation, clinical diagnosis presents a huge challenge. In this study, we described a pathogenic in-frame variant in FOXC1 in one 5-year-old boy who is presented with hypertelorism, pupil deformation in both eyes, conductive hearing loss, and dental defects. By whole exome sequencing, we identified a 3 bp deletion in FOXC1, c.516_518delGCG (p.Arg173del) as the disease-causing variant, which was de novo and not detected in the parents, and could be classified as a "pathogenic variant" according to the American College of Medical Genetics and Genomics guidelines. After confirmation of this FOXC1 variant, clinical data on Axenfeld-Rieger syndrome-associated clinical features were collected and analyzed. Furthermore, Although the affected individual present hearing loss, however, the hearing loss is conductive and is reversible during the follow-up, which might not linke to the FOXC1 variant and is coincidental. Routine examination of FOXC1 is necessary for the genetic diagnosis of hypertelorism-associated syndrome. These findings may assist clinicians in reaching correct clinical and molecular diagnoses, and providing appropriate genetic counseling.