Rieger Syndrome

Axenfeld-Rieger syndrome (ARS) represents a spectrum of diseases that involve congenital anomalies of the anterior segment of the eyes. In addition, about 50% of patients will develop glaucoma, leading to decline of vision and potential blindness. The most prominent eye defects in ARS include (1) Axenfeld anomaly, characterized by a prominent Schwalbe’s line and adherence of the iris to the cornea and trabecular meshwork, (2) Rieger anomaly, consistent with Axenfeld anomaly plus iris hypoplasia, eccentric pupils (corectopia) and/or iris holes (polycoria) and (3) Rieger syndrome, which includes Rieger anomaly as well as the non-ocular symptoms. These non-occular findings include dental hypoplasia, mild craniofacial dysmorphism, and redundant umbilical skin. Cardiac defects, limb anomalies, pituitary abnormalities, sensory hearing loss and/or mental defects may also be present. Additional disorders such as iridogoniodysgenesis, iris hypoplasia and Peter’s anomaly fall under the umbrella of ARS. ARS is fully penetrant but shows variable expression, even within a family. ARS may be caused by mutation in one of several different genes, the most common of which are the PITX2 and FOXC1 genes, encoding different transcription factors. In general, mutation in the PITX2 gene has been seen more frequently in patients with ocular and systemic anomalies, whereas mutation in FOXC1 was found in patients with isolated ocular findings