SNP Shot: Genomic Insights

Axenfeld-Rieger syndrome mainly affects the eyes, but can also involve other areas of the body. It's marked by abnormalities in the anterior segment, which is the front part of the eye. For instance, the iris (the colored part of the eye) may be thin or underdeveloped. The iris typically has one central opening, the pupil, for light to enter. However, individuals with Axenfeld-Rieger syndrome may have a pupil that is displaced (corectopia) or multiple openings in the iris that resemble several pupils (polycoria). The condition can also lead to corneal abnormalities, affecting the clear outer layer of the eye.

Approximately half of those affected by Axenfeld-Rieger syndrome will develop glaucoma, a serious condition characterized by elevated pressure within the eye. When glaucoma is associated with this syndrome, it typically appears in late childhood or adolescence, though it can occur earlier in infancy. Glaucoma can result in vision impairment or blindness.

Axenfeld-Rieger syndrome can also manifest with symptoms impacting other body parts. Common facial characteristics include widely set eyes (hypertelorism), a flattened mid-face with a broad, flat bridge of the nose, and a prominent forehead. Dental issues, such as abnormally small teeth (microdontia) or a reduced number of teeth (oligodontia), are also linked to the condition. Some individuals may present with extra skin folds around their belly button (redundant periumbilical skin). Less frequent features can involve heart defects, hypospadias (where the urethra opens on the underside of the penis), anal stenosis (narrowing of the anus), and pituitary gland abnormalities potentially leading to slowed growth.

Scientists have identified at least three types of Axenfeld-Rieger syndrome, categorized as types 1, 2, and 3, based on their underlying genetic cause.

Inheritance:

The condition follows an autosomal dominant inheritance pattern. This means that only one copy of the mutated gene in each cell is enough to cause the disorder.