✍️ AD inherited pattern
✍️ anterior segment dysgenesis and systemic abnormalities.
✍️ In 1920, Axenfeld described posterior embryotoxon and iris strands adherent to the anteriorly displaced Schwalbe’s line.
✍️ 1935 Rieger described patients with congenital iris abnormalities including iris hypoplasia, correctopia, and polycoria (Rieger anomaly)
✍️ Rieger anomaly, associated with systemic findings, such as dental, facial bone defects including maxillary hypoplasia, umbilical abnormalities, or pituitary involvement is known as Rieger syndrome.
✍️ anterior chamber angle is formed from the migration waves of the neural crest so anterior angle dysgenesis is usually associated with skin , facial bone and cartilage and meninges and endocrine abnormalities
✍️ Glaucoma occurs in 50% of cases
✍️ The syndrome has an estimated prevalence of 1/200,000.
✅ pathohistologically:
☝️ it is a monolayer of endotheilial-like cells with a Descemet-like membrane extending from the cornea, across the anterior chamber and angle structures onto the surface of the iris.
☝️ The membrane is typically found in the quadrant with associated the ectropion uveae/corectopia while the iris atrophy is found in the opposite quadrant.
✍️ 8-15% of the normal population have mild form of posterior embryotoxon without other sequelae.
✍️ the posterior embryotoxon may not be visible with the slit lamp examination and visible only with gonioscopy.
✅ Clinical picture:
✍️ARS is mainly clinical diagnosis
✍️ highly variable.
✍️ divided into ocular and non-ocular findings.
✍️ Ocular findings
☝️ Iris hypoplasia
☝️corectopia
☝️hole formation (mimicking polycoria)
☝️ prominent and anteriorly displaced Schwalbe’s line (posterior embryotoxon)
☝️ iris strands bridging the iridocorneal angle to the trabecular meshwork.
☝️ 50% has increased ocular pressure (IOP) leading to glaucoma which may develop in infancy, but usually occurs in adolescence or early adulthood, occasionally after middle age.
✍️ non-ocular findings
☝️mild craniofacial dysmorphism
* hypertelorism.
* telecanthus
* maxillary hypoplasia with flattening of the mid-face
* prominent forehead
* broad, flat nasal bridge
☝️ dental anomalies
* microdontia
* hypodontia.
☝️redundant periumblical skin.
☝️ Hypospadias in males
☝️ anal stenosis
☝️ empty sella syndrome
☝️ arachnoid cysts
☝️pituitary abnormalities
☝️growth retardation may also be observed.
✅Axenfeld-Rieger syndrome(ARS) Etiology
☝️ mutations in the transcription factor genes in 60% of cases
* PITX2 (4q25)
* FOXC1 (6p25)
✅ Axenfeld-Rieger syndrome(ARS) Differential diagnosis
☝️ iris hypoplasia (IH)
☝️ iridocorneal endothelial syndrome
* chandler
* Cogan-Reese
* Essential iris atrophy.
☝️primary congenital glaucoma (PCG)
☝️ Peters anomaly
☝️ Absence of corneal abnormalities (megalocornea, sclerocornea and corneal opacity ) are useful in distinguishing ARS from other anterior segment disorders.
☝️ regarding ICES The unilateral nature, corneal endothelial changes, manifestation in middle age, female predominance, and lack of systemic abnormalities differentiate ICE from ARS.
✅ Axenfeld-Rieger syndrome(ARS) Management
✍️ annual F/ups
☝️ slit lamp examination
☝️gonioscopy
☝️IOP measurements
☝️funduscopy
☝️ VF whenever glaucoma is suspected.
✍️ Medical Management
☝️ usually temporary measure
☝️ an adjunct to surgery
☝️ drugs
* beta-blockers
* carbonic anhidrase inhibitors
* Prostaglandin analogues may be used to lower IOP.
* Alpha-2 agonists, especially brimonidine, is contraindicated in children less than 2 years of age due to potentially serious apnea, bradycardia, hypotension, hypotonia, and CNS depression in this population.
✍️ Surgical Management
According to severity and controllability of glaucoma progression
☝️ goniotomy
☝️trabeculotomy
☝️trabeculectomy with or without anitfibrotic agents
☝️aqueous shunt procedures
☝️cyclodestructive procedures.
🛑 ARS patient may experience significant and debilitating glare or photophobia resulting from the sometimes progressive iris atrophy, polycoria, and corectopia. In these circumstances painted or tinted contact lenses may be beneficial in reducing these symptoms.
✅Axenfeld-Rieger syndrome(ARS) Prognosis
Prognosis is good, particularly in the absence of glaucoma.
