Primary open angle glaucoma juvenile onset 1
Other Names:
JOAG1; Glaucoma 1, open angle, A; GLC1A; See More
Categories:
Congenital and Genetic Diseases; Eye diseases
Summary
Disease definition
Juvenile glaucoma (JG) is a rare autosomal dominant open angle glaucoma, characterized by early onset, severe elevation of intra ocular pressure of rapid progression, leading to optic nerve excavation and, when untreated, substantial visual impairment.
Epidemiology
In the United States, it is estimated to occur in 1/50,000 individuals.
Clinical description
JG typically presents between the ages of 10 to 35 years; the average age of diagnosis is around 18 years. Patients are initially asymptomatic and are often discovered incidentally on a routine examination. JG is generally bilateral; there can be a marked asymmetry between the two eyes. The intraocular pressure increases progressively leading to optic nerve excavation and eventually, substantial visual impairment and field loss.
Etiology
JG is caused by impaired outflow of aqueous humor through the trabecular meshwork and into the Schlemm canal. Mutations in CYP1B1 (2p22.2) and MYOC (1q23-q24) genes have been found in patients with JG. MYOCgene codes for the glycoprotein myocilin that is found in the trabecular meshwork and ocular tissue and mutations are disease-causing.
Diagnostic methods
The diagnosis is suspected with the presence of clinical features such as increased intraocular pressure and optic nerve excavation. On gonioscopy the angle appears normal. Typical features of primary congenitalglaucoma such as corneal edema and Haab’s striae are not present. The refraction test reveals myopia. Typical glaucomatous field defects can be documented. Optic nerve head shows glaucomatous optic neuropathy.
Differential diagnosis
Differential diagnoses include other forms of open angle glaucoma that can occur at any age, late recognized congenital glaucoma (see this term), steroid induced glaucoma, traumatic glaucoma and inflammatory glaucoma.
Genetic counseling
Transmission is autosomal dominant with high penetrance. Genetic testing can be used to identify family members at risk of developing JG.
Management and treatment
Medical therapy (carbonic anhydrase inhibitors, beta blockers, prostaglandin analogues, adrenergic agonists) is often useful in the treatment of JG. When the condition becomes unresponsive to medications, angle surgery (goniotomy, trabeculotomy), filtration surgery (trabeculectomy), LASER treatment (angle laser surgery or cyclodiode laser therapy) and/or aqueous shunt devices can be considered.
Prognosis
Prognosis is good in patients diagnosed and treated early.
Source:
https://rarediseases.info.nih.gov/diseases/9485/primary-open-angle-glauc…
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