OMIM ID:
Glaucoma, Open Angle, Juvenile
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Primary open angle glaucoma is a genetically and clinically heterogeneous condition. The type described here often has its onset in juveniles, much earlier than the usual type, and is much more rare. Onset is often in the second or third decade with an average age of onset of 18 years. It is rare for this form of POAG to be diagnosed after 40 years of age. IOP is commonly as high as 50 mmHg and the pressure is difficult to control. Glaucomatous changes in the optic nerve progress rapidly. The usual pharmacologic agents can be helpful early but surgical control is often required. Myopia is common (87%) but no anterior chamber anomalies are present. Juvenile POAG is more common in African Americans.
Systemic Features
No systemic abnormalities have been reported.
Genetics
Inheritance
Juvenile onset open angle glaucoma, GLAC1A, is inherited in an autosomal dominant pattern with high penetrance. It is caused by a mutation in MYOC located at 1q21-q31. The usual adult onset glaucoma is caused by different mutations.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission