CHAPTER 22

Pediatric Glaucomas

Pediatric glaucomas are a heterogeneous group of diseases that may result from an isolated congenital abnormality of the aqueous outflow pathways (primary glaucoma) or from abnormalities affecting other regions of the eye (secondary glaucoma). A variety of systemic abnormalities are associated with pediatric glaucoma. Primary congenital glaucoma (PCG) is the most common type of childhood glaucoma. BCSC Section 10, Glaucoma, also discusses the topics covered in this chapter.

Genetics

Although PCG usually occurs sporadically, it may be inherited as an autosomal recessive trait. When no other family history of PCG exists, the chance of an affected parent having an affected child is approximately 2%. Four chromosomal loci for PCG have been identified: GLC3A on band 2p21, GLC3B on 1p36, GLC3C on 14q24.3, and GLC3D on 14q24.3. Two genes, LTBP2 (at the GLC3D locus) and CYP1B1 (at the GLC3A locus), have been shown to cause PCG. Populations in which consanguinity is common have higher incidences of PCG, especially those in which the carrier rate of the CYP1B1 gene is high. Individuals who carry the CYP1B1 gene but who are nonpenetrant for PCG remain at higher risk for adult-onset glaucoma.

Juvenile open-angle glaucoma (JOAG) is inherited as an autosomal dominant trait and has been linked to the GLC1A myocilin gene (MYOC), which is also responsible for some adult open-angle glaucomas.

The genetic causes of many conditions associated with secondary childhood glaucoma have been identified; they are discussed in the chapters associated with their primary conditions.

Suri F, Yazdani S, Narooie-Nejhad M, et al. Variable expressivity and high penetrance of CYP1B1 mutations associated with primary congenital glaucoma. Ophthalmology. 2009; 116(11):2101–2109.

Classification

Several classifications for pediatric glaucomas have been proposed; they are based on ocular anatomy, age of onset, associated systemic disorders, and inheritance. Most classifications distinguish between primary and secondary glaucomas. The World Glaucoma Association recently approved a new classification system (Table 22-1).

Table 22-1