Friday, June 16, 2006

Section 5-C: Risk factors for childhood glaucoma

Childhood glaucoma usually refers to those that occur very early in life (usually under the age of 2 years). It is also commonly referred to as infantile or congenital glaucoma (see Fig 5-3). When glaucoma occurs between the ages of 4 - 35 years, it is usually referred to as “juvenile” glaucoma.

Figure 5-3 (same as 4-10). This young girl has congenital glaucoma in her left eye, which is noticeably larger than the right eye due to increased intraocular pressure.

Infantile glaucoma is a rare disease; it occurs in approximately 1 in 10,000 live births. Infantile glaucoma can occur in isolation, or along with other ocular or systemic abnormalities (for more detail, see Chapter 10). When it occurs in isolation, it is called primary infantile (or congenital) glaucoma (Figure 5-3). Primary infantile glaucoma occurs more commonly in boys than in girls (at the ratio of 3:2); however in Japan the gender ratio may be reversed (2:3 for boys:girls). While most of them occur without family history, approximately 10% have positive family history. If the first child has the disease, the risk of disease for the second child is about 3%. If the first 2 children have the disease, the risk for the third child is up to 25%. Thus, all siblings of an affected child should be examined closely by a pediatric ophthalmologist. Recently, mutations in the CYP1B1 gene on chromosome 2 has been found to be associated with congenital glaucoma. In the future, we may discover additional genes responsible for congenital glaucoma.

Juvenile glaucoma presents between the ages of 4 and 35, and usually associated with very high IOP. They typically have very strong positive family history of glaucoma with several older members of the family having been affected by the disease. Mutations in the gene, Myocilin (sometimes called TIGR) on chromosome 1, have been found to be associated with patients with juvenile glaucoma. If you have a strong positive family history of infantile or juvenile glaucoma, it would be reasonable to be screened for glaucoma by an eye doctor at a younger age.

References

  1. Allingham RR, Damji K, Freedman S, Moroi S, Shafranov G. Clinical Epidemiology of Glaucoma In: Shield’s Textbook of Glaucoma. 5th Ed. Lippincott Williams and Wilkins, Philadelphia, p170-190, 2005
  2. Allingham RR, Damji K, Freedman S, Moroi S, Shafranov G. Pupillary-Block Glaucomas In: Shield’s Textbook of Glaucoma. 5th Ed. Lippincott Williams and Wilkins, Philadelphia, p217-234, 2005
  3. Kwon YH, Caprioli J: Primary Open Angle Glaucoma. In: Duane’s Clinical Ophthalmology, Tasman W, Jaeger EA, eds.; J.B. Lippincott Co., Philadelphia Chapter 52:1-30, 1999
  4. Allingham RR, Damji K, Freedman S, Moroi S, Shafranov G. Molecular Genetics of Glaucomas In: Shield’s Textbook of Glaucoma. 5th Ed. Lippincott Williams and Wilkins, Philadelphia, p163-169, 2005
  5. Alward, WLM. Glaucoma: The Requisites in Ophthalmology, Mosby, St. Louis, 2000

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