analysis molecular genetics English

Glaucoma – Panel diagnostics

OMIM: 137750, 137760, 231300, 613086
Diagnostic method:

Sequencing: BEST1, CYP1B1, FOXC1, LTBP2, MYOC, OPTN, PAX6, PITX2, TBK1, TEK, WDR36 (<25kb Panel) CNV analysis: BEST1, CYP1B1, FOXC1, PAX6, PITX2

Samples required:

2 ml EDTA blood

Duration of analysis: 6-8 Wochen

Glaucoma describes a group of eye diseases in which the optic nerves are increasingly damaged. Glaucoma is one of the most common causes of irreversible blindness. Other symptoms include increased intraocular pressure, increasing enlargement of the eye (buphthalmus) and abnormal sensitivity to light (photophobia). Glaucoma usually develops in older adults, where the risk can be influenced by a variety of diseases such as high blood pressure (hypertension) and diabetes mellitus, but also by a genetic disposition. Glaucoma is therefore a multifactorial disease based on various factors, both genetic and others.

One speaks of „early onset glaucoma“ if the disorder occurs before the age of 40 (hereditary / primary open-angle glaucoma, POAG). In this case degenerative changes impair aqueous humor drainage, which increases the intraocular pressure (IOP). The risk of early onset glaucoma largely depends on inheritance. If glaucoma occurs before the age of 5 with no other associated abnormalities, it is called primary congenital glaucoma. Congenital glaucoma is a developmental glaucoma, that is caused by an abnormal development of the drainage channels of the eye. In countries with a low rate of consanguinity, like Germany, autosomal recessive inherited congenital glaucoma usually occurs sporadically. Up to now, especially mutations in the gene CYP1B1 have been described with congenital glaucoma. CYP1B1 belongs to the cytochrome P450 family and is thought to play a role in the secretion of fluid inside the eye. Furthermore, mutations in the genes LTBP2, MYOC and TEK have been described several times. Glaucoma can also occur in connection with isolated aniridia (PAX6 gene, hypoplasia of the iris). In addition to the partial or complete absence of the iris, aniridia can also lead to glaucoma. Glaucoma can also be associated with various chromosome aberrations (e.g. trisomy 18) or as part of a genetic syndrome (such as Axenfeld-Rieger Syndrome, genes FOXC1, PITX2). Other genes that are associated with hereditary glaucoma are BEST1, OPTN, TBK1 and WDR36.

Types of glaucoma:

1. hereditary/primary open-angle glaucoma (POAG):

  • before the age of 40
  • genes: MYOC (AD), CYP1B1 (AR), BEST1 (AD), OPTN (AD), TBK1 (AD), WDR36 (AD/AR)

2. primary congenital glaucoma (PCG, early onset glaucoma):

  • before the 5th year of life
  • genes: CYP1B1 (AR), LTBP2 (AR), MYOC (AD) (questionable, known in combination with CYP1B1 mutation), TEK (AD)

3. as an associated symptom of other diseases:

  • Axenfeld-Rieger Syndrome: genes: FOXC1 (AD), PITX2 (AD)
  • Aniridia/Peters anomaly: gene: PAX6 (AD)

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