Is Glaucoma Hereditary?
There has been a rapid increase in our knowledge about the genetics and inheritance of glaucoma. However, we are yet to understand how the genetic mutations and abnormalities actually cause glaucoma. That said, there has been a definite correlation between certain gene abnormalities and glaucoma. This indicates that certain kinds of glaucoma may be hereditary.
This means that if someone in your family, especially a first degree relative, has glaucoma, your risk for developing glaucoma is definitely higher than the general population.
Over time, as research progresses, these genetic associations may help us find new therapies for glaucoma, as we learn more and more about the cause for glaucoma.
Glaucoma Runs in Families
Glaucoma is hereditary. If any member of your immediate family (a parent or a sibling) have glaucoma, your risk of developing early-onset glaucoma increases by almost ten times. The risk increases if your identical twin has glaucoma. In fact, doctors recommend that those with first-degree blood relatives who have glaucoma should be screened for glaucoma.
If there is a history of glaucoma surgery or blindness, this becomes even more important.
In addition, if you have glaucoma, you must inform your family members know about the diseases and its tendency to run in families. You must also encourage them to undergo a comprehensive dilated eye examination.
Early onset glaucoma
Early onset glaucoma is often hereditary. That is, most of the forms of glaucoma that affect infants, children and young adults are often inherited.
Primary congenital glaucoma
Primary congenital glaucoma affects children from birth to three years of age, and is a major cause of childhood blindness. It has been known to be associated with mutations in the CYP1B1 and LTBP2 gene. The CYP1B1 mutation, interestingly, causes glaucoma in children all over the world. In fact, it is especially prevalent in children with glaucoma the Middle East and central Europe.
This glaucoma inheritance is autosomal recessive. This means that both parents may be carriers of the mutation but do not have glaucoma. If any of their children, however, inherit both copies of the abnormal gene (one from each parent), they may have glaucoma.
Developmental Glaucoma
This kind of childhood glaucoma affects children older than three years of age. The main reason for this is the abnormal development of the eye. The genes known to be associated with these forms of glaucoma include PITX2, PITX3, FOXC1, FOXE3, PAX6, LMX1B, and MAF.
These genetic mutations are inherited in an autosomal dominant fashion. This means that half of the children in the family may be affected, since the inheriting of just one copy of the mutated gene may result in glaucoma.
Juvenile Glaucoma
A mutation of the myocilin gene may result in glaucoma in patients less than thirty five years of age. Its inheritance is also autosomal dominant. This implies that parents with this form of early-onset glaucoma may pass the mutation, and disease, to 50 percent of their children.
Age Related Glaucoma may be Hereditary
Primary Open-Angle Glaucoma
No one gene has been found to be the cause of primary open angle glaucoma, POAG, which is the most common variant of glaucoma. In fact, most researchers have found that multiple gene variants are associated with an increased risk of glaucoma. The genetic mutations linked to POAG include CDKN2B-AS, SIX1/SIX6, TMCO1, and CAV1/CAV2.
Other Forms of Open Angle Glaucoma
- Normal tension Glaucoma
It is interesting to note that the CDKN2B-AS gene and a region on chromosome 8 have been found to be associated with normal-tension glaucoma.
- Pseudoexfoliation Glaucoma
Genetic variants of LOXL1 and CNTNAP2 genes have been associated with pseudoexfoliation glaucoma.
Primary angle-closure glaucoma
Primary angle-closure glaucoma (PACG) is the second most common form of glaucoma. The genetic variants associated with this form of glaucoma are in or near PLEKHA7, PCMTD1/ST18, and COL11A1.
Glaucoma Genetics and the Future of Glaucoma Therapy
Our knowledge about glaucoma genetics and its inheritance is still not as comprehensive as to result in major treatment decisions. That said, the future holds great promise as the hereditary aspect of glaucoma is studied more and more.
- As on date, genetic testing is already available for some forms of early-onset glaucoma. This can help in early diagnosis and genetic counseling for parents-to-be.
- Even though there are no genetic treatments available currently, there is hope. Gene therapy may offer personalized treatments for those patients with genetic mutations.
- While it is not available as on date, in time, it may be possible to offer patients personalized glaucoma risk assessments and/or treatments.
