Study identifies genetic cause linked to juvenile glaucoma risk
· News-MedicalA major international study led by Flinders University has identified a genetic contributor to juvenile glaucoma.
Published today in leading US journal JAMA Ophthalmology, the study marks another important step towards treating multiple forms of glaucoma with the support of genetic testing. While glaucoma typically affects older adults, many people are unaware it can affect younger people too.
Ophthalmology experts at Flinders University, led by Professor Jamie Craig, Dr Emmanuelle Souzeau and PhD candidate Giorgina Maxwell, say the latest findings add to a growing body of evidence on the causes of this leading cause of blindness worldwide.
Mrs Giorgina Maxwell, corresponding author, genetic counsellor at Flinders University's Department of Ophthalmology, South AustraliaThis study highlights the potential for routine testing of FOXC1 duplication as part of the genetic testing process, particularly in families with a history of this form of juvenile glaucoma."
"This is important information for family members too. If a person is found to have the extra copy of the gene known as FOXC1, their first-degree blood relatives (parents, siblings and children) have up to a 50% chance of also having it.
"Identifying family members who are at risk allows earlier monitoring and treatment, helping to prevent vision loss from glaucoma."
Juvenile open-angle glaucoma (JOAG) is a form of early-onset primary glaucoma affecting individuals before the age of 40 years old. It was previously linked to other genetic causes.
Before this latest study, the prevalence of FOXC1 duplication and its presentation had not been assessed among large cohorts of patients diagnosed with JOAG.
A total of 594 JOAG patients were tested from genetic databases in the US (Massachusetts Eye and Ear) and Australia and New Zealand Registry of Advanced Glaucoma (ANZRAG), with 20 individuals from 10 families identified with this FOXC1 duplication.
"Across these two large databases, this specific genetic duplication appeared frequently, confirming its connection to this condition, which is often difficult to diagnose," says Matthew Flinders Distinguished Professor Craig, from the College of Medicine and Public Health.
"Glaucoma is a serious disease with devastating consequence and no detectable early symptoms.
"Fortunately, glaucoma is a treatable condition if discovered early. Eye drops, laser and surgery are all effective interventions that can stabilise, slow or prevent disease progression."
Dr Souzeau adds that juvenile glaucoma is often underdiagnosed.
"Identifying the genetic cause in these families is critical for diagnosis and prevention," says Dr Souzeau, who conducts screening for the ANZRAG database at Flinders University.
Historically, detecting early-stage glaucoma has been challenging, as is predicting which glaucoma patients will progress to severe vision loss. Some patients whose sight could have been saved are treated too late, while other patients who will never develop severe glaucoma are unnecessarily investigated, monitored and treated.
Glaucoma affects an estimated 80 million people globally, including an estimated 300,000 Australians – many of whom may not be aware of it.
Anyone may develop glaucoma, but the incidence increases with age. According to Glaucoma Australia, about 1 in 10,000 babies are born with glaucoma, by age 40 about 1 in 200 have glaucoma, rising to 1 in 8 at age 80.
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