Repetitive DNA protects against specific eye disorder

Jong de, Eiko.jpg

Small defects in the immune system lead to eye problems.

Investigators from the Radboudumc have shown that patients who suffer from blurred vision during stress have subtle changes in their immune system. The results have been published in Investigative Ophthalmology & Visual Science. 

Patients with chronic central serous chorioretinopathy (CSC) regularly suffer from blurred vision. This is a consequence of fluid leaking from the vascular layer underneath the retina, generating a bubble of fluid that distorts the path light normally takes to the retina and generates blurred vision as a consequence. The precise etiology of the disease is not known yet, but men suffer more from the condition than women and a relationship to stress, or the use of steroids has been suggested. 

(photo Eiko de Jong)

Testing a hypothesis.

Stress hormones suppress the immune system. This gave Myrte Breukink and Roos Schellevis from the department of ophthalmology the idea that in this group of patients the immune system might be suppressed. Together with ophthalmologist Camiel Boon from Leiden UMC, they collected over 200 CSC patients to test this idea. 

Repetitive DNA.

Genetic research, led by Eiko de Jong from the department of ophthalmology demonstrated that the complement system – a crucial part of the immune system – indeed functions slightly different in these patients. Especially differences in the gene C4B are apparent. If this gene is not present, patients are at considerable higher risk for getting the disease. Having multiple copies of the gene offers protection. The immune system of CSC patients is regulated in a different way compared to healthy controls. 

Immune system and eye disorders.

Other researchers have also connected copy number variations in C4 to  other eye disorders and auto-immune disorders, such as Bechet’s disease. Besides this, the gene has an effect on the level of cortisol – the endogenous stress hormone.  In their research, these investigators from Nijmegen and Leiden have demonstrated again that the immune system is involved in complex eye disorders.

Publication:

Copy number variations of the complement component C4B gene are associated with chronic central serous chorioretinopathy. Invest Ophthalmol Vis Sci. 1;56:5608-13, 2-15. 


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