Fight for Sight-funded research has promising insights for patients with childhood eye disease, ocular coloboma

Ocular coloboma is a disease that causes part of the eye to be missing at birth, often severely affecting the patient’s vision. Currently there are no treatments for it.

A new study published in eLife and funded by Fight for Sight revealed new genes that may be responsible for the developmental errors that cause coloboma. The findings may help identify genetic defects in patients with coloboma and other birth defects.

Childhood blindness

Ocular coloboma accounts for up to 10 per cent of all childhood blindness. It can cause a distinctive keyhole-shaped pupil as it commonly results in a missing segment in the iris, the coloured part of the eye, which may extend through to the optic nerve.

Genetic causes of embryonic errors

Coloboma is the result of errors in tissue fusion – an essential process during development that is needed for the formation of the eye and many other organs of the developing embryo. Tissue fusion errors are a relatively common form of birth defect, however the genetic causes remain unknown for the majority of patients.

The scientists, led by Dr Joe Rainger of the Roslin Institute, used genetic profiling techniques to conduct the research, and in doing so were also able to identify the genes that are switched on or off during fusion. They found many of these, some of which were already known to be essential for fusion in humans, and some that were newly identified as such.

One of the newly identified fusion genes, Netrin-1 is likely to be critical in humans and other species, as well as in organs other than the eye (such as the palate, for example).

Dr Joe Rainger said: "Identifying new genes and processes involved in tissue fusion will improve our understanding of how fusion defects occur, and whether these may be preventable. The fusion genes we have revealed are also an excellent resource to support the identification of genetic defects in patient sequencing programmes."

You can read more about coloboma on our website here.