“When some parents have a genetic condition and their child is blind, the childhoods of people with related diseases often are, too,” explained University of Copenhagen professor Olavi T. Hallidi, the principal investigator of the study.

Intense darkness wasted their time.

To determine whether the organism inherits these hereditary defects due to poor daylight, the research team studied the blood from 2,704 people with inherited kidney diseases.

“All children showed defects in the gene that is needed for the kind of light-sensing process in our eyes that is controlled by our night vision. In some, the normal gene plays an imperative supporting role during the light-sensing process”, Hallidi says.

Enlarged eyes due to circadian disruption.

During the study, it transpired that the receptor of the genetic defect (HLPRSS3) can function as an epigenetic marker for an inherited disease that causes hypophysectaxis—a condition that prevents the proliferation of certain types of adult stem cells.

“As a result, the embryos of the children whose genetic defects can be caused by the disease do not develop properly. They are less sensitive to light and are perpetually unable to ensure that the light they see does not damage their eyes”, Hallfiore says.

Children who lack the enzyme essential for the light-sensing reaction show severe visual defects. Hallfiore: ‘Our results show how inherited defects in the HLA gene influence the development of the eye’.