Gene Explains Night Blindness

Night blindness explained by gene linked to neuropsychiatric disorders

(RxWiki News) Night blindness can be so debilitating that some sufferers struggle to drive after dark. The finding of a mutated gene that causes the vision loss in low-light environments explains how night vision is possible.

Scientists had long known that a gene called nyctalopin was responsible for night blindness, but how it worked remained mysterious.

"Don't drive at after dark if you have night blindness."

Kirill Martemyanov, an associate professor at the Florida campus of The Scripps Research Institute, said that until now understanding of the gene's role in vision had been limited. He said this is the first time a functional role for it has been pinpointed.

People see items when photons hit light-sensitive photoreceptor cells in the eye's retina. A generated nerve response occurs at contact points called synapses. Proper function there is critical, and if the signal is not transmitted properly the result is an inability to see in the dark.

Martemyanov noted that transmission speed must occur very quickly to provide clear resolution to what we see. When working correctly, people see objects clearly as they turn their heads instead of just a blur.

As part of the new research, scientists searched for proteins associated with nyctalopin in a mouse retina. They found that the protein expressed by the gene acts as a kind of molecular glue that hold key signal elements together. This allows for a rapid and intact transmission of sensory signals.

The findings suggest that the gene is responsible for coordinating assembly and delivery to the synapse, which helps make vision possible. In addition to being relevant to low-light vision, the discovery could have implications for neuropsychiatric diseases such as schizophrenia and autism because similar proteins exist in the central nervous system.

The research was published in The Journal of Neuroscience.

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Review Date: 
August 12, 2011