Gene for nanophthalmos identified

BALTIMORE — A human gene mutation that causes nanophthalmos has been identified, according to researchers at Johns Hopkins University.

Nanophthalmos can be caused by an alteration in the MFRP gene, the researchers said.

“The MFRP protein is only made in a tiny portion of the human eye, and it can alter eye refraction or focus,” said Olaf Sundin, PhD, in a press release from Johns Hopkins.

In nanophthalmos, a mutation in MFRP “completely wipes out the function of the protein coded for by the gene,” the press release said. The disease’s secondary complications include glaucoma and detached retinas, Dr. Sundin said.

Dr. Sundin and colleagues at Johns Hopkins’ Wilmer Eye Institute identified the gene by studying members of a family affected by the condition. In a study published in the Proceedings of the National Academy of Sciences, the researchers describe their findings from studying the DNA and family tree of an Amish-Mennonite woman who was blind in one eye. The woman had several living relatives who also suffered from nanophthalmos, as well as four deceased relatives.

Mutant MFRP has previously been identified as a cause of retinal degeneration in mice, but it has not previously been linked to nanophthalmos, Dr. Sundin said. Because of the different function the gene plays in mice, it was not assumed to alter refraction in humans, Dr. Sundin said.