Genetics

Mysterious Childhood Diseases of Sephardim

Discovery of a Mutation Leads to New Genetic Tests

By Dorothy Brown

If you were watching the BBC this spring, you would have seen one of Israel’s foremost geneticists debating the issue of marriage to close family members in Doha, Qatar — at the heart of the Arab world.

At the Doha Debates Dr. Ohad Birk, who heads the Center for Human Genetics Research at the National Institute for Biotechnology in the Negev, argued that while individuals should be free to choose whom they wish to marry, they should also fully understand the genetic risks. “They either take a huge risk or they don’t take a huge risk,” he said.

He had been invited because of his groundbreaking work on genetic screening of Bedouin, North African and Iraqi populations in Israel.

His latest major discovery, announced in October 2010, identified a gene mutation for a devastating disease of infancy, carried by about one in every 40 Moroccan Jews and one in every 40 Iraqi Jews.

The disease, called Progressive Cerebro-Cerebellar Atrophy or PCCA, causes the infant’s brain to atrophy. By age two, the child is retarded and physically disabled. By three, he’s in a wheelchair, virtually vegetative.

Six months after the announcement, Israel’s health system began offering free genetic screening for the mutation to every North African and every Iraqi couple. (The test is not yet available in the United States.)

This kind of commitment to screening for a variety of genetic diseases has in the last five years brought down the infant mortality rate among Bedouins alone in Israel by one third, Birk said.

It’s all about attitude, said Birk, who also heads the Genetics Institute at Soroka Medical Center in Be’er Sheva, in a recent phone interview. For Israelis, he said, genetic screening has become “part of the culture. People get tested before they have children. It’s just routine.”

In July, he lectured in New York about the new genetic discoveries and their implications. “I’d like to shift the way people look at genetic disease,” said Birk in the interview. “Every group in the world has its genetic diseases.” And an understanding of Sephardic diseases, he said, “is lagging behind.”

In southern Israel, where the population is made up of about 200,000 Bedouins and about 800,000 mostly non-Ashkenazi Jews, Birk has made inroads into an understanding of the genetics affecting these groups. So far, he said, his team alone has found 20 genes and their specific mutations, with application for Arabs as well for Sephardic Jews.