Fragile X Can Affect Brain Function

But A Simple Blood Test Can Detect It

(CBS)  You may not have heard of the genetic disorder Fragile X but it is the most common inherited cause of mental retardation.

Fragile X is a gene disorder in which a protein, assumed to be essential for normal brain function, is missing. One in 260 women is a carrier, but because the gene for Fragile X was only discovered in 1991, the disorder frequently goes undetected.

There is a simple DNA blood test for Fragile X, but not enough doctors or parents are aware of it.

Just last week, the House of Representatives passed the Children's Health Act of 2000, which includes major funding for Fragile X research.

CBS News Correspondent Elizabeth Kaledin reports on the syndrome.

---

Katie Clapp's son, Andy, may look like any other youngster but for anyone familiar with Fragile X, his long face and broad forehead are telltale characteristics of the syndrome. Clapp was not familiar with Fragile X when Andy was born and struggled to find out what was wrong.

"I remember during the first year going back several times and worrying that he wasn't sitting up when he should have and that he was a floppy baby. And he certainly didn't crawl when he should have," Clapp says.

It took three long years of false diagnoses from neurologists, geneticists and pediatricians before a specialist in developmental delays uncovered the right answer.

"He saw him walk across the room and flap his hands a little bit," Clapp recalls. "And he said, 'You know, I think we will test for Fragile X.'"

The test came back positive.

By then, Clapp's second child Laura was 4 months old, and she, too, tested positive. Like her mother, Laura is only a carrier of the disease and at age 8 shows none of developmental and learning delays present in Andy. Carriers are not usually affected, but they are at risk of having affected children.

"I had no idea I was a carrier for Fragile X until I had my son tested, and then that led us to look at my family. And now we know that my mother, my grandmother, my uncle and cousin are all carriers," Clapp says.

Clapp has applied every ounce of her frustration toward making sure other families know to get tested. She founded Fraxa, a nonprofit organization supporting research toward effective treatment of Fragile X. And experts are studying the possibility of replacing the key protein that is missing in Fragile X, or replacing the gene.

In fact, solving Fragile X is providing powerful research models for other disorders like autism and schizophrenia.

The research could make day-to-day life easier for kids like Andy, and the door is open for a potential cure.

Says Clapp: "I do have this image - and this is just a dream - of Andy at some point saying to me, 'Thanks, Mom. I can do it now. I am going out there (to) live a good life, and I am just fine."