The Genetic Disorder, Fragile X

Fragile X, you may not have heard of it, but it is the most common inherited cause of mental retardation. Just last week, the House of Representatives passed the Children's Health Act of 2000, which includes major funding for Fragile X research. Here with more on the syndrome is CBS' Elizabeth Kaledin.

Fragile X is a genetic 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.

Katie Clapp's son Andy may look like a normal youngster, enjoying a little TV after school. But for anyone familiar with Fragile X, Andy's long face and broad forehead are telltale characteristics of the syndrome. Clapp was not familiar with the 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," says Clapp.

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 and he said you know I think we will test for Fragile X," says Clapp. "It 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 the 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 lead us to look at my family and now we know that my mother, my grandmother, my uncle and cousin are all carriers."

Clapp has turned every ounce of her frustration towards making sure other families know to get tested. She founded Fraxa, a non-profit 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.

"Fragile X is probably the best example of what is going on with the gene," says Dr. Randi Hagerman at the University of Colorado School of Medicine. "How it effects brain structure, and then how that impacts brain behavior on both learning and emotional difficulties."

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

"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 a going out there and live a good life and I am just fine," says Clapp.

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