The Melbourne five-year-old suffers from a condition so rare it is yet to be named – and now he is helping scientists save others from the same fate. Travis’s case has baffled doctors, who initially were unable to explain his autistic-like symptoms. His mother, Michelle, said her son, who also cannot walk, talk or eat without assistance, “has had every test known to man”. Experts now believe a single and unidentified gene – carried only by female family members and only affecting males – is responsible.
Geneticist Tiong Tan said the Holdsworths were the only known carriers of the gene in the world. “I have presented Travis’s case nationally and internationally, and no other geneticist has said they’ve seen a family with this,” he said.
Dr Tan and interstate colleagues are trying to isolate the mysterious gene causing Travis’s condition. He said finding the gene, on the X chromosome, was like finding a single house on a map of the world. “We have narrowed it down to the suburb, but within that suburb there are lots of streets and lots of houses,” said Dr Tan, of Murdoch Children’s Research Institute. Travis and his relations will be crucial in solving the medical mystery. Two cousins, both male and from his mother’s side of the family, died of the same condition at age 10. In an effort to prevent more children being born with Travis’s condition, DNA from 12 family members has been collected and stored.
All samples will be tested when the defective gene is identified, revealing the carriers. “By looking at the family and who’s affected and how they are connected, it’s very likely that (Travis’s condition) is being caused by just one gene on the X chromosome,” Dr Tan said.
“Females carry the gene, but it’s boys who are affected because they only have one X chromosome. Females have two, so they have a backup copy (cancelling out the faulty version).” Mrs Holdsworth said her family could make medical history. “We have been told the gene could be named after our family when they find it,” she said.
“But I don’t care about that — the point is we may be able to help other people.” But nothing has stopped Travis. “Despite what he has gone through, he is just such a happy and calm and brave boy. We all love him so much,” Mrs Holdsworth said.
HeraldSun Australia
http://www.news.com.au/heraldsun/story/0,21985,23974248-2862,00.html
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