Tuesday, January 5, 2010

Tests for rare gene diseases

WASHINGTON - AT HIS first birthday, John Klor could not sit up on his own. A few months later, he was cruising like any healthy toddler - thanks to a special diet that is treating the boy's mysterious disease.

Doctors ordered a vegan diet - only fruits, vegetables and specially processed pastas - with no more than 6g of protein daily. John drinks a formula containing creatine and other missing nutrients.

What doctors initially called cerebral palsy instead was a rare metabolic disorder assaulting his brain and muscles, yet one that's treatable if caught in time. Urged by John's family, Duke University researchers are working on a way to test newborns for this disease, called GAMT deficiency.

It is part of a growing movement to add some of the rarest of rare illnesses - with such names as bubble-boy disease, Pompe disease, Krabbe disease - to the battery of screenings given to US babies hours after birth. But just how many illnesses can that tiny spot of blood pricked from a baby's heel really turn up? And not all are treatable, so when is population-wide testing appropriate?

'Families go through these odysseys of diagnosis' to learn what's wrong with a child, says Dr Alan Fleischman of the March of Dimes, who is part of a government advisory committee studying what to add to the national screening list. Often, 'they argue that they would have been better off knowing even if there were no treatments.'

Since 2004, specialists have urged that every US newborn be tested for 29 rare but devastating genetic diseases, using that single heel-prick of blood, to catch the fraction who need fast treatment to avoid retardation, severe illness, even death. -- AP

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