FW: [CFSupport] Very Interesting CF Article

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Thanks Becky!!!!

, Agnes, others

This might help in your cause as well. Copy & add to the pile of

papers.........

LOVE & HUGS, grandmomBEV

[CFSupport] Very Interesting CF Article

Cystic Fibrosis Gene Mutations Missing From Some Cases A new study from

s Hopkins finds that some patients diagnosed with cystic fibrosis

(CF) lack any of the more than 1,000 reported disease-causing mutations

in the only known CF gene. Scheduled for presentation Oct. 18 at the

annual meeting of the American Society for Human Genetics in Baltimore,

the findings also recently appeared in the New England Journal of

Medicine. The discovery may mean that another gene, as yet unidentified,

is to blame for these cases, or perhaps these patients really have

another, unknown disease, despite the similarity of symptoms, the

researchers suggest. Loss of the function of a protein called CFTR was

identified more than a decade ago as the cause of CF, a life-shorten!

ing disease characterized by frequent, severe lung infections. In less

severe cases, known as " non-classic " CF, patients retain some working

CFTR, but not at normal levels. Over the years, scientists have linked

these conditions to more than 1,000 changes in the gene for CFTR. " Our

findings should lead to a discussion about what is, and is not,

non-classic cystic fibrosis, " says Garry Cutting, M.D., director of the

DNA Diagnostic Lab at the McKusick-s Institute of Genetic Medicine

at Hopkins. " Hopefully, extensive clinical evaluation of patients

without identifiable changes in the gene for CFTR will improve diagnosis

and treatment of cystic fibrosis and cystic fibrosis-like conditions. "

In the new study, of 74 patients diagnosed with non-classic CF and

referred to the Cystic Fibrosis Foundation Genotyping Center at Hopkins,

detailed genetic analysis showed that 29 had mutations in both copies of

the CFTR gene, 15 had only a single mutation and 30 had no detectable

chan! ges in their CFTR genes. (One copy is inherited from each parent.)

Cutting says other researchers now report the same observation. " These

patients were referred by physicians experienced with cystic fibrosis,

and we expected to find a causative mutation in each copy of each

patient's CFTR gene, " says Cutting, who also heads the genotyping

center. " While it's possible we could have missed some mutations, we

believe they just weren't there to be found in these patients. " The

researchers looked for changes in the CFTR gene in areas that carry

instructions for the CFTR protein and those that control the expression

of the gene. It might be possible that changes to the CFTR protein,

unrelated to the sequence of its gene (so-called " epigenetics " ), are at

the root of these patients' conditions. To cause disease, any changes

must reduce or alter how the CFTR protein works. In classic CF, there's

no working CFTR protein, and a thick mucous forms that traps bacteria in

the airways, cau! sing infections. In the non-classic version, the

theory held that some working CFTR protein remained to transport charged

atoms and water into and out of cells, while symptoms run the gamut from

mild to severe. First surprised that many patients lacked any mutations

in their CFTR genes, the scientists were surprised again when symptoms

were the same for these patients and those with one or two CFTR

mutations. For each measurement, including the standard test for CFTR

function that measures the amount of salt in sweat, each group looked

like the others. " Once we saw that we had a large number of patients

without changes in CFTR, we thought we'd be able to demonstrate that

they had a different condition, " says Cutting. " But we couldn't. " The

Cystic Fibrosis Foundation Genotyping Center at s Hopkins was

launched in 1998 to look for genetic changes responsible for cases of

non-classic cystic fibrosis that couldn't be explained by the most

common known mutations. The Hopkins ! researchers are putting together a

detailed account of each patient's symptoms, biochemical and

electrophysiological measurements, genetic status, and possible

non-genetic contributors to find subtle differences between the groups

that will allow physicians to distinguish between conditions linked to

CFTR mutations and those that aren't. The study was funded by the Cystic

Fibrosis Foundation and the National Institutes of Health. Authors on

the paper are Groman, Meyer, Pamela Zeitlin, and

Cutting, all of Hopkins; and Wilmott, St. Louis University School

of Medicine.

Becki

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