New Test Panel for 31 Cystic Fibrosis Mutations

The need for more cystic fibrosis (CF) testing, current testing guidelines, and a new test panel were discussed during a presentation by Cindy WalkerPeach, Ph.D., at the annual meeting of the American Association for Clinical Chemistry (AACC) in Philadelphia (PA, USA).

Dr. WalkerPeach noted that more than 10 million Americans are unknowing, asymptomatic carriers of CF. When one carrier with a certain disease allele mates with another who carries the identical disease allele, a process of recombination produces an offspring with the double mutation necessary to cause the disease. The American College of Obstetrics and Gynecology (ACOG) and other groups have examined all known mutations and have recommended that all individuals considering conception be screened for the 25 most likely to occur.

A new bead-array test panel available in 2004 evaluates 31 CF mutations, including the 25 recommended by ACOG. The test requires only that genomic DNA be taken from the patient, usually through a blood draw. The genomic DNA is isolated and single-tube polymerase chain reaction (PCR) amplification of the DNA is performed against the 31 different mutations.

In one single reaction, the PCR products are hybridized to probes tethered onto small color-coded microspheres. Each microsphere is run through a laser beam that identifies the presence of a mutation. After hybridization, all ACOG mutations are screened in 15 seconds. A big benefit of this test is that laboratories can run thousands of tests each week, noted Dr. WalkerPeach, of Ambion Diagnostics (Austin, TX, USA), which developed the new test panel.



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