Journal of Genetic Counseling, Vol. 8, No. 3, 1999

Update and Review: Cystic Fibrosis Trisha Brown1'3 and Elinor Langfeider Schwind2

Cystic fibrosis (CF) is one of the most commonly inherited recessive disorders in U.S. Caucasians, with a carrier frequency of approximately 1 in 29. Genetic counseling and CF mutation analysis has traditionally been offered to the affected patient and his/her extended family, in keeping with policy statements from professional organizations (ASHG, NSGC, ACOG). The target population for CF testing and counseling may be evolving after the release of the 1997 National Institutes of Health Consensus Statement, Genetic Testing for Cystic Fibrosis, which recommends that CF screening be offered to all preconceptional and pregnant couples. Genetic counseling for CF is complicated by reports of polymorphisms in the CF gene that are associated with symptoms that do not meet the diagnostic criteria for CF, such as bilateral congenital absence of the vas deferens, bronchiectasis, and idiopathic pancreatitis. To aid genetic counselors with these issues, this review explores the symptoms ofCF, patient management, gene function, genetics, genotype/phenotype correlation, and genetic counseling issues. KEY WORDS: cystic fibrosis; genetic counseling; genotype/phenotype.

INTRODUCTION As our understanding of genetic disease expands, the underlying mechanisms of "simple" Mendelian disorders are turning out to be increasingly complex. Cystic fibrosis (CF) is one such disorder where research has shown an intricate relationship between genotype and phenotype. For example, modifier genes may exist that influence the phenotype of CF patients (Rozmahel etal., 1996). In addition, "benign" cystic fibrosis transmembrane conductance regulator (CFTR) polymorphisms can be associated with mild CF symptoms, such as isolated congenital absence of the 'LabCorp, Auburn, California. St. Vincent's Hospital, Cystic Fibrosis Center, New York, New York. Correspondence should be directed to Trisha Brown, LabCorp, 11965 Heritage Oak Place, Auburn, CA 95603.

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Update and Review: Cystic Fibrosis.

Cystic fibrosis (CF) is one of the most commonly inherited recessive disorders in U.S. Caucasians, with a carrier frequency of approximately 1 in 29. ...
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