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Health Professionals Guide to Newborn Screening: Cystic Fibrosis

Health Professionals Guide to Newborn Screening

 

Cystic Fibrosis

Autosomal recessive disorder characterized by pulmonary obstruction and/or exocrine pancreatic dysfunction. The major and most severe genetic mutation causing cystic fibrosis is a three-basepair deletion (F508) in the cystic fibrosis transmembrane regulator (CFTR) gene with a resulting increase in the pancreatic enzyme immunoreactive trypsinogen.

 

Prevalence (WI): 1:4,500
Analytes Measured:

Immunoreactive Trypsinogen (IRT)

Mutation Analysis for 23 CF mutations:

NOTE: Mutation analysis is performed on the highest 4% of the daily IRT results.

ΔF508 2184delA A455E ΔI507 G542X
G551D R553X R560T 1717-1G>A R1162X
3659de1C N1303K W1282X R334W R347P
1898+1G>A R117H 621+1G>T 2789+5G>A  
G85E 711+1G>T 3120+1G>A 3849+10KbC>T  

 

Abnormal Levels: IRT > 170 ng/mL
One mutant allele
Two mutant alleles
Feeding Effect: None
Timing Effect: None
Confirmation: Sweat chloride testing by pilocarpine iontophoresis.

Treatment:

Comprehensive approach to provide postural drainage with chest percussion, inpatient and outpatient antibiotics, pancreatic enzyme replacement, proper nutrition and psychosocial support.

 

COMMENT: Screening for cystic fibrosis using the two-tiered IRT / DNA approach cannot always distinguish babies who are CF carriers from babies who are affected. Sweat Chloride testing by the CFF-approved quantitative pilocarpine inotophoresis method is recommended for all reported positive screening results, i.e. babies with either one or two mutations detected. For babies with no detectable mutations but with an IRT > 170 ng/mL, the primary care provider should be alert for persistent diarrhea, poor weight gain, chronic cough or respiratory problems. If these signs appear, or if there is a family history of CF, contact should be make with a CF specialist. It is estimated that screening for 23 CF mutations will detect 98% of the CF affected babies.

Information on treatment centers is also available on this site.


For information about other screened disorders, click on the next page button, or follow one of these links:

Argininosuccinic Acidemia (ASA) Hemoglobin Variants
Biotinidase Deficiency Homocystinuria
Congenital Adrenal Hyperplasia Hypermethioninemia
Congenital Hypothyroidism Hyperphenyalaninemia
Citrullinemia (Types I & II) Maple Syrup Urine Disease
Cystic Fibrosis Organic Acidemias (14)

Fatty Acid Oxidation Disorders (12)

 

Phenylketonuria
(Includes Biopterin Cofactor defects
of regeneration and biosynthesis)

Galactosemia Severe Combined Immune Deficiency (SCID)
Hemoglobin S-Beta Thallassemia Sickle Cell Disease
Hemoglobin S/C Disease Tyrosinemia (Types I,II, & III)

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