Cystic Fibrosis and CF Newborn Screening in Texas Cystic Fibrosis
Grand Rounds
December 4, 2009
• Genetic disease
• Altered gene on long arm of
chromosome 7
• autosomal recessive inheritance
• Incidence by ethnic background
Caucasian ~1/3000
Hispanic ~1/6000
African American 1/10,000
• ~30,000 people in the USA1
• ~70,000 people worldwide
John Saito, MD, FAAP, FCCP
Cook Children’s Physician Network
Source: 1 Cystic Fibrosis Foundation, 2008
CF Newborn Screening Director
Cystic Fibrosis Transmembrane Conductance Regulator
(Chloride Ion Channel)
Wild-type, CFTR is transcribed into mRNA followed by posttranslational modifications including proper folding,
glycosylation, and trafficking via the Golgi apparatus to cell membrane where it functions as a regulated chloride channel.
Class 1 mutations (G542X), contain premature stop mutations that create truncated mRNA.
Class 2 mutations (F508), misfolded and unable to escape the endoplasmic reticulum.
•Results in defective production of CFTR protein faulty transport of salt in multiple organ systems Class 3 mutations (G551D), reach the cell membrane but the channel is not properly activated.
Class 4 mutations (R347P), reach the cell surface, channel can be activated but have decreased chloride conductance.
Class 5 mutations (3849 10 kb C→T), incorrect splicing resulting in decrease abundance of CFTR (milder phenotype).
Pulmonary Impact of CFTR Defect
Bronchoscopy of CF airway with thick mucus
Video: Impaired Mucociliary Clearance
Source: Cystic Fibrosis Foundation Search for a Cure, 2004
Pulmonary Disease in CF Pulmonary Disease and Lung Function Decline
Median Percent Predicted FEV1 vs Age,
Impaired Knudson Equations 1990
Bronchial
Mucociliary
Obstruction 100
Clearance
90
80
Infection Inflammation
70
Normal at birth 60
Bronchiectasis
50
40
6 8 10 12 14 16 18 20 22 24 26 28 30
1990
Pulmonary Disease and Lung Function Decline CF Mortality
Infants and children
are still dying of CF
Mortality Intestinal Malabsorption in CF
Severe CF Malnutrition at Diagnosis
(3 month old diagnosed in 2001 in a non-CF newborn screening state)
non- Multi-
Multi-Factorial
• 85% CF pts have exocrine pancreatic insufficiency with malabsorption of fat and fat-
soluble vitamins (A, D, E, K).
Pancreatic Enzyme Replacement Therapy (PERT)
•Enzyme doses up to 2,500 IU lipase units/meal
•Patient should tolerate a normal to high-fat diet without abdominal pain, distension, or
Potentially fatal protein-energy malnutrition with salt depletion abnormal or excessively frequent fatty stools.
Photo courtesy of Frank J. Accurso, MD
Importance of Early Diagnosis
74% are
diagnosed by 2
years of age
“On the basis of a
preponderance of
evidence, the health
benefits to children
with CF outweigh the
risk of harm and justify
CF.”
screening for CF.”
Newborn Screening….
Is an essential, preventive public
health program for early identification
of disorders that can lead to
catastrophic health problems.
The cost of these disorders, if left
untreated, is enormous, both in
human suffering and in financial terms.
Brief Review of the Texas Brief Review of the Texas
Newborn Screening Program Newborn Screening Program
• 2005 - NNSGRC review – external review of NBS program
• 1963 – Phenylketonuria (PKU) pilot
• June 2005 - House Bill 790 mandated expansion to ACMG
• 1965 – Mandated PKU screening recommended core panel of 29 disorders as funding allowed
• 1978 – Added Galactosemia & Homocystinuria screening • No funding for Cystic Fibrosis provided
• 1980 – Added Congenital Hypothyroidism screening, • May 2006: Cost effectiveness study complete – testing to be
Recommended second screen performed by DSHS Laboratory
• 1983 – Discontinued Homocystinuria screening, added • December 2006: 1st abnormal MS/MS results reported
Hemoglobinopathy screening, Required second screen • 19 new disorders
• 1989 – Added Congenital Adrenal Hyperplasia screening • January 2007: Added Biotinidase deficiency screening
• February 2007: New report implemented to provide results on all
• 1995 – Added second-tier DNA testing for hemoglobinopathies 27 disorders
• 2002 - Expanded NBS Task Force recommended the program • June 2007: No funding for Cystic Fibrosis NBS.
expand with MS/MS technology (add 4 disorders)
• 2003 – Legislation to expand program did not pass
• June 2009: Funding secured for CF NBS with IRT/IRT/DNA!
December 2009: Planned implementation of TX CF NBS!
Review: Texas NBS Program Cystic Fibrosis:
Overarching Assumptions
• 2008: Received ~796,000
specimens
– Specimens Assayed and
• IRT/IRT/DNA model
Reported: ~791,000
– ~ 4,800 unsatisfactory
specimens (~0.60%)
• DSHS workload estimates:
– Avg: 2,527 specimens/day
• FY10: 818,000 screens
• Linking of specimens - • FY11: 828,000 screens
overall success rate
– 2008: 84.8%
• Two screening tests for each baby
born in Texas
– 2009: 87.4% • Estimate 82-94 diagnosed cases annually
• 24 – 48 hours of age • Infants testing positive
• 1 – 2 weeks of age receive prompt confirmatory
testing.
Testing Algorithm (IRT/IRT/DNA) Cystic Fibrosis Newborn Screening Algorithm
1st Screen Blood Spot
1st Screen w/elevated IRT
& 2nd Screen not received
• Measure IRT levels on both 1st and 2nd screens Elevated IRT 1 month after birth
2nd Screen Blood Spot
• Elevated IRT levels on both screens triggers a DNA test
Normal IRT Normal IRT Elevated IRT
• Fail safe protocol:
• If 2nd screen not received within 30 days after Normal CF Screen CFTR Mutational Analysis
birth, reflex to DNA
DSHS Positive CF NBS
Elevated IRT Elevated IRT Elevated IRT
2 CFTR 1 CFTR 0 CFTR
mutations mutation mutation
Cystic Fibrosis Newborn Screening Algorithm Cystic Fibrosis Newborn Screening Algorithm
1st Screen Blood Spot 1st Screen Blood Spot
Normal IRT Elevated IRT “Indeterminate” Elevated IRT
Causes for elevated IRT: • Many unaffected infants 2nd Screen Blood Spot
have an elevated
•Perinatal asphyxia immunoreactive trypsinogen
(IRT) level on the first Normal IRT
•Septicemia
specimen.
•Trisomies (13, 18 & 21)
• The second screening Normal CF Screen
•Obstructive liver disease
specimen (collected after 7
•Biliary atresia days of age) is required to
determine if result is
•Necrotizing enterocolitis
significant.
(NEC)
•Intestinal perforation • Please repeat the newborn
screen.
•Hydronephrosis
DSHS Positive CF NBS
Cystic Fibrosis Newborn Screening Algorithm Elevated IRT Elevated IRT Elevated IRT
2 CFTR 1 CFTR 0 CFTR
mutations mutation mutation
1st Screen Blood Spot
1st Screen w/elevated IRT
& 2nd Screen not received
Elevated IRT 1 month after birth?
Abnormal Abnormal Inconclusive
2nd Screen Blood Spot
Two potential Cystic Fibrosis- One mutation, DF508, in the No further evaluation necessary
causing mutations, DF508 and Cystic Fibrosis Transmembrane unless clinically indicated.
R117H (7T/9T), in the Cystic Conductance Regulator (CFTR)
Normal IRT Elevated IRT Fibrosis Transmembrane gene was identified. Cystic Although there is a minimal risk
Conductance Regulator Fibrosis can not be ruled out due for Cystic Fibrosis (CF) in the
(CFTR) gene were identified. to a possibility of a second absence of detected mutations,
Normal CF Screen CFTR Mutational Analysis mutation which is not included in an elevated immunoreactive
Recommend referral for the 40-mutation panel. trypsinogen (IRT) result may be
confirmatory sweat testing and indicative of CF due to a
DSHS Positive CF NBS consider genetic counseling. Recommend referral for mutation not included in the 40-
confirmatory sweat testing and mutation panel.
Elevated IRT Elevated IRT Elevated IRT consider genetic counseling.
2 CFTR 1 CFTR 0 CFTR Recommend sweat testing and
mutations mutation mutation possible genetic evaluation only
if clinically indicated.
Example:
CFTR Mutation Panel Normal Screen Report
∆F508 R334W Q493X
∆I507 R347P 3905insT
G542X 711+1G>T V520F
G551D 1898+1G>A S549R (T>G)
W1282X 2184delA 394delTT
N1303K 1078delT E60X
R553X 3849+10kbC>T 3849+4A>G
621+1G>T 2789+5G>A R347H
R117H 3659delC S549R A>C
1717-1G>A 3120+1G>A Y1092X C>A
A455E S549N Y1092X C>G
R560T 3876delA Y122X
R1162X 2183AA>G F508C
G85E D1152H IVS8-5T/7T/9T
Example: Abnormal Screen Report
Abnormal Screen Report
Positive CF NBS:
What Now or Next? 115 CFF Accredited Care Centers plus 54 affiliate-care centers nationally
Texas (Pediatric)
DSHS case will be created for case management if: Cook Children's Medical Center Baylor College of Medicine/Texas Children's Hospital
Fort Worth, TX 76104 Houston, TX 77030
Director(s): Nancy N. Dambro, M.D., James C. Cunningham, M.D.
• 2 very elevated IRT levels detected Appointments: (682) 885-6299
Director(s): Christopher M. Oermann, M.D., Peter Hiatt, M.D.
Appointments: (832) 822-2778
CF NBS Contact: Elizabeth Musser, RN CF NBS Contact: Sally Mason, RN
• 2 elevated IRT results and one or two mutations on DNA analysis Email: Elizabeth.Musser@cookchildrens.org
Phone: (682) 885-6572
Email: skmason@texaschildrens.org
Phone: (832) 822-3933
OR
Texas Tech University Health Science Center Dell Children's Medical Center of Central Texas
Single elevated IRT and one or two mutations on DNA if only one Department of Pediatrics Austin, TX 78723
screen received Lubbock, Texas
Director: Adaobi Karu, MD
Director(s): Bennie McWilliams, M.D., Allan Frank, M.D.
Appointments: (512) 324-0137
Appointments: (806) 743-2244
CF NBS Contact: Nelda Garcia, RN
• Case will be handled similar to other newborn conditions: CF NBS Contact: Adaobi Karu, MD Email: NGarcia@seton.org
Email: Adaobi.Karu@ttuhsc.edu Phone: (512) 324-9999 (ext 86331)
Phone: (806) 743-2244
• Parent will receive a letter with notification of screen results
Children's Medical Center of Dallas (PEDIATRIC) Christus Santa Rosa Children's Hospital (PEDIATRIC)
• PCP will receive a mailer from laboratory with results Dallas, TX 75235 San Antonio, TX 78207
Director: Claude B. Prestidge, M.D.
• NBS Nurse will call PCP with results and FAX follow up info Appointments: (214) 456-2361
Director: Donna Beth Willey-Courand, M.D.
Appointments: (210) 704-2596
CF NBS Contact: Carolyn Cannon, MD CF NBS Contact: Michelle Stress, RN
• CF center M.D. will be notified of child referred for sweat test Email: Carolyn.Cannon@utsouthwestern.edu Email: Michelle.Stress@christushealth.net
Phone: (214) 648-8709 Phone: (210) 704-2338
Sweat Test Cystic Fibrosis Newborn Screening Algorithm
1st Screen Blood Spot
• Gold standard 1st Screen w/elevated IRT
& 2nd Screen not received
– Pilocarpine Iontophoresis Elevated IRT 1 month after birth
– Collection Methods: 2nd Screen Blood Spot
• Gibson Cook Method
– Collect sweat on dry gauze with direct Normal IRT Normal IRT Elevated IRT
measurement of chloride concentration
– Need 75 mg of sweat
Normal CF Screen CFTR Mutational Analysis
• Macroduct Coil Collection System with
direct measurement of chloride
concentration
DSHS Positive CF NBS
– Need 50 mcg of sweat
Elevated IRT Elevated IRT Elevated IRT
2 CFTR 1 CFTR 0 CFTR
mutations mutation mutation
DSHS Positive CF NBS DSHS Positive CF NBS
Elevated IRT Elevated IRT Elevated IRT Elevated IRT Elevated IRT Elevated IRT
2 CFTR mutations 1 CFTR mutation 0 CFTR mutation 2 CFTR mutations 1 CFTR mutation 0 CFTR mutation
CF Center for sweat test CF Center for sweat test
Sweat chloride Sweat chloride Sweat chloride Sweat chloride
> 60 mEq/L 60 mEq/L Sweat chloride 30 but 60 mEq/L Sweat chloride 30 but 60 mEq/L
Sweat chloride
> 30 but < 60 Eq/L
Sweat chloride
< 30 mEq/L • Weight and nutrition assessed at each visit
(diagnostic for CF) (equivocal results) (normal)
• Annual labs
2 CFTR mutations 2 CFTR mutations 1 CFTR mutation – blood work
– CXR
– Liver scans
– Bone scan over age 12
Cystic Fibrosis CF Carrier Normal
– Glucose tolerance test over age 14
Genetic Counseling Genetic Counseling
CF Center care
Pulmonary Health Strategies CF Care Center: Individualized Care
Impaired
Bronchial
Mucociliary
Obstruction
Clearance
Infection Inflammation
Recognize Multi-System Impact of CF Common Comorbid Conditions in Patients with CF
over the Lifespan
35
30
25
Percent
20
15
10
5
0
<6 6 to 10 11 to 17 18 to 24 25 to 34 35 to 44 45+
Age (years)
Bone Disease Diabetes (CFRD) Depression
Cystic Fibrosis Foundation Patient Registry, 2007
2008 RESEARCH PRE- PHASE
CLINICAL
PHASE
1
PHASE
2
TO
3 PATIENTS
Gene Therapy
2004 CFTR Modulation
Restore Airway Surface Liquid
Mucus Alteration
Anti-Inflammatory
Anti-Infective
Transplantation
Nutrition
“Adding Tomorrows Every Day”
John Saito, MD, FAAP, FCCP
Children’
Cook Children’s Medical Center
Fort Worth, Texas
John.Saito@cookchildrens.org
www.ARTinMEDICINE.com
www.ARTinMEDICINE.com
Source: CF Foundation