1. Update on Newborn Screening for Cystic Fibrosis
Jacquelyn Zirbes, DNP, RN, CNP, CCRC
Stanford University Cystic Fibrosis Center
Lucile Packard Children’s Hospital

2. Discovery of the ∆F508 CFTR Mutation
Research teams led by Lap-Chee Tsui, Jack Riordan,
and Francis Collins
…the CF gene was discovered in 1989 and the principal mutation, the F508 was identified. The product of the CF gene is the CFTR protein which is a chloride channel. The clinical manifestations of CF are primarily attributable to defective functioning of this chloride channel. 2

3. Newborn Screening Definition *
Population-based public health program applying preventive medicine in defined regions to reduce infant morbidity and mortality from certain biochemical and genetic disorders by using presymptomatic detection/diagnosis with dried blood specimens from newborns analyzed in central laboratories employing automated procedures linked to clinical follow-up systems.
So, what is newborn screening? Allen and Farrell describe it as a population-based public health program using PREVENTION with the goal of reducing infant morbidity and mortality. Through newborn screening test, we can identify biochemical and genetic disorders before the infant becomes symptomatic. Using dried blood spot specimens that are linked to central labs, procedures are activated to clinical follow-up systems.
Newborn metabolic screening includes screening for organic acids, fatty acids, oxidation, organic, disorders, endocrine, hemoglobinopathies, and other disorders including cystic fibrosis. My understanding is the State of Calf will be adding this panel as of June of this year.
Allen and Farrell (1996). Adv Pediatrics 43:
Allen and Farrell (1996). Adv Pediatrics 43:

4. Principles of Achieving Better Outcomes Through Newborn Screening
Screening/Follow-up Diagnosis
Effective Therapy
Death
Birth
Biologic
Onset
Life Threatening
Or Irreversible
Disease
Symptomatic
Onset
Our ability to screen for disease is expanding. This slide illustrates a timeline that by utilizing newborn screening, we are able to intervene during the preclinical stage, before symptomatic onset and prevent or arrest life threatening or irreversible disease. Technology is available with tandem mass spectrometry to measure metabolites on newborn blood. This is the stage where your NBS can have a impact on public health outcomes for these families
Preclinical Stage
Time/Event

7. Diagnosis Through Newborn Screening
Guthrie Card
California NB screening for over 50 disorders- includes CF as of July The screening profile includes 46 known genetic mutations for CF. Use next slide to illustrate algorith.
This ~0.4 ml dried blood specimen supports numerous screening tests!

8. Primary Care Provider CF Center Dedicated Line NBS Coordinator Family
NBS State Program:
Positive Screen
Primary Care Provider
CF Center
Dedicated Line
NBS Coordinator
Family

9. California 4-Step CF NBS Model
Immunoreactive Trypsinogen assay (cut-off = 1.6%; projected sensitivity= 95.7%)
DNA analysis with a panel of 40 CFTR mutations (15/23 ACMG* mutations + “minority” alleles)
DNA scanning  sequencing by Ambry
Sweat test when 2 or more mutations detected

10. California 4-Step Method’s Goals
Use initial dried blood specimen only
Focus on “severe” cases of cystic fibrosis
Identify at least 90% of Hispanic, White, and Black cases
Reduce burden of false positives & negatives, sweat tests, and costs
Achieve efficient reporting of NBS test results
Follow-up and diagnosis of positive screens at CF Centers

11. (exception: DF508 /DF508 = CF)
SCREENING ≠ DIAGNOSIS
(exception: DF508 /DF508 = CF) 11

12. Definition of “Screening for Early Detection of Disease”
“The screening procedure itself does not diagnose illness.”
“Those who test positive are sent for further evaluation by a subsequent diagnostic test or procedure to determine whether they do in fact have the disease.”
Hennekens and Buring, Epidemiology in Medicine, p327 12

13. California Minimum Guidelines
1. Preparation for Sweat Chloride Test
2. Sweat Chloride Test
3. Laboratory testing at first CF Center visit
4. Family Studies
5. Interpretation of Sweat Chloride Test Results

17. Throat Culture Results

19. Updated California Results
210 infants identified
13 CF Centers
27 LPCH
ΔF508/ ΔF508 1
First 7 months
ΔF508/other 18
other/other 8

21. Genotype-Phenotype Relationships*
General Principle: genotype determines phenotype
(e.g., pancreatic insufficiency vs sufficiency in CF)
But, gene modifiers and extrinsic factors contribute also
In metabolic disorders such as PKU, mild (non-classical) cases can occur
In CF, genotype alone does not determine the pulmonary phenotype
* Zielenski J and Tsui LC, Ann Rev Genet 1995; 29:

22. CA CF NBS Collaborative Network
California Genetic Disease Screening Program
Children’s Hospital of Central California
Children’s Hospital of Los Angeles
Children's Hospital and Research Center at Oakland
Kaiser Permanente Southern California
Loma Linda University Medical Center
Miller Children's at Long Beach Memorial Medical Center
Stanford University
Sutter Sacramento Medical Center
University of California San Diego
University of California San Francisco
Ventura County Medical Center

23. Advisory Board Frank Accurso, MD University of Colorado
Phil Farrell, MD, PhD University of Wisconsin
Paul Quinton, PhD University of California San Diego
Jeff Wine, PhD Stanford University

24. Specific Aims
In a well defined cohort of newborns with fully identified CFTR mutations determine:
1. The feasibility of applying a uniform infant preparation protocol for sweat testing that includes salt supplementation and adequate fluid intake guidelines
2. The genotypic determinants of sweat chloride concentration and its longitudinal changes.
3. The effect of fluid and electrolyte balance on sweat chloride results

25. Study Outcome Measures
-Primary Outcome Measure
Sweat chloride concentration at diagnosis.
We hypothesize that under the baseline conditions created by the preparation protocol sweat chloride will unequivocally discriminate between varying levels of CFTR dysfunction.

26. Study Outcome Measures
Secondary Outcomes
Serum aldosterone, urinary and serum electrolytes.
Serum IRT
Longitudinal changes in sweat chloride
Longitudinal changes in clinical parameters during the first 2 years of life to gain

27. Study entry criteria Inclusion criteria:
1) Positive California CF newborn screening result (2 CFTR mutations identified).
2) Post-menstrual age ≥ 36 weeks
3) Age at time of first sweat test ≥ 2 weeks old and ≤ 16 weeks old
4) Weight at time of sweat test ≥ 2 Kg
Exclusion criteria:
1) NICU Hospitalization at the time of diagnosis.
2) Requiring IV fluids and/or TPN at the time of test.
3) Diagnosis of hypothyroidism or other endocrinologic/metabolic abnormality.
4) Presence of any other active medical condition (e.g. congenital heart, liver, or renal disease) that in the opinion of the CF Center would interfere with reliable sweat testing.

28. Study Protocol Study participation for approximately 2 years
Patients will be evaluated 5 times over the 2 year period
Family will receive salt supplementation kit (salt packets, instructions and educational material) in anticipation of study visit

29. Study Procedures VISIT Pre-Visit Visit 1 Visit 2 Visit 3 Visit 4
Time
Phone
Result
Initial Diagnostic
1 month post visit 1
6 (± 1) mos. old
12 (± 1) mos. old
24 (± 1) mos. old
Salt Kit X
Sweat
Serum
Urine
Clinical
Measures
Micro
Stool

30. Care of the CF Infant Diagnosed after Newborn Screening
CF Foundation Consensus Guidelines are still evolving
Need to develop a collaborative care model with PCP-subspecialist partnership
An evidence based medicine strategy is very difficult to develop
Thus, prudent principles of Dx → Rx based on need should be followed
Set high standards such as > 50th percentile growth and normal PFT’s
But, avoid overly aggressive clinical management (primum non nocere) 30

31. Early Diagnosis & Treatment
Goals of CF
Early Diagnosis & Treatment
Initiate CF center care in newborns
Provide genetic counseling
Prevent severe malnutrition
• Vitamin E deficiency (hemolytic anemia)
• Vitamin A deficiency
• Essential fatty acid deficiency
• Protein energy malnutrition*
• Growth failure
Prevent hyponatremia/hypochloremia
• Salt loss in sweat*
• Associated with breast feeding
Prevent early progression of lung disease
• Recurrent bacterial infections
• Obstructive pulmonary disease
• Atelectasis with mucus plugs
* Potentially fatal
[highlight points in pink]
Slide 16 or 17 says the same thing Which slide? 31

32. The GI/Nutrition Rationale for NBS
1. CF patients are generally well nourished at birth
2. PI will develop in ~90% of patients by ~1 year
3. Severe malnutrition will develop in ~50% untreated
4. PI can be anticipated and malnutrition prevented
5. Long term benefits of normal nutrition are significant 32

33. The Pulmonary Rationale for NBS
1. The CF lung is normal at birth, but not for long.
2. Lung disease often develops as early as 2 months.
3. Pseudomonas aeruginosa (PA) colonization may occur in ~1/3 of undiagnosed patients.
4. Transformation from PA to mucoid PA is the greatest long term risk for children. 33

34. The 21st Century is a New Era for Children with CF
• An established trend of early diagnosis through NBS
• A paradigm shift in therapeutic strategy from the 3 I’s to the 3 P’s
• No longer dominated by intervention in individuals with illnesses
• But prevention in presymptomatic patients
– Prevention of early deaths
– Prevention of salt depletion
– Prevention of malnutrition and growth failure
– Prevention of “cross-infection”
– Prevention of chronic PA and early mPA
– Prevention of hospitalizations
– Prevention (eventually) of lung disease 34

35. Summary of Advantages of CF Newborn Screening
Avoid diagnostic quest
Early, specific and proper care
Proactive strategy of care
Prevention
Improved quality of life
Improved parental learning
Reduce costs
Prevent malnutrition and micronutrient deficiencies
Reduce risk of cognitive dysfunction
With the use of genomics in newborn screening, the CF center team can use the information to direct clinical care and avoid the hunt for a diagnosis. With the implementation of therapy, early intervention can prevent the occurrence or progression of illness/disease. With increased public awareness through education and delivery of direct clinical care, we can impact public health outcomes. This provides an opportunity to demonstrate how a multidisciplinary team can influence outcomes with newborn screening in cystic fibrosis.

36. The Stanford Cystic Fibrosis Center at Lucile Packard Children’s Hospital
Individual Treatment Plan
Collaborative Care
Interdisciplinary Team
Standards of CF Care
Family Centered Care
Emphasis on Family and Primary Provider Education
Research