newborn screening greg enns, mb, chb, faap professor of pediatrics

NEWBORN SCREENING

Greg Enns, MB, ChB, FAAPProfessor of Pediatrics

Director, Biochemical Genetics ProgramLucile Packard Children’s Hospital

October 22, 2015

Newborn Screening Goal

The early detection of conditions for which early and timely interventions can lead to the elimination or reduction of associated mortality, morbidity and disabilities

2American Academy of Pediatrics Report Pediatrics 106:389, 2000

When is screening a good idea Condition

◦ Of medical importance, significant morbidity and/or mortality◦ Natural history well understood

Screening Test◦ Safe, precise, validated test

Treatment◦ Effective treatment is available◦ It is beneficial to start treatment early, before the onset of symptoms

Cost-benefit Analysis◦ The overall expense of the screening program is acceptable given the expected

benefit to patients and families The social context

◦ The program, including testing, counseling and treatment is acceptable to the society in which it is being carried out

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PHENYLKETONURIA (PKU)

Untreated PKUMental retardationDecreased deep tendon reflexes and spasticitySeizuresAcquired microcephalyPale pigmentation Dry skinMousy odor (phenylacetic acid in urine and sweat)

PKU Newborn Screening Outcome

PKU Clinical ManagementRegular appointments with the Metabolic

“team” physician, nutritionist, genetic counselor, nurse, social worker

Regular blood phenylalanine levels◦Once a week to once a month for the first 12

month (average once a week)◦Once a month to every 3 months throughout

childhood

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History of Newborn Screening in California

• 1966 - PKU

• 1980 - Hypothyroidism, Galactosemia

• 1990 - Sickle Cell Disease, other Hemoglobinopathies

• 2002 - 2003 - MS/MS Pilot Project• 2005 - Expanded MS/MS screening

Current California Newborn Screening

550,000 Newborns per year

(~1/8 of neonates born annually in USA)

>99% screened

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THE “HEELSTICK TEST”

Courtesey Dr. Ed McCabe

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Filter Card Punch

Courtesey Dr. John Sherwin

Tandem Mass Spectrometry (MS/MS) Target Analytes for Newborn Screening

• Amino acids

• Acylcarnitines– Intermediates of:

• Organic acids• Fatty acids

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Acylcarnitine Profile

• Plasma/serum• >30 compounds

– fatty acids– organic acids

• Quick prep and run

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Acylcarnitines

Acyl group of varying chain length attached to carnitine

Acyl groups derived from organic acid metabolism and fatty acid oxidation

Examples include:◦Octanoylcarnitine (C8-acylcarnitine)◦Propionylcarnitine (C3-acylcarnitine)

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What is an acylcarnitine?

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(CH3)3N-CH2-CH-CH2-COO-+

=ORC- O

=

Hexanoylcarnitine R = CH3(CH2)3CH2-

O

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+Precursor (85.0): 28 MCA scans from Sample 6 (H38870 Asa-Nunies, W) of Data081004.wiff Max. 1.5e6 cps.

200 220 240 260 280 300 320 340 360 380 400 420 440 460 480 500m/z, amu

0.0

1.0e5

2.0e5

3.0e5

4.0e5

5.0e5

6.0e5

7.0e5

8.0e5

9.0e5

1.0e6

1.1e6

1.2e6

1.3e6

1.4e6

1.5e6

Inte

ns

ity, c

ps

218.5

260.5

227.5 459.7

263.5 311.6 437.6291.5221.3 375.6

347.6277.4

204.5 288.4 370.4 461.5327.4 342.5 482.4400.5 426.7237.4

C2-d3

C8-d3C10-d3

C16-d3

C2

C0-d9

C5-d9

C3-d3

C4-d3

C0

C14-d9

Normal Acylcarnitine

Profile

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MCAD Deficiency Acylcarnitine

ProfileOctanoylcarnitine

Medium-chain Acyl-CoA Dehydrogenase (MCAD) Deficiency

~1/10,000 in CaucasiansSudden infant death syndromeReye-like syndromeEpisodic illness 6-24 months as a consequence of

catabolismMay have myopathy, cardiomyopathyHypoketotic hypoglycemia

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FATTY ACID METABOLISM

• The primary energy source for:– Cardiac muscle– Skeletal muscle

• A necessary energy source during:– Fasting – Stress

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7.09e3 cps+Precursor (85): Expt. 3, 0.73 min (26 scans) from 070902-10

% % MultiView -- © 1996, SCIEX, a division of MDS Health Group.% % Original concept:% Dr. Ron Bonner% Dr. Lyle Burton% % Development:% Dr. Lyle Burton% Yves Legault% Shengping Ma% % With the help of:% Dr. Victoria Barclay% Scott Champ% Rob McDermid%

300 350 400 450 500m/z, amu

20

40

60

80

% In

tens

ity

4.14e3 cps+Precursor (85): Expt. 3, 0.73 min (26 scans) from 070902-12

% % MultiView -- © 1996, SCIEX, a division of MDS Health Group.% % Original concept:% Dr. Ron Bonner% Dr. Lyle Burton% % Development:% Dr. Lyle Burton% Yves Legault% Shengping Ma% % With the help of:% Dr. Victoria Barclay% Scott Champ% Rob McDermid%

300 350 400 450 500m/z, amu

20

40

60

80

% In

tens

ity

Retrospective analysisof original NBS sample

Control

LCHAD

Long-chain 3-hydroxyacyl-CoA dehydrogenase (LCHAD) deficiency

Acylcarnitines (µM) in Original NBS Cards of LCHAD Deficient Patients

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m/z, amu

ControlC18:1

5000

m/z, amu

cps

5000

Sample 1

C18:1C16-OH C18-OH

m/z, amu

cps

Sample 2

C18:1

C16-OHC18-OH

5000

m/z, amu

cps

Sample 3C18:1

C16-OH

C18-OH

5000

m/z, amu

cps

Sample 4C18:1

C16-OH

C18-OH

5000

m/z, amu

cps

Sample 5

C18:1

C16-OHC18-OH

5000

m/z, amu

cps

Sample 6C18:1C16-OH

C18-OH

5000

m/z, amu

cps

Sample 7C18:1

C16-OH

C18-OH

5000

m/z, amu

cps

Sample 8C18:1

C16-OHC18-OH

5000

m/z, amu

cps

Sample 9C18:1

C16-OH

C18-OH

5000

m/z, amu

cps

Sample 10C18:1

C16-OH C18-OH

5000

cps

Control

C18:1

5000

m/z, amu

cps

DEAD

DEAD

DEAD

DEAD

DEAD

DEAD

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Newborns in California will soon get tested for more than 30 genetic illnesses that lead to serious health and developmental problems, a major increase in screening that will shore up the state's outdated protections for new babies.Gov. Arnold Schwarzenegger has already approved money for the new screening and is expected to sign the law finalizing it within the next two weeks. Most other states offer more newborn screening than California, which currently tests for only four.

August 4, 2004, Page 1A, San Jose Mercury News (CA)

STATE TO EXPAND TESTING OF NEWBORNS FOR GENETIC ILLS

Communication in Newborn Screening

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Primary Care Provider

Private Sector Laboratories

Family

Central LaboratorySpecialists:

Biochemical GeneticistEndocrinologistHematologist

Area Service Center

10-19 Disorders

U.S. Newborn Screening

Conditions Required – Sept, 2007

30-39 Disorders 40-49 Disorders 50+ Disorders

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43

44 45

50

48

35

46

50

50

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4147

20-29 Disorders

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37

30

14

3312

29

DC

51 1331

16

45

34

37

33

36

3030

‘Core’ 29 (21)

50

41

48

31

46

33 45

48

52

50

31

34

54 49

31

5049

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31

31

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Courtesey of Dr. Brad Therrell

genes-r-us

28http://genes-r-us.uthscsa.edu

29http://www.hrsa.gov/advisorycommittees/mchbadvisory/heritabledisorders/

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32www.cdph.ca.gov

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MS/MS Newborn Screening

A normal screening result does not exclude metabolic disease

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Optimal Path to Diagnosis

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• Metabolite or enzyme assay diagnostic testing

• DNA testing

PositiveNBS

UrgentReferral

Definitive Diagnosis

• To a geneticist or metabolic specialist

SUMMARY• Newborn screening does not detect everyone• Appropriate labs & investigations are needed to obtain final

diagnosis• A Uniform Screening Panel of 31 core disorders and 26

secondary disorders recommended by the DACHDNC has led to states testing for a similar number of disorders

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