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Advances in Newborn Screening David Kronn, MD, FACMG, FAAP

Genetics Visiting Professor (GVP) Grand Rounds Presented by: AAP Chapter 3 and the Lower Hudson Valley Perinatal Network (LHVPN). Advances in Newborn Screening David Kronn, MD, FACMG, FAAP Director, Inherited Metabolic Disease Center

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Advances in Newborn Screening David Kronn, MD, FACMG, FAAP

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  1. Genetics Visiting Professor (GVP) Grand RoundsPresented by: AAP Chapter 3 and the Lower Hudson Valley Perinatal Network (LHVPN) Advances in Newborn Screening David Kronn, MD, FACMG, FAAP Director, Inherited Metabolic Disease Center Maria Fareri Children’s Hospital at Westchester Medical Center Associate Professor of Pediatrics New York Medical College

  2. Genetics Visiting Professorship • The Genetics Visiting Professorship is a competitive award of the American Academy of Pediatrics (AAP) Newborn Screening Program, and funded through a joint public/private partnership between the Maternal and Child Health Bureau/Health Resources and Services Administration, the National Coordinating Center for the Regional Genetics and Newborn Screening Service Collaboratives, housed at the American College of Medical Genetics, and the AAP.

  3. GVP: Partnership Between AAP and LHVPN Lower Hudson Valley Perinatal Network (LHVPN) has the the goal of making sure all babies are born healthy. Together we work to advocate for and educate consumers and professionals about maternal, child and family health issues impacting the region. The goals of the GVP program are: • Updates on what new genetic diseases have been added to the newborn screen • Managing abnormal results (disease and carrier states) from the newborn screen • Review of the primary care provider's role in caring for newborns with genetic diseases diagnosed by newborn screen • Discussing newer genetic diagnostic techniques such as microarray analysis

  4. Summary Questions • What is Newborn Screening? • What role has New York played in the development of Newborn Screening? • How do we choose which diseases to screen? • What are the demographics of Newborn Screening in New York State? • What have been the consequences of expanding Newborn Screening? • What can we expect form Newborn Screening in the future? • What is tandem mass spectroscopy?

  5. What is Newborn Screening?

  6. “The goal of newborn screening is early detection of children at increased risk for selected metabolic or genetic diseases so that medical treatment can be promptly initiated to avert metabolic crises and prevent irreversible neurological and developmental sequelae.” Newborn Screening in New York - A Guide for Health Professionals 1991

  7. Rationale for Treatment of Genetic Disease Newborn Screening Early Diagnosis Intervention Prior to Onset of Symptoms Prevention of Disease Progression

  8. Phenylketonuria (PKU) • Frequency about 1 in 10,000 births in Caucasian population • Phenylalanine is neurotoxic at high levels • Defect in enzyme phenylalanine hydroxylase • 1 to 2 % of cases due to defect in dihydropteridine reductase (DHPR) or in the synthesis of biopterin • Treatment is for life • Maternal PKU effects

  9. Time Line for Specimen Collection Day of Life 1 2 3 4 5 24 48 72 96 Age (hours) Birth Specimen Quality A B C C C

  10. Newborn Screening: Early Discharge Missing the diagnosis Abnormal Metabolite Level Threshold Level Time

  11. Algorithim for Newborn Screening Newborn Screening Results Screen Positive Referral to Specialty Center Borderline Screen Negative Case Complete Repeat Specimen Negative Positive Specific evaluation for confirmation of diagnosis Positive Negative

  12. What role has New York played in the development of Newborn Screening?

  13. Dr. Robert Guthrie (1916-1995)

  14. History of Newborn Screening in New York State • 1930’s George Jervis at Letchworth Village State School in Thiells, NY identified 50 clients with metal retardation attributed to PKU • 1963 Robert Guthrie, microbiologist-pediatrician at State University of New York, Buffalo, devised simple inexpensive which allowed screening for PKU • 1964 Robert Guthrie coordinated a 29 state pilot study of screening in 400,000 newborns for PKU, proved so successful that many states instituted newborn screening immeadiately • 1965 New York State law for newborn screening, Public Health Law 2500a went into effect, mandating that every newborn be screened for PKU • 2002 Introduction of MS/MS technology for the testing of PKU, MSUD, Homocystinuria, and MCAD Deficiency • 2006 Addition of Krabbe Disease to the panel

  15. How do we choose which diseases to screen?

  16. The Cardinal Principles of Screening Some of the basic criteria for determining which inherited disorders for newborn screening include: • The disorder has a relatively high incidence so that the cost per diagnosed individual is reasonable • An effective and not overly expensive treatment is available • A relatively inexpensive screening test is available that is suitable for high volume testing (preferably automatable) • The screening test has a very high sensitivity ( i.e. a very low rate of false negatives) and high specificity ( i.e. low rate of false positives which require expensive follow-up)

  17. Criteria for Newborn Screening • Disorder produces irreversible damage before onset of symptoms • Treatment is effective if begun early • Natural history of disorder is known

  18. What are the Demographics of Newborn Screening?

  19. New York State Newborn Screening Program 1965-2007

  20. What have been the consequences of expanding Newborn Screening?

  21. Positive Consequences • Early detection of potentially life threatening conditions • Early treatment and prevention of sequelae

  22. Negative Consequences • High False Positive Rates • Impact on families • Impact on health system • Uncovering variant conditions with unclear pathogenesis • Detection of carriers

  23. Potential Impact of False Positives • USA 4,100,000 births per year • 1:2,400 confirmed diagnoses • 10 - 20 False Positives per diagnosis • 25,000 – 50,000 False Positives • Lets look at New York State 2007 Data • Review 2007 report

  24. Why Parents May Be Vulnerable • Peak health worries occur in the 25-34 age group • In general young people worry more than older people • Younger people more active and problem focused • Older people more passive and emotion focused Lindsay et al., Worry over the lifespan. Psychological Medicine 2006; 1-9

  25. A Few Examples of Negative Consequences We increasingly need to be aware of the complexities of testing and to communicate this sensitively to our patients • “It was scary and when I found out my daughter was fine I felt like we’d gone through a lot for nothing.” • “I was upset as they (the physicians) were elusive about why my child had to return for a repeat test.” • “The pediatrician said that a blood test was needed, but she didn’t know what it was for” • “We were told ‘no news is good news’. They never called back with the results”

  26. Medium Chain Acyl-CoA Dehydrogenase Deficiency

  27. Medium Chain Acyl CoA Dehydrogenase Deficiency • Most common FAOD, incidence up 1 in 10,000 • Exclusively hepatic presentation - most frequently seen as • hypoketotic hypoglycemia provoked by fasting • May be a history of sibling death • Affected individuals usually normal until an episode occurs • Newborn screening by ms/ms with elevated octanoylcarntine • Specific abnormalities seen on urine organic acid analysis, • acylcarnitine, plasma free fatty acid and acylglycine analysis • MCAD gene has been cloned to chromosome 1p31. A single mutation at nucleotide 985, A to G accounts for 90% of disease carrying alleles. • Treatment revolves around prevention of fasting, the use • of carnitine remains controversial

  28. MCADD Screening Method: Octanoylcarnitine level by Tandem Mass Spectrometry MCAD Deficiency: Octanoylcarntine Peak

  29. Newborn Screening Consequences • Detection of Unaffected Carriers • ACMG recommendation on carrier screening advises waiting to test until individuals can consent themselves for testing, provided the result has no bearing on health to that point. • No clear policy on how to deal with these patients • A major concern for Cystic Fibrosis • Look at 2007 report again!

  30. Cautionary Tales!

  31. Expanded Screening Problems • Overall we seem to be dealing with lots of false positives • Are SCAD and 3-MCC Diseases? • Low C0 levels from the NICU

  32. Newborn Screening Consequences – Additional Concerns • Patients born in adjoining states may not have had access to the same expanded screening • Siblings born in different states and different countries • Siblings born before and after the expansion of newborn screening • The demographic on the newborn screening card can sometimes be incorrect and lead to delays in locating patients for follow up testing

  33. What can we expect form Newborn Screening in the future?

  34. Krabbe Disease

  35. Infantile Krabbe Disease • Globoid cell leukodystrophy • Autosomal recessive disorder • Incidence ~1/100,000 • Enzyme defect lysosomal galactocerebrosidase • Inability to degrade glycolipids found almost exclusively in myelin • Clinically presents with dystonia (lead-pipe) rigidity of the limbs and abnormal posturing) from about 6 months • Patients have irritability, poor feeding, motor regression and seizures. • MRI: White matter changes and calcification particularly affecting the basal ganglia • Death usually by two years of age.

  36. Newborn Screening for Krabbe Disease • Measurement of artificial product by ESI-MS/MS • Diagnosis by enzyme analysis and DNA analysis • Additional studies to confirm diagnosis • Brain MRI, CSF Protein, EEG, Neuro Eval. • Treatment by Umbilical-Cord Blood Transplantation • Long-term follow-up required

  37. Krabbe Disease Screening - Concerns • Screening • What is the false positive rate? It appears high • Does the burden of disease warrant screening? • Diagnosis • Can we differentiate between infantile and adult onset forms of the disease? • Will false positives who turn out to be carriers require genetic counseling and family studies? • Treatment • Can a HLA match be found for every patient screened positive? • What is the longterm outcome of treatment? • Who will pay?

  38. Krabbe Disease Update as of December 2008 • Over 80 referrals for low enzyme activity • Majority of patients have low levels on repeat but above that expected for affected patients majority due to polymorphisms in the gene. • Two patients so far have been identified with infantile Krabbe Disease and have been transplanted, one patient died of transplant complication • Four other patients have enzyme assays suggesting juvenile or adult onset disease, they are all stable at this point

  39. Future Newborn Screening Disorders – the latest new kids on the block • Lysosomal Storage Disorders • Enzyme Replacement Therapy and Bone Marrow/ Umbilical Cord Cell Transplants more readily available. • Peroxisomal Disorders • Adrenoleukodystrophy. Studies have shown the benefit of Lorenzo’s Oil in presymptomatic individuals • SCID • Clear benefit from transplantation

  40. What is Tandem Mass Spectrometry?

  41. What does MS/MS offer? • Increased specificity, decreased false positives • One test many diseases • Many diseases do not meet the criteria for Newborn screening,but public opinion and availability of technology warrant offering testing for the larger group of diseases.

  42. Mass Spectrometry 101

  43. TMS Selective mass measurement Collision cell Source Analyzer Fragmentation in inert gas chamber First Mass Analyzer Second Mass Analyzer Separation by molecular weight and charge - m/z Note: Acylcarnitine analysis by loss of butyl ester, common 85mw fragment Amino acid analysis by loss of neutral molecule 102mw Different scan function can be produced in series

  44. Mass spectrometry +COH +CH3 CH3COCH3 CH3+COCH3 CH3C+OCH3 +COCH3 Ionization & Adsorption of Excess Energy Fragmentation (Dissociation) Detection Mass Analysis Sample Inlet

  45. Fragmentation of butylated Phenylalanine

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