الرحمن الله بسمالرحيم

Newborn Newborn ScreeningScreening

ByDr: Eman Mohamed Habib

• Is a public health program designed to screen infants

shortly after birth for a list of conditions that are

treatable, but not clinically evident in the newborn

period.

• Some of the conditions are only detectable after

irreversible damage has been done

• In some cases sudden death is the first manifestation of

the disease

Neonatal screeningNeonatal screening

Second screen strongly recommended

between 7 and 14 days of age2

3Third screen recommended for

sick and premature infants

Washington State law requires that every newborn be

tested within five days of age1

Who is screened?Who is screened?

• Most babies with metabolic disorder look normal at birth.

• By the appearance of signs and symptoms, irreversible

consequences are already present.

• So screening is essential as it allows

early intervention and prevention

of irreversible damage.

Why do newborn screening?Why do newborn screening?

1

Important condition

2

Acceptable treatment available

3

Facilities for

diagnosis and

treatment

4

Difficult to recognize

early

5

Suitable screening

test

Criteria for Newborn ScreeningCriteria for Newborn Screening

6

Natural history known

Cost-effective to diagnose and treat

7

Wilson & Jungner, 1968

Sample coleection

Result reportin

g

Testing workup

TECHNIQUETECHNIQUE

• Using the heel prick method, a

few drops of blood are taken from

the baby’s heel

• Blotted on a special absorbent

filter card

• Blood is dried for 4 hours and

sent to the Newborn Screening

Center

SAMPLE COLEECTIONSAMPLE COLEECTION

The filter paper is often attached to a form containing required information

about the infant and parents. This includes:

•Date and time of birth.

•Date and time of sample collection.

•The infant's weight and gestational age.

•Information about whether the baby has had a blood transfusion

•Any additional nutrition the baby may have received (TPN).

TESTING WORK UP

Compounds analyzed are amino acids

and acylcarnitines

• Amino acids – to identify PKU,

MSUD, homocystinuria

• Acylcarnitine – carnitine (vehicle) +

fatty acid for identification of

organic acidurias and fatty acid

oxidation disorders

Tandem Mass Spectrometer (MS/MS)Tandem Mass Spectrometer (MS/MS)

MS/MS Plasma Amino AcidsMS/MS Plasma Amino Acids

3. Enzyme assays are used to screen for

galactosemia and biotinidase deficiency

4.Immunoassays measure thyroid hormones for the diagnosis of congenital

hypothyroidism and 17-hydroxyprogesterone for the diagnosis of

congenital adrenal hyperplasia.

5. Molecular techniques are used for the

diagnosis of cystic fibrosis and severe

combined immunodeficiency.

B. bedside testing for hearing loss using evoked auditory potentials and congenital heart defects using pulse oximetry.

Results ReportingResults Reporting

• Immediately reported by phone and fax to baby’s

physician/nurse

• Phone calls made by genetic counselors and/or

clinicians who are familiar with the disorders

together with the pediatrician and the primary heath

care provider for immediate assessment and early

intervention.

The conditions included in newborn screening programs

around the world vary greatly, based on

Legal requirements

Prevalence of certain diseases within a population

political pressure and availability of resources for both testing

and follow-up of identified patients.

Which disorders should be identified?Which disorders should be identified?

2002 Maternal and Child Health Bureau commissioned ACMG

Recommend a core panel to create uniform NBS across all

states through scoring system.

Which disorders should be identified?Which disorders should be identified?

Incidence of condition

Sign & Symptoms clinically identifiable in the first 48 hours

Burden of disease (natural Hx if untreated)

Does a sensitive AND specific screening test currently exist

Test characteristics ( Yes= apply score; no = zero)

Availability of treatment

Cost of treatment

Potential efficacy of existing treatment

Benefits of early intervention (individual outcome)

Benefits of early identification (family & society)

Benefits diagnosis and treatment prevent mortality

Availability of diagnostic confirmation

Acute management

Simplicity of therapy

11 Amino acid disordersAmino acid disorders 22Fatty acid oxidation disordersFatty acid oxidation disorders

33 EndocrinopathiesEndocrinopathies 44HemoglobinopathiesHemoglobinopathies

55 Organic acidemiasOrganic acidemias 66Cystic fibrosisCystic fibrosis

77 Urea cycle disordersUrea cycle disorders 88Hearing lossHearing loss

99 Congenital heart defectsCongenital heart defects 1010Severe combined immunodeficiency

Severe combined immunodeficiency

1111 Other conditionsOther conditions

Target DisordersTarget Disorders

Amino Acid DisordersAmino Acid Disorders

• PKU: severe, permanent ID• MSUD: ID, hallucinations, ataxia• HCY: connective tissue damage (joints,

heart), ID, psychiatric disturbances• ASA: brittle hair, liver disease ID• TYR I: acute or chronic liver disease,

liver cancer, neurologic pain crises• Diagnosed by plasma amino acids,

urine amino acids, and/or urine organic

acids .

PKUPKU

Phenylalanine -------------------//----------------------- Tyrosine

(substrate) phenylalanine hydroxylase (product)

Disorder of phenylalanine hydroxylation leading to

accumulation of this amino acid.

Patients have progressive developmental delay up to

severe mental retardation, seizures and autistic-like

behavior .

Incidence 1:12,000.

Current tests look for a combination of total biopterin

and dihydropteridine reductase from neonatal blood

spots.

The original 'Guthrie' test is being gradually replaced by

chromatography, fluorometry or mass spectrometry.

Early diagnosis and treatment reduce the risk of

neurological handicap from 80-90% to 6-8% .

Incidence 1:12,000.

Current tests look for a combination of total biopterin

and dihydropteridine reductase from neonatal blood

spots.

The original 'Guthrie' test is being gradually replaced by

chromatography, fluorometry or mass spectrometry.

Early diagnosis and treatment reduce the risk of

neurological handicap from 80-90% to 6-8% .

PKUPKU

• Also called branched-chain ketoaciduria, is an

autosomal recessive metabolic disorder affecting

branched-chain amino acids. It is one type of

organic acidemia .The condition gets its name from

the distinctive sweet odor of affected infants' urine.

• The compound responsible for the odor is sotolon

Infants with this disease seem healthy at birth but if

left untreated suffer severe brain damage and

eventually die

MSUDMSUD

A diet with minimal levels of the amino acids

leucine, isoleucine, and valine must be

maintained in order to prevent neurological

damage

Hyperhomocysteinemia :This condition is a

significant risk factor for the thrombosis,

neuropsychiatric illness, and fractures.

Vitamin B6 can improve the condition as vitamin B6-

dependent trans-sulphuration pathway that

converts Hcy to cysteine

Homocysteine Homocysteine

Diagnosed by plasma

acylcarnitines, and urine organic

acids can be helpful

• MCAD: Medium-chain acyl-CoA

dehydrogenase deficiency

• VLCAD: Very long-chain acyl-

CoA dehydrogenase deficiency

• LCHAD: Long-chain L-3-OH

acyl-CoA dehydrogenase

deficiency

• TFP: Trifunctional protein

deficiency

• CUD: Carnitine uptake defect

Fatty Acid DisordersFatty Acid Disorders

Medium chain acyl-CoA dehydrogenase

deficiency (MCADD) is the most

common fatty acid oxidation disorder

which had been implicated in several cases

of sudden infant death syndrome.

MCCADMCCAD

Organic acids are breakdown products of protein and fatty acid metabolism. Defects in breakdown lead to:

Vomiting, metabolic acidosis, elevated ammonia in crisesID, motor delay, ataxia, cardiac/renal/pancreatic problems

Diagnosed by urine organic acids and/or plasma acylcarnitines

IVA: Isovaleric acidemiaGA I: Glutaric acidemia type IHMG: 3-OH 3-CH3 glutaric aciduriaMCD: Multiple carboxylase deficiencyMUT: Methylmalonic acidemia (mutase deficiency)3MCC: 3-Methylcrotonyl-CoA carboxylase deficiencyCbl A,B: Methylmalonic acidemiaPROP: Propionic acidemiaBKT: Beta-ketothiolase deficiency

Organic Acid DisordersOrganic Acid Disorders

+Prec (85.10): 0.401 to 1.202 min from Sample 9 (BADER) of AC 101003 DATA.wiff (Turbo Spray... Max. 3.5e4 cps.

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

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

55%

60%

65%

70%

75%

80%

85%

90%

95%

100%

Re

l. In

t. (%

)

*

* * * *

*

C2

100%

Inte

ns

ity

* internal standards

Control

+Prec (85.10): 0.401 to 1.202 min from Sample 8 (PATE) of AC 101003 DATA.wiff (Turbo Spray) Max. 3.8e4 cps.

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

5%

10%

15%

20%

25%

30%

35%

40%

45%

50%

55%

60%

65%

70%

75%

80%

85%

90%

95%

100%

Re

l. In

t. (%

)

Inte

ns

ity

100%

*

* * *

*

*

MCAD

C2

C16

C8

C10:1C6

MS/MS Plasma Acylcarnitines MS/MS Plasma Acylcarnitines

EndocrinopathiesEndocrinopathies

• The most commonly included disorders of the endocrine system

are congenital hypothyroidism (CH) and congenital

adrenal hyperplasia (CAH).

• Congenital hypothyroidism

• Breathing problems, anemia, slow heart rate, delayed milestones,

poor weight gain and growth, hearing loss, jaundice

• Screening for CH is done by measuring thyroxin (T4),

thyrotropin (TSH) or a combination of both analytes

• CH was added to many newborn screening programs in the

1970s, often as the second condition included after PKU.

• The most common cause of CH is dysgenesis of the thyroid

gland

• Early hormonal substitution can control the condition.

Congenital adrenal hyperplasia• Elevated 17-hydroxyprogesterone

(17OHP) is the primary marker used when screening for CAH, most commonly done using enzyme-linked immunosorbant assays, tandem mass spectrometry test to reduce the number of false positive results.

• Classic CAH is caused by a deficiency of the enzyme steroid 21-hydroxylase, and comes in two forms - simple virilizing and a salt-wasting form.

• Treatement is steroids.

HaemoglobinopathiesHaemoglobinopathies

Scikle cell disease

• A sickle cell test is a blood test done to screen for sickle cell

trait or sickle cell disease.

• The red blood cells deform because they

contain an abnormal type of hemoglobin,

called hemoglobin S, instead of the normal hemoglobin.

The best way to screen for sickle cell trait or sickle

cell disease is high-performance liquid

chromatography (HPLC) .

These tests identify which type of hemoglobin is

present. To confirm the results of HPLC, a genetic

test may be done.

Penicillin has been used in children with sickle

cell disease, blood transfusions for patients

identified with severe thalassemia.

Penicillin has been used in children with sickle

cell disease, blood transfusions for patients

identified with severe thalassemia.

Cystic fibrosisCystic fibrosis

Also known as mucoviscidosis, is an

autosomal recessive genetic disorder. It

affects most critically the lungs, and also the

pancreas, liver, and intestine. It is

characterized by abnormal transport of

chloride and sodium across an epithelium,

leading to thick, viscous secretions.

• CF is caused by a mutation in the gene for

the protein cystic fibrosis transmembrane

conductance regulator (CFTR)

• The newborn screen initially measures for raised blood concentration of immunoreactive trypsinogen. Infants with an abnormal newborn screen need a sweat test .

• People with CF have increased amounts of sodium and chloride in their sweat. In contrast, they have less thiocyanate and hypothiocyanite in their saliva and mucus. CF can also be diagnosed by identification of mutations in the CFTR gene.

• No cure for cystic fibrosis but early

diagnosis can improve the codition

• The cornerstones of management are

proactive treatment of airway

infection, and encouragement of good

nutrition and an active lifestyle.

• Recently therapies such as

transplantation and gene therapy

aim to cure some of the effects of

cystic fibrosis

Urea cycle disordersUrea cycle disorders

Disorders of the distal urea cycle, such as citrullinemia,

argininosuccinic aciduria and argininemia are included in

newborn screening programs in many jurisdictions that using

tandem mass spectrometry to identify key amino acids.

Proximal urea cycle defects, such as ornithine transcarbamylase

deficiency and carbamoyl phosphate synthetase deficiency are

not included in newborn screening panels because

A. They are not reliably detected using current technology

B. Severely affected infants will present with clinical symptoms

before newborn screening results are available.

Some regions claim to screen for

HHH syndrome (hyperammonemia,

hyperornithinemia, homocitrullinuria)

based on the detection of elevated

ornithine levels in the newborn

screening dried blood spot

1

SCID has not been added to

newborn screening

2

It requires PCR is not commonly

used

3

Follow-up and treatment of

affected infants also requires skilled immunologists,

4

Treatment for SCID is a stem cell transplant

Severe combined immunodeficiencySevere combined immunodeficiency

Others recently added disordersOthers recently added disorders

Duchenne muscular dystrophy

• X-linked disorder caused by

defective production of dystrophin.

• Many jurisdictions around the world

have screened for DMD using

elevated levels of creatine kinase

measured in dried blood spots

GalactosemiaGalactosemia

• Galactosemia occurs when an enzyme

galactose-1-phosphate uridyl transferase

deficient or not woking properly.

• (Coagulopathy, sepsis, severe jaundice,

developmental delay

• Treatment Restrict milk products

Biotinidase DeficiencyBiotinidase Deficiency

Caused by a lack of the enzyme biotinidase

Seizures

Developmental delay

Progressive hearing loss

Skin problems – eczema

Treated with biotin

• Screening for G6PD: by measuring the level of the

enzyme can prevent haemolytic crisis especially if family

history is present.

• Screening for diabetes: by measuring the level of IGF-1.

• Screening for hyperbilirubinaemia: by measuring total

and direct serum bilirubin.

SummarySummary

• All Neoborn All Neoborn Infants should benefit from newborn

Infants should benefit from newborn

screening systemsscreening systems

• Not all conditions Not all conditions are good candidates for screening

are good candidates for screening

– Should occur “often enough” to justify mass

Should occur “often enough” to justify mass

screeningscreening

– Early treatment is effective, accepted and

Early treatment is effective, accepted and

availableavailable

– Test is simple, safe, valid, precise, acceptable

Test is simple, safe, valid, precise, acceptable

• Screening is part of a system of follow-up, diagnosis,

Screening is part of a system of follow-up, diagnosis,

treatment and evaluationtreatment and evaluation

Refuse screening2

3 Confidentiality and privacy protections

Be informed about screening

1

Parents, on behalf of their children, have the right to

Parents and consumers must be involved in all parts of the policy-making and implementation process

Pitfalls of Newborn ScreeningPitfalls of Newborn Screening

Pitfalls of Newborn ScreeningPitfalls of Newborn Screening

• Not collecting newborn screening sample prior to transfusion Not collecting newborn screening sample prior to transfusion

because the baby is “too young” or has not yet been fedbecause the baby is “too young” or has not yet been fed

– Transfusions and feeding history alter results of some, but not

all of the newborn screening tests.

– Card has place to list transfusions, time of first feeding,

antibiotics, overall health and birthweight.

• Meaningful interpretation of test results takes all those bits

of information into account.

• Not collecting an adequate newborn screening sampleNot collecting an adequate newborn screening sample

– Most newborn screening tests are quantitative.

• More or less blood means higher or lower values and may

lead to false positives or negatives.

• Diagrams of correct circle filling are meant to ensure that the

appropriate amount of blood is on the filter paper, and that

there is no evidence of dilution (with alcohol, for example)

• Assuming that an abnormal newborn screen is a false positive Assuming that an abnormal newborn screen is a false positive

because the baby is well and/or because factors known to be because the baby is well and/or because factors known to be

associated with a false positive are present.associated with a false positive are present.

– This runs counter to the whole purpose of newborn screening,

which is to pick up kids BEFOREBEFORE they are symptomatic

Thank you