Newborn Screening
All infants born in the state of South Carolina are screened for SIX different metabolic and/or genetic disorders. The disorders screened for are Phenylketonuria (PKU), Galactosemia, Congenital Adrenal Hyperplasia (CAH), Congenital Hypothyroidism (CH), Medium Chain Acyl Co-A Dehydrogenase Deficiency (MCADD) and Hemoglobinopathies. Tests for these disorders are performed on blood obtained from infant heel stick and collected on special filter papers. The filter paper is attached to a test request form and are sent to the SC Bureau of Laboratories (BOL) for testing in the Newborn Screening (NBS) section laboratory.
The annual birth rate in SC is between 50,000 - 55,000.
Since PKU was the first metabolic disorder screened for in newborns starting about 30 years ago, many lay people and health professionals refer to NBS as the PKU test. As noted above, NBS in SC is performed for six disorders. All other states screen for at least three disorders. Therefore, it is IMPERATIVE that on the initial NBS, the request form must be checked for NBS tests and NOT PKU.
Click here to view the Newborn Screening F.A.Q. sheet.
Available Tests:
PHENYLKETONURIA (PKU)
PKU is caused by a metabolic enzyme deficiency which results in excess accumulation
of the amino acid phenylalanine in the blood. If this condition is not
detected and treated within the first 2-3 months of life, the infant will
become mentally retarded. It has been estimated that it would cost the
state approximately $30,000 a year to care for an institutionalized mentally
retarded individual. Considering a life expectancy of 50 years, this cost
would total $1,500,000 for the lifetime of each individual.
However, with early detection, dietary treatment with special formula will
lower the phenylalanine levels and PKU induced mental retardation will be
prevented. SC provides persons with PKU special dietary formula free of charge,
at the present time. This policy is subject to change based on availability
of funds. The state also provides free follow-up testing, as requested, on
blood spot specimens from the affected individual for the rest of their lives.
This follow-up testing helps the nutritionist/dietician to monitor the amount
of phenylalanine the child or adult is receiving in their diet. Although
previously thought that PKU individuals only needed to be on a special diet
through puberty, it is now strongly recommended that these individuals adhere
to the diet for their entire life. Individuals who adhere strictly to the
special diet for the rest of their lives will not have any growth or developmental
problems due to their PKU disorder.
Based on SC birth rate and known incidences, SC expects to detect 2-3 infants
with PKU each year.
GALACTOSEMIA
Galactosemia is caused by a metabolic enzyme deficiency which results in
excess accumulation of galactose in the blood. Galactose is a component
of lactose which is a sugar present in both cow's milk based formula and
breast milk. Therefore, infants with Galactosemia will appear healthy until
they are fed milk containing lactose. The symptoms of Galactosemia infant
can be failure to thrive, vomiting, diarrhea, hepatomegaly, and jaundice.
If this condition is not detected and treated early the infant will become
mentally retarded or, in many instances, die. Although treatment with non-lactose
formula and subsequent special diet helps, it will not always prevent the
onset of mental retardation or eventual early death.
Based on SC birth rate and known incidence of Galactosemia, SC expects to detect one infant with Galactosemia each year.
CONGENITAL HYPOTHYROIDISM (CH)
CH is caused by a thyroid metabolic defect which results in low levels of
Thyroxine (T4) in the blood. Since the thyroid is not producing enough
T4, these infants are also characterized with an increased level of thyroid
stimulating hormone (TSH). If not detected and treated early the low levels
of T4 can cause the infant to become mentally retarded and/or have poor
growth development. T4 replacement therapy will prevent growth problems
and will improve mental development.
Based on SC birth rate and known incidence of CH, SC expects to detect 10 infants with CH each year.
HEMOGLOBINOPATHIES
Hemoglobinopathies are the result of genetic defects. The most prevalent
and one of the most deleterious Hemoglobinopathies are sickling disorder
hemoglobins which include sickle cell anemia. It has been shown that undetected
infants with sickling disorders are highly susceptible to infections leading
to death within several months of life. Early detection and prophylactic
antibiotic treatment of these infants, greatly reduces the chances of these
early infections.
Infants with one sickling hemoglobin gene and one normal gene are considered to have an abnormal hemoglobin trait. Although these infants are clinically normal and will not have any problems related to the hemoglobin trait, the infants' parents may want to be tested to determine if subsequent children could inherit a sickling disorder.
Based on SC birth rate and known incidence of Hemoglobinopathies, SC expects to detect 100 infants with some type of sickling hemoglobin disorder each year. Screening also identifies approximately 2200 infants with hemoglobin traits each year.
Follow-up is usually carried out by appropriate regional genetic groups. Genetic counseling should be performed by a qualified physician.
CONGENITAL ADRENAL HYPERPLASIA (CAH)
CAH is the result of a metabolic enzyme deficiency which results in excess
accumulation of certain steroids in the blood. Elevated levels of one of
these steroids, 17-Hydroxyprogesterone, are considered indicative of CAH.
However, further evaluation is necessary to confirm CAH. There are several
forms of CAH, including salt wasting, simple virilizing, and non-classical.
Salt wasting is the most deleterious form and results in adrenal crises
within a few weeks of life. If not treated promptly the infant can die.
Based on SC birth rate and known incidence of CAH, SC expects to detect 3-4 infants with CAH each year.
MEDIUM CHAIN ACYL CO-A DEHYDROGENASE DEFICIENCY (MCADD)
MCADD is an inborn error of fatty acid oxidation that can cause significant
morbidity and mortality in the newborn. It is an autosomal recessive disease
with the variant gene located on chromosome one. It usually presents in
infancy or early childhood with hypoketotic hypoglycemia and encephalopathy
after an inter-current illness and/or period of poor oral intake. Approximately
20% of infants with MCADD die before diagnosis, and a substantial proportion
of the survivors have significant residual problems from an initial crisis.
Children who survive the initial crisis have exhibited the following long-term
outcomes: developmental and behavioral disability, speech/language delays,
chronic muscle weakness, failure to thrive, cerebral palsy and attention
deficit disorder. Pre-symptomatic detection will allow for treatment to
begin before such a crisis occurs. Children with MCADD usually get sick
for the first time between two months and two years of age, but some children
get sick as early as two days of age or as late as six years of age. MCADD
may cause 1 to 3 percent of infant deaths attributed to Sudden Infant Death
Syndrome (SIDS). Based on SC birth rate and known incidence of MCADD, SC
expects to detect four infants with MCADD each year.
HEMOGLOBINOPATHIES (ADULT)
Hemoglobinopathy analyses are performed on adult specimens received from
sickle cell clinics, county health clinics, veteran administration clinics,
and other facilities. The testing is primarily done in support of clinical
monitoring and treatment programs at these various medical facilities.
The laboratory often is requested by various hospitals in the state to
assist in identifying rare hemoglobin variants.