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PURSUING
NEWBORN SCREENING
National
Testing Facilities
Baylor
University Medical Center • 1-800-4BAYLOR
baylorhealth.com/BaylorsBest
Currently,
one of two places that performs national newborn screening. Parents interested
in having their baby screened for metabolic disorders can contact the university
for a complete packet detailing the process. Price for newborns to 4 months
is $25; for babies 4 months and older, $50.
Neo-Gen
Screening - www.neogenscreening.org
The
second of two facilities offering national newborn screening. Access the
website for more info.
Newborn
Screening Advocacy groups
Tyler
for Life Web Site -
tylerforlife.com
FOD
Family Support Group - fodsupport.org
Children
Living With Inherited Metabolic Disease (CLIMB) - climb.org.uk
National
Organization for Rare Disorders (NORD) - rarediseases.org
|
by
Lisa
Wells
staff,
Nashville Parent Magazine
Metabolic
disorders take the life of one baby in every 4,500. Tennessee considers
all but five of these disorders too rare to test for - but isn't it worth
it if it saves a newborn's life?
About
24 hours after birth, a nurse takes a small blood sample from each infant
born in the state of Tennessee. The blood is dropped onto a piece of filter
paper and sent to the Tennessee Department of Health, Newborn Screening
Program laboratory in Nashville. The presence of district chemical signatures
in the blood sample are a warning signal to doctors and parents that the
infant may have one of four debilitating genetic disorders.
None
of these disorders are common or curable. However, strict dietary and medical
precautions can prevent developmental retardation and fatalities in the
affected children. Because early diagnosis is crucial, the state mandates
that every child born in Tennessee be tested. But there are still many
other disorders newborns aren't tested for. Should the additional tests
be added?
Melanie
and Dell Ruff definitively believe so. They nearly lost their daughter,
Anna Katherine, to a rare but treatable genetic disorder.
Anna
Katherine was an active, healthy and happy 17-month-old when she became
ill with a common stomach virus. Anna Katherine's reaction was far from
normal. She began with the normal stomach flu symptoms - lack of appetite,
vomiting and diarrhea. But after a day and a half, Anna Katherine became
lethargic and unresponsive. After consulting with her doctor, Anna Katherine
was rushed to the emergency room.
In
the hospital, a blood sugar test showed that Anna Katherine had abnormally
low blood sugar. Intravenous glucose saved her life. The doctors at the
hospital were unable to explain her symptoms. One week later, after an
array of blood tests, Anna Katherine was diagnosed with MCAD (Medium Chain
Acyl CoA Dehydrogenase Deficiency). People with MCAD cannot convert stored
fat to blood sugar. As Anna Katherine's body ran out of blood sugar, she
was unable to access her body's natural energy reserve and her blood sugar
dropped to critical levels.
During
the past decade, screening tests for MCAD, and more than 30 similar genetic
disorders, were developed. The new tests are done with a technique called
Tandem Mass Spectrometry at three laboratories in the United States. For
the infant, the test is no different from that currently performed in Tennessee
- a small pinprick to the heel. Blood is dropped onto a filter paper postcard
and sent to the laboratory. The laboratory cost of the test is usually
less than $25.
These
disorders are all rare; most occur in fewer than one in 60,000 children
with a combined incidence of about one child in 4,500. Some of the disorders
occur most frequently in specific genetic groups. For example, sickle cell
disease is most common to people of African or Mediterranean heritage,
and maple syrup urine disorder is most common in Mennonite populations.
Only
a few states have made comprehensive newborn screening mandatory. Tennessee
has yet to expand the list beyond what can be done in the Department of
Health laboratories. To date, the legislature has decided that the additional
cost of testing is not warranted by the incidence of these diseases in
Tennessee. But if only one baby were spared ...
Cheryl
Major, R.N.C., B.S.N., outreach coordinator for Vanderbilt University's
Division of Neonatology, points out that tests are not as simple as they
first appear. Nurses must be trained to collect the blood in a specific
manner. Too much, too little or multiple drops of blood spoil the sample.
Testing
difficulties are increased at hospitals, like Vanderbilt, that treat large
numbers of sick or premature infants. Because the tests look for waste
products of the digestive process, the blood sample must be collected after
the child has begun feeding. However, for other disorders, the sampling
must occur before transfusion. Meeting these criteria can be impossible
in sick babies and a return visit to the hospital is required to meet state
regulations.
A
Matter of Ethics
New
ethical considerations arise as our understanding of the genetic causes
of disease increases. It is possible to test for diseases for which there
is no treatment. Do we want this information? Do we want doctors, insurance
companies or the government to have access to our genetic information?
Technology is currently outpacing the societal ethics and some argue that
we should refrain from comprehensive testing until ethical and legal considerations
have been addressed.
In
Tennessee, the current screening program looks for symptoms of phenylketonuria,
galactosemia, hypothyroidism and hemoglobinopathies (the most common of
which is sickle cell disease). Some time in the coming year, the state
will add congenital adrenal hyperplasia to its routine screening program.
Most of these disorders are autosomal recessive, meaning both parents must
be carriers of the disorder for it to be passed on to the child. When both
parents are asymptomatic carriers of the disorder, each of their children
have a one-in-two chance of having the disorder.
Tennessee
Department of Health laboratories are able to return positive test results
within three days of receiving the sample. In the event of a positive result,
the test is repeated to confirm the results. Quick treatment can be crucial
to the development of these children; relying on out-of-state laboratories
may compromise the care of some patients.
The
state mandates that five tests (see sidebar) be done on the basis of cost,
incidence and accessibility. But parents of children with one of the other
rare metabolic disorders are pleading with the state to require more comprehensive
screening. They argue that for a small initial investment, many lives can
be saved in addition to the societal and financial costs of treating children
who are diagnosed too late and develop severe physical problems.
Because
mandatory comprehensive testing is unlikely in the immediate future, parents
who have special concerns should talk with their pediatrician. Because
the disorders are genetic, a family history of unexplained infant deaths
or developmental retardation may be indications that additional testing
should be done. Unfortunately, because these are recessive disorders, there
may be no indication that a family carries the faulty genes.
Newborn
Screening Program - Required Tests in tennessee
Phenylketonuria
(PKU)
PKU
is a congenital metabolic impairment. Children with PKU are unable to digest
the amino acid phenylalanine. There are no symptoms in early infancy. Developmental
retardation symptoms are observed between 6 and 12 months of age. This
disorder can be treated with strict dietary restriction of phenylalanine.
Special formulas and food are required throughout childhood and adolescence.
Galactosemia
Galactosemia
is an inherited metabolic disorder that is usually fatal. Children with
this disorder cannot convert milk sugar (galactose) to usable glucose,
and their bodies therefore cannot develop normally. Treatment requires
a lactose-free diet. For good results, treatment for the disorder must
begin within 10 days of birth.
Hypothyroidism
Hypothyroidism
results from decreased thyroid function. Symptoms may not appear until
the infant is several months old. Children with this disorder may have
mental retardation, growth failure and deafness, among other symptoms.
If treatment with synthetic thyroid hormones is begun within a month of
birth, children generally develop normally.
Hemoglobinopathies
Hemoglobinopathies
are a class of genetic disorders that affect the kind and amount of red
blood cells. Sickle cell disease occurs most commonly in people of African
or Mediterranean heritage. These diseases can be fatal and result in a
variety of physical problems. Treatment usually entails fluid therapy,
analgesics and transfusion.
Congenital
Adrenal Hyperplasia
In
the year 2000, the state will begin testing for congenital adrenal hyperplasia.
This disorder is the result of defects in the natural production of sexual
hormones and can cause ambiguous genitalia in girls. It also impacts the
uptake and retention of salt; the inability to retain salt can be fatal
to newborns. Treatment is complicated but available.
Lisa
Wells is a mother and freelance writer. |