All new parents should be aware of the importance of the newborn screening test—a simple, routine way to protect your child from potentially life-threatening illness. This blood test can detect diseases that would otherwise not be apparent—in time for them to be treated.
To understand the newborn screening test, it’s important to look at its history. The test was initially developed to prevent mental retardation by promptly treating a rare disease called phenylketonuria (PKU).
In 1934, Dr. Asbjorn Folling first recognized PKU—a defect or deficiency in the enzyme that processes phenylalanine. Without an effective enzyme, the buildup of phenylalanine damages the developing nervous system—causing mental retardation and seizures. Doctors could treat infants with this disease by limiting their intake of phenylalanine, a substance found in proteins such as standard infant formula and breast milk. The problem was that the infants were healthy at birth and had no signs of the disease, so doctors and parents didn’t know which children to treat with this restricted diet. Dr. Robert Guthrie solved this problem by developing a simple test, using a drop of blood on filter paper, to test newborns for this disease. This was the birth of the newborn screening test.
The newborn screening test has expanded significantly, but it still follows the same principle and is conducted similarly. Newborn screens vary by state. In California, blood samples are tested for the following diseases:
- Metabolic diseases (including PKU) that makes the body unable to use certain parts of food for energy, growth or repair
- Endocrine diseases that cause the body to make too much or too little of a hormone, which can affect growth and development
- Hemoglobin diseases, which cause anemia by affecting the type or amount of hemoglobin in the red blood cells
- Cystic fibrosis, a common chronic lung disease in children
As medicine and genetic research advances, we’re able to identify more genetic diseases. As new tests become available, each new test must undergo a rigorous ethical discussion in order to be included in the newborn screen. The Institute of Medicine (IOM) has suggested three key principles for inclusion in newborn screening:
- Identification of the condition must provide a clear benefit to the child.
- A system must be in place to confirm the diagnosis.
- Treatment and follow up must be available for affected newborns.
For example, early identification of PKU can result in effective treatment and prevent mental retardation, clearly providing a benefit to the child. A test can confirm PKU and specialty care does exist.
On the other hand, we have a test for Huntington’s disease, but we have no effective treatment to alter the course of the disease. Therefore, choosing whether or not to test for Huntington’s disease is complex and made on an individual basis considering the potential psychological responses, the possibility for stigma or discrimination, and balancing this against the reduction of uncertainty in knowing whether one carries the gene. For these reasons Huntington’s disease does not meet the IOM standards and is not included on the newborn screening test.
Each state’s newborn screening program periodically reviews screening recommendations as new testing and new treatments become available. At that time these programs consider new additions and the possibility of eliminating certain tests.
To do a newborn screening test, a health care professional simply collects a few drops of blood from a baby’s heel and sends this sample to the newborn screening lab. Parents are notified if a child needs further evaluation, but it’s important to remember that requiring further screening doesn’t necessarily mean that a child has a disease or is sick.
All parents should be aware of the newborn screening test—a simple blood test that can save a child’s life.
— By Natasha Leman, M.D.
