PKU
All states screen newborns for phenylketonuria. This was the nation’s first newborn screening test, and it has been routinely administered since the 1960s. PKU affects one baby in 12,000. Babies with this disorder cannot process a part of protein called phenylalanine. As a result, without treatment, phenylalanine builds up in the bloodstream and causes brain damage and mental retardation. When this disorder is detected early, mental retardation can be prevented by feeding the baby a special formula. A special diet should be followed, perhaps indefinitely.
Hypothyroidism
The disorder most commonly identified by routine screening is congenital hypothyroidism, which affects one baby in 4,000. All states test newborns for this disorder. This is a thyroid hormone deficiency that retards growth and brain development. If it is detected in time, a baby can be treated with oral doses of thyroid hormone to permit normal development.
AIDS
The AIDS screening test, which detects HIV antibodies, is not reliable for an infant born to an infected mother. This is because the mother’s antibodies may be present in her baby’s blood for up to 15 months, even if the baby has not been infected. A new test that measures an immune system protein called lgA is proving accurate in diagnosing HIV in babies between the ages of 3 and 6 months. Researchers also recently reported the development of a test that detected the virus in 80% of infected newborns. There is evidence that medicating a pregnant woman who tests positive for HIV can reduce the risk of her baby becoming infected. Much research in this area is being done at this time. AIDS screening for both mother and child remains voluntary. Infants with AIDS are closely monitored and treated with antibiotics, immune globulin, and anti viral drugs.
Galactosemia
All states test newborns for galactosemia, which affects one baby in 60,000 to 80,000, and can cause blindness and mental retardation. A baby with galactosemia is unable to convert galactose, a sugar present in milk, into glucose, a sugar the body is able to use. As a result, milk and other dairy products must be eliminated from the baby’s diet.
Sickle Cell Anemia
In 1987, a National Institutes of Health panel recommended that all babies be screened for sickle cell anemia, an inherited blood disease. Currently, more than 30 states have begun screening for this disorder, which affects about one in 400 black babies in this country and also occurs with some frequency among people of Hispanic, Mediterranean, Middle Eastern and South Asian descent. Early treatment can prevent some of the complications of the disease. Young children with sickle cell anemia are especially prone to certain dangerous bacterial infections, such as pneumonia and meningitis. Studies have shown that treatment with penicillin, beginning by two months and continuing to about five years, can dramatically reduce the risk of these infections and the deaths that result from them. Newborn screening can alert the physician to begin antibiotic treatments before infections occur.
Cystic Fibrosis
Several states now test for cystic fibrosis, a disease which occurs in up to one in 2,000 white births and produces chronic respiratory disease, problems with digestion, and poor growth. Infections involving the lungs are especially serious, and some may be prevented with antibiotics. Recent improvements in treatment have led to longer and healthier lives for children with cystic fibrosis. Experimental gene therapy has begun for individuals with cystic fibrosis and may someday present a cure for affected children.
Adrenal Hyperplasia
A few states have begun testing for congenital adrenal hyperplasia. This disorder, in which certain hormones are deficient, affects genital development and can result in death in the newborn period due to loss of salt from the tissues. Lifelong treatment with the missing hormone suppresses this disease, which occurs in one in 12,000 births.
Biotinadase Deficiency
A fairly recent newborn screening test detects biotinadase deficiency. Biotinidase is an enzyme that recycles biotin, a B vitamin, in the body. A deficiency of this chemical, which occurs in one in 70,000 babies, may cause serious complications and even death. If the deficiency is detected in time, problems can be prevented by giving the baby extra biotin.