Neonatal genetic metabolic disease screening

Newborn genetic metabolic disease screening (often referred to as "new screening" in the industry) is one of the public health projects with the highest cost-benefit ratio in the field of birth defect prevention and control. As long as there are no special contraindications, all newborns are recommended to complete the basic screening provided by the state for free. Whether to choose to pay for extended screening can be selected based on family medical history and reproductive history. There is no need to blindly follow the trend or deliberately avoid it.

The first time I truly realized the importance of this screening was when I met an out-of-town couple at the city’s maternal and child genetic counseling clinic two years ago. The eldest was diagnosed with phenylketonuria due to developmental delay when he was three years old. His brain damage has been irreversible and he cannot even speak complete sentences. ； When their second child was born, the couple followed the doctor's advice and underwent screening. On the third day after birth, he was diagnosed with the same disease. They have been insisting on eating a special formula powder with low phenylalanine. Now the baby is in the second grade of elementary school, and his test scores are better than many of his peers in the class.

Many new parents will wonder: My partner and I are both healthy, and our family has not heard of genetic diseases for three generations. Why should we check for this? In fact, the vast majority of hereditary metabolic diseases are autosomal recessive. If both parents are "normal" carriers of the disease gene, their children have a one-quarter chance of developing the disease. More than 80% of children diagnosed clinically have no relevant medical history in their families. I have also seen many parents who have just given birth to a baby. They are so tired that they can’t open their eyes. The nurse comes to hold the baby and step on the blood from the heel. Seeing the baby’s crying face turns red, she feels distressed and even asks if she can skip the test. First of all, the basic screening is paid for by the state, and you don’t have to pay a penny. Furthermore, choosing the heel blood test is not deliberately tormenting the baby. The newborn’s heel has the richest capillaries, the amount of bleeding is enough for detection, and the pain is much less than pricking the finger or pricking the arm.

The most controversial issue in the past two years is whether to add money for expanded screening ranging from hundreds to thousands of dollars, which can detect dozens or even hundreds of rare metabolic diseases. Practitioners in different fields actually have quite different opinions. My friend who is working on the new screening project at the Centers for Disease Control and Prevention has calculated that the 4-5 free basic diseases have a combined incidence rate of about 1/3000, and all of them have mature intervention programs. As long as they are detected and treated early, the children can grow and develop normally. ； Most of the other diseases in the expanded package have an incidence rate of less than one in 100,000, and more than 60% of them currently have no clear intervention methods. If they are detected, they will put unnecessary psychological pressure on the family, so he never recommends that ordinary families follow the trend and do expanded screening. But the genetic doctors I know in tertiary hospitals have a different view. If there has been a history of unexplained fetal arrest or miscarriage, or a child who died of unexplained premature death or had abnormal intellectual development, or the couple is a close relative, then expanded screening is necessary. Even if the child's disease is indeed incurable, the causative site can be clarified, and prenatal diagnosis can be done when preparing for pregnancy next time to avoid the same pitfalls again.

There is another piece of trivia that many people don’t know: the false positive rate of the new screening test is actually very high, so don’t panic until you get an abnormal notification. For example, almost 70% of positive initial screening tests for congenital hypothyroidism are caused by residual maternal hormones at birth or insufficient milk intake by the child during blood collection. Most of them are normal after re-examination. I met a new father before. He cried at home for three days after receiving the positive test result, but nothing happened during the retest. His eyes were swollen like walnuts when he came to get the report. He stood in the corridor crying and laughing.

After all, the new screening is the first health protection for a newborn baby. The free basic model is enough to cover most risks. Whether you want to add money to upgrade depends on the actual situation of your family. There is no need to listen to salesmen and buy expensive ones, and don't take the chance of "there is no genetic disease in my family, so I don't need to check" - after all, the one in 10,000 chance of encountering it is a 100% disaster for a family.