Screening for genetic metabolic diseases

For newborns and high-risk groups with family genetic history and adverse pregnancy and childbirth history, it is currently the most cost-effective means of preventing and controlling birth defects. As long as more than 70% of screen-positive children initiate standardized intervention before the onset of the disease, they can avoid irreversible brain damage, organ failure and other serious consequences, and even have a lifespan and quality of life that is exactly the same as that of healthy people.

Don’t mention the couple from Wenzhou I met at the pediatric genetics clinic two years ago. I feel pity when I think about it now. My first-born child was not screened when he was born. When he was six months old, he suddenly developed convulsions and was slow to chase objects. He was taken to a large hospital for a check-up and was diagnosed with classic phenylketonuria. By then, the brain damage was irreversible. He spent hundreds of thousands on rehabilitation, but he could barely sit up and couldn't even call his parents. Later, I became pregnant with my second child. I came here for a prenatal screening right after I was pregnant. After the child was born, I took a heel blood test and it was confirmed that he carried the pathogenic variant but it was still within the controllable range. I drank special formula milk powder from the first day of birth. Now the little one is in the middle class of kindergarten. The last time I came for a review, he gave me a candy I drew by myself. He was very smart. To put it bluntly, the tandem mass spectrometry technology currently used is that one drop of heel blood can detect a host of diseases. It is very fast, and the results are available in two or three days. The cost of two to three hundred yuan can really withstand the risk of a family's collapse.

Some people may ask at this point, does everyone have to do the full set? In fact, the industry does not have a completely unified view on this matter. One group is a staunch "screen for everything" group. They feel that now that technology has become popular, many places have even included four high-risk genetic metabolic diseases into free screening. Even if the incidence rate is one in hundreds of thousands, it would be a 100% tragedy if it really falls on a family. If you can, do it. Don't save money and gamble on the odds. The other group advocates "accurate screening", saying that ordinary families without high-risk factors do not need to blindly undergo full-spectrum screening worth thousands of dollars. The incidence of many rare diseases is lower than winning the lottery. Instead, it is easy to detect a bunch of genetic mutations of unknown clinical significance. Worrying throughout the pregnancy is purely unnecessary mental exhaustion. Both views are reasonable. No one is right or wrong, it's just that they come from different perspectives.

Many people think that this screening is only required for newborn children, but this is not true. Last year, a 28-year-old girl came to me. She had been pregnant three times, all of which had fetal stoppages in the second trimester. She had checked her chromosomes and immune system, and everything was fine. Finally, she did a metabolic screening with the idea of ​​giving it a try, and found out that she had mild glutaric acidemia type I. She had no symptoms at all when the metabolic load was low, but problems started when the burden on her body increased during pregnancy. Later, she adjusted her diet and coenzyme supplementation plan. At the beginning of this year, she gave birth to a girl weighing more than 6 pounds. Both mother and daughter are healthy. We in the industry often say that "screening is for inadvertent treatment", and it is really apt in these cases. If detected three months early, it may save the money for medical treatment in the next thirty years.

Of course, don’t take this screening as a panacea. It is only a preliminary screening, and the false positive rate is actually not low. Hey, to be honest, many parents feel weak when they see the word "positive" on the report. In fact, it is really unnecessary. The sensitivity of the initial screening is set high to prevent suspicious cases from being missed. False positives are part of the design. Almost every week, I meet parents who come in crying with a positive preliminary screening report, thinking that their child must be seriously ill. However, when the urine gas chromatography mass spectrometry and gene sequencing are reviewed, more than 90% of them are false positives, and they cry for days in vain. So don’t panic if you really get a positive report. Just follow the doctor’s instructions and go to a higher-level institution for a diagnosis. In many cases, it’s just a false alarm.

I usually give advice to people who consult, and I don’t push projects hard. If you have a relative who died of unknown reasons in your family, or you have given birth to a child with developmental abnormalities before, or your husband and wife are close relatives, you don’t have to worry about it, just do the full spectrum, and you can buy it for a few hundred yuan. If there are no high-risk factors, just do the high-risk ones that are free in the local area. There is really no need to follow the trend and buy tens of thousands of screening packages. Not to mention the money spent, it will only cause trouble for yourself.

To put it bluntly, in the final analysis, this screening is a tool for risk prevention and control. It is never a moral kidnapping of "if you don't do it, you will be sorry for the child", nor is it a guarantee of "if you do it, you will be 100% healthy". How to choose actually depends on how much money you are willing to spend and how much anxiety you are willing to bear in order to avoid small-probability risks.