In China, birth defects caused by chromosomal diseases occur every year, and the incidence is increasing year by year.9 The most common prenatal screening in clinic is to extract AFP, uE3 and free-βHCG from the serum of pregnant women, calculate the risk value of chromosomal abnormality with Multiaale software, and screen out the critical high-risk group or high-risk group that may have some kind of chromosomal disease, so as to improve the accuracy of detection.10,11. The gene discussed is AFP; the disease is chromosomal disorder.