Trisomy 13, also known as Patau’s syndrome, is caused by an extra chromosome 13 in the genome of somatic cells and has a prevalence of 1/10,000 live births, significantly more in females than males. 13-trisomy occurs mainly due to chromosome non-separation during germ cell meiosis. The characteristic manifestations include: forebrain anomalies; postaxial polydactyly; scalp defects in the occipital region and malformations of the eyes, nose and lips. 80% of children with trisomy 13 are born with low birth weight and have total forebrain defects with varying degrees of olfactory and optic nerve hypoplasia and severe mental retardation. Moderate microcephaly, receding forehead, both temporal narrowing, wide sagittal suture and fontanelle; wide eye spacing, microphthalmia, iris defect, retinal hypoplasia; cleft lip, cleft palate or both; deafness, auricular malformation with or without ear hypoplasia; 60% have throughhandedness, extremely high axial triple shooting, multiple bowed fingers, radial skip pattern in the ring finger, markedly protruding narrow nails, curved fingers, and heel retrusion. There is no special treatment. The prognosis of the children is poor, about 80% die within 1 month after birth, with an average survival of 130 days, and the survivors all have severe mental retardation and other deformities. Patients with mosaicism have a longer survival time. Prevention: 1. Those with a history of typical 13-trisomy or other trisomy pregnancy will have a higher risk of 13-trisomy or other trisomy reoccurrence; prenatal screening and prenatal diagnosis with ultrasound are required. 2. The risk of reoccurrence in familial Robertsonian translocation carriers is about 1-5%. If one of the two parents is a Robertson translocation carrier, almost 100% miscarriage will occur because only trisomic or monosomic congeners can be produced. 3. For those who have a history of 13-trisomy childbirth, prenatal diagnosis must be performed when they become pregnant again. The use of CGH microarrays for clinical diagnosis in recent years has also brought new prospects for prenatal diagnosis of trisomy 13.