The main symptom: malformation The disease was first described by Patau in 1960 and is therefore also known as Patau syndrome. The incidence in neonates is approximately 1:25,000, with females being significantly more common than males. Clinical manifestations: The malformations and clinical manifestations of the affected children are much more severe than in trisomy 21. Craniofacial deformities include small head, defective forehead and forebrain development, small eyes, often with iris defects, wide and flat nose, 2/3 of the children have cleft upper lip and often cleft palate, low ear position, auricular deformity, small jaws, other common multiple fingers (toes), fingers overlapping, heel protrusion and mid-foot convexity, forming the so-called rocker bottom foot. Males often have scrotal malformations and cryptorchidism, while females have clitoral hypertrophy, double vagina, bicornuate uterus, etc. Malformations of the brain and internal organs are very common, such as anosmia, ventricular or atrial septal defects, patent ductus arteriosus, polycystic kidneys, hydronephrosis, etc. Deafness is caused by defects in the spiral apparatus of the inner ear. Mental retardation is seen in all patients and is severe, with seizure-like epilepsy and hypotonia in longer surviving children. The cytogenetic and genetic counseling cases are free trisomy 13 with karyotype 46, XX (or XY), +13, and the rest are chimeric or translocated. The chimeric type is generally less symptomatic, and the translocation type usually has a predominance of 13 and 14 Roche translocations. Patients have a t(13q14q) translocation chromosome with karyotype 46, -14, +t(13q14q), which results in an extra long arm of 13. When one of the two parents is a balanced translocation carrier, the risk of producing an affected child is no more than 5% or 1% because the vast majority of abnormal fetuses are aborted and die The risk of delivering a child with this condition is no more than 5% or 1%. Etiology and prognosis Since little is known about the factors that contribute to the development of trisomy 13, advanced maternal age may be one of the causes, with a mean age of 31.6 years for mothers and 34.6 years for fathers of affected children. In addition, it is well documented that 79% of cases are conceived during the cold season (September-February), 45% of children die within the first month of life, 90% die within 6 months, and less than 5% survive to 3 years of age, with an average life expectancy of 130 days.