Objective To make a prenatal diagnosis on a 22-weeks pregnant who has abnormal fertility history and carries chromosome equilibrium ectopia.Methods Ultrasonography and prenatal diagnosis of amniotic fluid(chromosome karyotype CNV-seq)were used.Results The Ultrasonic examination shows that the child may be fetal mandible,fetal genital dysplasia and small penis.Prenatal diagnosis of amniocentesis shows that the fetal chromosome karyotype is 47,X?,+der(22)t(11;22)(q23.3;q11.1)mat.The testing results of human genome copy number variation(CNV)indicate that seq[hg19]11q23.3q25(116680000-134960000)×3,22q11.1q11.21(16840000-20320000)×3.Combining with clinical manifestations and laboratory test results,the child was diagnosed as Emanuel syndrome—a rare disease.Conclusion The prenatal diagnosis and family studies made on patients with abnormal fertility histories,abnormal chromosome carriers and the abnormal child through ultrasound,can clarify the cause of diseases.Therefore,the early detection,diagnosis and intervention are the key to reduce the birth of children.