The incidence of this disease, also known as Edwards syndrome, ranges from 1/4000 to 1/8000 of live births, with a male to female ratio of 1:3 to 1:4. Children with this disease have a short life span and die shortly after birth, and those who survive have severe mental retardation. The majority of cases are trisomic with all cells of chromosome 18, while a few are chimeric and partial trisomies of chromosome 18 caused by chromosome break heterotaxy. The child is characterized by posterior occipital protrusion, narrow forehead, small head, wide fontanelle, low ears with malformation, short eye fissures, small jaw, internal canthus, drooping eyelids, cleft lip or cleft palate. Short neck, excess skin on the neck, inguinal or umbilical hernia, tracheoesophageal fistula, biliary atresia. Horseshoe or ectopic kidney, double urethra, hydronephrosis and polycystic kidney. Hypoplastic external genitalia, hypospadias, cryptorchidism in males and large clitoris in females. The child has mental retardation, high muscle tone, hydrocephalus, meningocele, cerebellar hypoplasia, and corpus callosum hypoplasia. Hand clenched, thumb, index finger, middle finger tightly closed, index finger pressed on middle finger, little finger pressed on ring finger, little finger or all fingers only 1 transverse stripe, thumb hypoplasia or missing, through hand. Cradle foot, clubfoot, syndactyly, polydactyly, short sternum, limited hip abduction. Hypoplastic thyroid and adrenal glands, bicornuate uterus, coronary artery malformation, transposition of the great arteries, tetralogy of Fallot, etc. Resuscitation is often required at birth. Low capacity for life, often apnea, poor sucking, and mostly nasal feeding. Despite careful care, most die within the first 2 months, and very few children survive to 1 year of age, all with severe mental retardation.