Trisomy 18 with multiple rare malformations: report of one case.

Trisomy 18 syndrome is the second most common multiple malformation syndrome. The incidence is about 0.3 per 100 newborn babies. More than 130 different abnormalities have been noted in the literature on patients with the trisomy 18 syndrome. Trisomy 18 includes a broad spectrum of anomalies and malformations, among which we found Dandy-Walker malformation (DWM) rarely mentioned. DWM is estimated to occur in approximately 1 in 25,000 to 30,000 live births. The major components of DWM are the following: partial or complete absence of the cerebellar vermis, a posterior fossa cyst continuous with the fourth ventricle, and hydrocephalus. Although DWM has been associated with many chromosomal abnormalities and genetic syndromes in live birth, trisomy 18 with DWM is a rare condition. Here we present a female newborn with intrauterine growth retardation and multiple congenital abnormalities including: craniofacial anomaly, tracheoesophageal fistula, esophageal atresia, absent radius and thumb, short ulna, clenched hands, ventricular septal defect, coarctation of the aorta, patent ductus arteriosus, Meckel's diverticulum, ectopic pancreas in the ileum, and DWM. Her chromosome karyotype was 47,XX,+18. This is a case of Trisomy 18 with multiple rare malformations.