Table 2.
Common major structural malformations in the trisomy 18 syndrome
| Frequency | Organ/System | Prevalent type of malformation |
|---|---|---|
| Common (>75%) |
heart |
septal defects, patent ductus arteriosus, and polyvalvular disease |
| Frequent (25-75%) |
genitourinary |
horseshoe kidney |
| Less frequent (5-25%) | gastrointestinal |
omphalocele, esophageal atresia with tracheo-esophageal fistula, pyloric stenosis, Meckel diverticulum |
| central nervous system |
cerebellar hypoplasia, agenesis of corpus callosum, polymicrogyria, spina bifida |
|
| craniofacial |
orofacial clefts |
|
| eye |
microphthalmia, coloboma, cataract, corneal opacities |
|
| limb | radial aplasia/hypoplasia |