Edward's syndrome

47 XX 18

Most children with Edwards' syndrome die early in infancy, with fewer than 10% surviving beyond 1 year of age. The clinical features of Edwards' syndrome are low-set ears, small chin, microcephaly, overlapping fingers, rocker-bottom feet, cardiac defects (especially ventricular septal defects), renal anomalies and learning disability.

Patau's syndrome, or 47 XX 13, is characterised by structural defects of the brain, small eyes, polydactyly and cardiac/renal malformations. Most babies with Patau's syndrome do not survive beyond 1 year of age.