Complete absence of both kidneys or severe bilateral dysgenesis is not compatible with life and the infant usually expires within hours of birth. Other abnormalities are usually also present in what is called the Potter sequence: lung hypoplasia (which is usually the direct cause of death), abnormal face with large floppy ears, epicathic folds, a parrot-beak nose, and receding chin. These conditions ar all thought to be secondary to the virtual absence of amniotic fluid. Positional foot defects, skeletal malformations and oesophageal and anorectal atresia are among the other malformation often found.
The incidence of renal dysgenesis is in the lower range of congenital birth defects -- around 1 to 2 per 10,000 births, but certain areas report higher rates. This is probably attributable to autopsy practices.