Unilateral and bilateral renal agenesis in monoamniotic twins

One of monoamniotic, monochorionic twins was born with absence of kidneys but had none of the extrarenal manifestations of Potter's syndrome other than low-set ears. His twin had a single kidney with anomalies but was capable of producing a normal amount of urine, and a normal quantity of amniotic fluid was present. These unique observations support the hypothesis that the facial, limb, pulmonary, and skin abnormalities of Potter's syndrome are due to oligohydramnios secondary to absence of intrauterine urine production.