represent the most severe manifestation of an autosomal dominant condition with incomplete penetrance and variable expressivity. There are several genetic pathways that could result in this condition. In 2017 researchers identified heritable autosomal dominant mutations in the gene GREB1L in two unrelated families as being the cause of both BRA and URA utilizing Exome Sequencing and direct sequence analysis. This is the first reported genetic lesion implicated in the activation of Retinoic acid receptor (RAR) targets that has been associated with renal agenesis in humans. The majority of other possible candidate genetic pathways are autosomal recessive in nature and do not coincide with the frequency or penetrance at which BRA typically occurs in the human population. Additionally, candidate genetic pathways would be expected to involve genes expressed in the developing urogenital system (UGS). Often, these same genes and/or pathways of interacting genes are also expressed in the developing UGS as well as the central nervous system (CNS), gut, lung, limbs, and eyes. Pathogenesis Development of the mature kidney begins between weeks 5 and 7 of gestation. Fetal urine production begins in early gestation and comprises the majority of the amniotic fluid in the second and third trimesters of pregnancy. The fetus continuously swallows amniotic fluid, which is reabsorbed by the gastrointestinal tract and then reintroduced into the amniotic cavity by the kidneys via urination. Oligohydramnios occurs if the volume of amniotic fluid is less than normal for the corresponding period of gestation. The fetal urine is critical to the proper development of the lungs by aiding in the expansion of the airways - alveoli, by means of hydrodynamic pressure and by also supplying proline which is a critical amino acid for lung development. Alveoli are the small sacs in the lungs that exchange oxygen with the blood. If the alveoli, and thereby the lungs, are underdeveloped at the time of birth the infant will not be able to breathe air properly and will go into respiratory distress shortly after birth due to pulmonary hypoplasia (underdeveloped lungs). This is the primary cause of death to Potter sequence infants secondary to renal failure. The fetal urine also serves to cushion the fetus from being compressed by the mother's uterus as it grows. Prognosis The outcome of Potter's Sequence is poor. A series of 23 patients in 2007 recorded 7 deaths, 4 in the neonatal period. All 16 survivors have chronic kidney disease,