However, recent analysis has estimated that the condition may occur at a much greater frequency. The condition has been reported to occur twice as commonly in males as in females, suggesting that certain genes of the Y chromosome may act as modifiers. However, no candidate genes on the Y chromosome have yet been identified.BRA appears to have a predominantly genetic etiology and many cases 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.
The loss of function resulting from the required removal of a diseased organ is iatrogenic, as in the case of diabetes consequential to the removal of all or part of the pancreas. The incidence of iatrogenesis may be misleading in some cases. For example, a ruptured aortic aneurysm is fatal in most cases; the survival rate for treatment of a ruptured aortic aneurysm is under 25%. Patients who die during or after an operation will still be considered iatrogenic deaths, but the procedure itself remains a better bet than the probability of death if left untreated. Other situations may involve actual negligence or faulty procedures, such as when pharmacotherapists produce handwritten prescriptions for drugs. Adverse effects
A very common iatrogenic effect is caused by drug interaction, i.e., when pharmacotherapists fail to check for all medications a patient is taking and prescribe new ones that interact agonistically or antagonistically (thereby potentiating or attenuating the intended therapeutic effect). Such situations can cause significant morbidity and mortality. Adverse reactions, such as allergic reactions to drugs, even when unexpected by pharmacotherapists, are also classified as iatrogenic. The evolution of antibiotic resistance in bacteria is iatrogenic as well. Bacterial strains resistant to antibiotics have evolved in response to the over prescription of antibiotic drugs.Certain drugs are toxic in their own right in therapeutic doses because of their mechanism of action. Alkylating antineoplastic agents, for example, cause DNA damage, which is more harmful to cancer cells than regular cells.