One of the families was consanguineous.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 sequencing 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 researchers found two different GREB1L mutations, each being unique to their respective pedigrees. In total, there were 23 individuals analyzed between the two families, four of which had BRA and five of which had URA. GREB1L mutations were identified in all of the affected individuals as well as in three unaffected family members, demonstrating incomplete penetrance and variable expressivity.There are several hundred to perhaps several thousand genes that, if they had the right kind of mutation, could lead to renal agenesis in humans. It is possible that each individual or family experiencing renal agenesis has a unique gene or genetic mutation causing the condition due to the fact that there are so many genes that are critical to proper renal development.Chromosomal anomalies have been associated with BRA in certain cases (chromosomes 1, 2, 5 and 21), but these anomalies were not inherited and have not been observed in subsequent cases. Additionally, neither extreme substance abuse or environmental factors (high power line, mercury, ground water issues, etc.) have been reported to be linked to an increased incidence of BRA or other cause of Potter sequence.
Treatment
There is no known permanent cure or treatment for primary trimethylaminuria, only mitigation of the effects. For secondary trimethylaminuria, it depends on the cause; for precursor overload, reducing the intake of TMA and its precursors will end symptoms. For TMAU caused by hypothetical gut dysbiosis, clinical review by a doctor, a plant based diet and reduced precursor intake should return gut flora to a healthy state.Primary TMAU sufferers generally have some residual FMO3 activity in the liver which processes TMA, however this happens relatively slowly. According to a study by Al-Waiz M TMA filters through to the bladder at half the rate of TMAO, and a healthy functioning person passes 99% of TMAO in urine within 24 hours. Therefore its estimated that the majority of TMA would be filtered out within 48 hours if no additional TMA or precursor is ingested, regardless of liver function. The metabolic and clinical manifestations of TMAU are generally regarded as benign, as there is no associated organ dysfunction. This designation, and the fact that the condition is often unrecognised by doctors, misdiagnosed and can have important ramifications including missed or delayed diagnosis.Affected individuals experience shame and embarrassment, fail to maintain relationships, avoid contact with people who comment on their condition, and are obsessive about masking the odour with hygiene products and even smoking. The malodorous aspect can have serious and destructive effects on schooling, personal life, career and relationships, resulting in social isolation, low self-esteem, depression, paranoid behaviour, and suicide.