An imperforate anus or anorectal malformations (ARMs) are birth defects in which the rectum is malformed. ARMs are a spectrum of different congenital anomalies which vary from fairly minor lesions to complex anomalies.[1] The cause of ARMs is unknown; the genetic basis of these anomalies is very complex because of their anatomical variability. In 8% of patients, genetic factors are clearly associated with ARMs.[2]Anorectal malformation in Currarino syndrome represents the only association for which the gene HLXB9 has been identified.[clarification needed][1][3]
^Moore, Samuel W (14 November 2006). "Genetics, Pathogenesis and Epidemiology of Anorectal Malformations and Caudal Regression Syndrome". In Holschneider, Alexander Matthias; Hutson, John M. (eds.). Anorectal Malformations in Children. Springer. pp. 31–48. doi:10.1007/978-3-540-31751-7_3. ISBN978-3-540-31750-0.