Vaginal atresia

Vaginal atresia is a condition in which the vagina is abnormally closed or absent. The main causes can either be complete vaginal hypoplasia, or a vaginal obstruction, often caused by an imperforate hymen or, less commonly, a transverse vaginal septum. It results in uterovaginal outflow tract obstruction. This condition does not usually occur by itself within an individual, but coupled with other developmental disorders within the female. The disorders that are usually coupled with a female who has vaginal atresia are Rokitansky-Mayer- Küster-Hauser syndrome, Bardet-Biedl syndrome, or Fraser syndrome. One out of every 5,000 women have this abnormality. Vaginal atresia is a condition in which the vagina is abnormally closed or absent. The main causes can either be complete vaginal hypoplasia, or a vaginal obstruction, often caused by an imperforate hymen or, less commonly, a transverse vaginal septum. It results in uterovaginal outflow tract obstruction. This condition does not usually occur by itself within an individual, but coupled with other developmental disorders within the female. The disorders that are usually coupled with a female who has vaginal atresia are Rokitansky-Mayer- Küster-Hauser syndrome, Bardet-Biedl syndrome, or Fraser syndrome. One out of every 5,000 women have this abnormality. The exact mechanism for vaginal atresia is not well known, as specific molecular mechanisms which lead to the closing or absence of the vagina are unclear. There are various pathways that may support or restrict regular vaginal development. Research has shown that changing factors may also include paracrine and autocrine signals and changes in the basis of developing organs. Specific patterns of genetic transmission have not been identified for this condition. Normal reproductive organ production requires timely coordination of the following systems: external genitalia, internal ductal system, and gonadal structure. The abnormal development of the vagina results in an incomplete unit (low, mid, high transverse septum), failure of epithelium degeneration (imperforate hymen), and vaginal atresia. According to a number of medical professionals, timely coordination of interdependent systems is required for normal reproductive organ development in both males and females. The description of vaginal atresia mechanism can be explained in several steps of development of the uterovaginal canal per the information provide by these medical professionals. These interdependent systems are external genitalia, gonadal structures, and internal ductal system. The absence of androgens, müllerian-inhibiting substance (MIS), and testes causes the continuous differentiation of the müllerian ducts with reversion of the wolffian ducts in the female embryo. The müllerian duct will then elongate to reach the urogenital sinus within 9 weeks of gestation; this forms the uterovaginal canal. By 15–26 weeks' of gestation, cephalic growth of the sinovaginal bulb is completed. The vaginal plate is also formed from the fusion of vaginal cord with the sinovaginal bulb. The formation of the uterovaginal canal is thought to occur from the caudal to the cephalic portion, all while the urogenital sinus is used to Crete the epithelial lining. Development of the vagina is completed by the fifth month of gestation. While the mesenchyme that surrounds the structures transitions into musculature of the genital tract, the fallopian tubes are formed via the cephalic remnants of the müllerian duct. This developmental process attributes to the process of how proper vaginal development takes place. Failure of the septum to regress between the fused müllerian ducts results in a septate uterus. The incomplete fusion of the müllerian ducts attributes to the formation of arcuate, bicornuate, or didelphid uteri. Females who have both Rokitansky-Mayer-Küster-Hauser syndrome and uterovaginal atresia are theorized to have a failing caudal development within the müllerian ducts. Variations of transverse vaginal septum might be described by the malfunctions at the level of the vaginal plate. Though the müllerian and urogenital sinuses play a huge role in the derivation of the vagina, it is unclear how much of a role each of these play normal vaginal development. Symptoms and signs in the newborn can be sepsis, abdominal mass, and respiratory distress. Other abdominopelvic or perineal congenital anomalies frequently prompt radiographic evaluation in the newborn, resulting in a diagnosis of coincident vaginal atresia. Symptoms for vaginal atresia include cyclical abdominal pain, the inability to start having menstrual cycles, a small pouch or dimple where a vaginal opening should be, and pelvic mass when the upper vagina becomes filled with menstrual blood. Signs and symptoms of vaginal atresia or vaginal agenesis can often go unnoticed in females until they reach the age of menstruation. Women may also experience some form of abdominal pain or cramping. Vaginal atresia can sometimes be diagnosed by physical examination soon after birth. A child with vaginal atresia often has other congenital abnormalities and other tests such as x-ray and tests to evaluate the kidney are done. Findings in adolescents may include abdominal pain, difficulty voiding, and backache, but most present with amenorrhea. Difficulties with sexual intercourse can suggest atresia. In the event that the condition is not caught shortly after birth, vaginal atresia becomes more evident when no menstrual cycle is occurs. If vaginal atresia is suspected by the doctor, a blood test may also be request for any of the previously mentioned syndromes, a magnetic resonance imaging (MRI) test, or an ultrasound. A regular evaluation of children born with an imperforate anus or anorectal malformation should be paired with the assessment of the results from these tests. The cause for vaginal atresia is unknown. Typically, the creation of the vaginal canal is completed within the fetus by the 20th week of gestation. Researchers believe in patients with vaginal atresia, tubes known as the Müllerian ducts don't develop correctly within the first 20 weeks of gestation/pregnancy. Typically, one of these ducts develops in the fallopian tubes while the other ducts develop into the vagina and uterus. Vaginal atresia is found to occur when the urogenital sinus does not contribute to the formation of the lower portion of the vagina. As previously mentioned, there are other disorders or syndromes that are found in conjunction with individuals living with vaginal atresia. These disorders are: Rokitansky-Mayer-Küster-Hauser syndrome is a disorder in females that causes the uterus and vagina to be absent or underdeveloped. Those born with this disorder are considered to be genetic female and have a 46XX chromosomes. Kidney anomalies often accompany this disorder as well. Also referred to as Müllerian agenesis, vaginal agenesis, or müllerian aplasia, this disorder affects 1 in every 4,000-5,000 females. A cloacal malformation often accompanies this disorder, which is the surgical treatment that incorporates several vaginal replacement techniques. This disorder is caused by an implication in the WNT4 protein coding gene, which is found on the short arm (p) of chromosome 1. A genetic mutation occurs causing a substitution of leucine to proline residue at position 12 on the amino acid in the WNT4 protein. Essentially, this will cause a reduction in the intranuclear levels of β catenin. Additionally, the inhibition of steroidogenic enzymes such as 17α-hydroxylase and 3β-hydroxysteriod dehydrogenase because of this mutation, which leads to an excess amount to androgen in the system. As WNT4 gene is essential for developing a protein that is essential for female sex development, the Müllerian duct is either absent or deformed when this gene is not present. The development of the female reproductive system may be disrupted in the absence of the WNT4 protein's regulation. Abnormal androgen production is also induced, eventually leading to hyperandrogenism and Müllerian aplasia.