When mutations prevent the formation of 345 type IV collagen network in the glomerulus, the 112 network, which is formed in fetal development but usually replaced by 345, persists into adult life. Inheritance patterns
Alport syndrome can have different inheritance patterns depending on which specific mutation is present. In most people with Alport syndrome (about 85%), the condition is inherited in an X-linked pattern, due to mutations in the COL4A5 gene. A condition is considered X-linked if the gene involved in the disorder is located on the X chromosome. In males, who have only one X chromosome, one altered copy of the COL4A5 gene is sufficient to cause severe Alport syndrome, explaining why most affected males eventually develop kidney failure. In females, who have two X chromosomes, a mutation in one copy of the COL4A5 gene usually results in blood in the urine, but most affected females do not develop kidney failure. Alport syndrome can also be inherited in an autosomal recessive pattern if both copies of the COL4A3 or COL4A4 gene, located on chromosome 2, have been mutated. Most often, the parents of a child with an autosomal recessive disorder are not affected but are carriers of one copy of the altered gene. Past descriptions of an autosomal dominant form are now usually categorized as other conditions. Notably, conditions associated with giant platelets and associated with mutations of MYH9 are no longer considered to be Alport variants.
Vaginal tearing can occur in rape victims because those two things will not occur. This is consistent with the fact that more injuries result from sexual assault than from consensual intercourse. An inability to produce adequate vaginal lubrication and dilatation is thought to be an underlying cause of severe tears in the upper area of the vagina. Types of vaginal trauma
Intercourse-related lacerations can range from superficial tears to more severe lacerations, tears rarely extend into the rectal lumen and the peritoneal cavity. Recto-vaginal injuries are usually a result of assault with a foreign object, rape, or accidental gynecologic injury. Injuries of this severity that resulted from consensual sex are very rare. Posterior and right vaginal fornix lacerations have been known to occur during consensual vaginal intercourse. The location of these lacerations is usually based on a womans reproductive anatomy. It is common for women to have a uterus that lies slightly to the right, this exposes the right fornix and makes it easier for some type of tearing or trauma to occur. Lacerations to the posterior peri-cervical vagina tend to occur in the missionary position, hips and legs hyperflexed. Other positions can also expose the posterior vaginal wall that usually protected by the cervix, this allows for posterior fornix tears. Tears in the upper area of the vagina are more often reported in consensual intercourse than forced intercourse. Complications from severe vaginal lacerations, such as from an assault, can include hemoperitoneum, pneumoperitoneum, and retroperitoneal hematoma with or without vaginal perforation.