In 1997, a patient was identified who carried a rare balanced chromosomal translocation involving chromosome 19 and the X chromosome. This suggested that the affected gene might lie in one of the two regions that were disrupted by this cytogenetic anomaly. Linkage analysis in affected families also implicated this region in disease, and led to the cloning of the first DBA gene. About 20–25% of DBA cases are caused by mutations in the ribosome protein S19 (RPS19) gene on chromosome 19 at cytogenetic position 19q13.2. Some previously undiagnosed relatives of DBA patients were found to carry mutations, and also had increased adenosine deaminase levels in their red blood cells, but had no other overt signs of disease.A subsequent study of families with no evidence of RPS19 mutations determined that 18 of 38 families showed evidence for involvement of an unknown gene on chromosome 8 at 8p23.3-8p22. The precise genetic defect in these families has not yet been delineated. Malformations are seen more frequently with DBA6 RPL5 and DBA7 RPL11 mutations.The genetic abnormalities underpinning the combination of DBA with Treacher Collins syndrome (TCS)/mandibulofacial dysostosis (MFD) phenotypes are heterogeneous, including RPS26 (the known DBA10 gene), TSR2 which encodes a direct binding partner of RPS26, and RPS28. Molecular basis
The phenotype of DBA patients suggests a hematological stem cell defect specifically affecting the erythroid progenitor population. Loss of ribosomal function might be predicted to affect translation and protein biosynthesis broadly and impact many tissues.
In gynecology, a rectocele ( REK-tə-seel) or posterior vaginal wall prolapse results when the rectum bulges (herniates) into the vagina. Two common causes of this defect are childbirth and hysterectomy. Rectocele also tends to occur with other forms of pelvic organ prolapse, such as enterocele, sigmoidocele and cystocele.Although the term applies most often to this condition in females, males can also develop it. Rectoceles in men are uncommon, and associated with prostatectomy. Signs and symptoms
Mild cases may simply produce a sense of pressure or protrusion within the vagina, and the occasional feeling that the rectum has not been completely emptied after a bowel movement. Moderate cases may involve difficulty passing stool (because the attempt to evacuate pushes the stool into the rectocele instead of out through the anus), discomfort or pain during evacuation or intercourse, constipation, and a general sensation that something is "falling down" or "falling out" within the pelvis. Severe cases may cause vaginal bleeding, intermittent fecal incontinence, or even the prolapse of the bulge through the mouth of the vagina, or rectal prolapse through the anus. Digital evacuation, or, manual pushing, on the posterior wall of the vagina helps to aid in bowel movement in a majority of cases of rectocele. Rectocele can be a cause of symptoms of obstructed defecation. Causes
Rectoceles result from the weakening of the pelvic floor also called pelvic organ prolapse. Weakened pelvic structures occur as a result of an episiotomy during previous births, even decades later.