Colonoscopy and sigmoidoscopy are very similar investigations. Sigmoidoscopy allows visualisation of only the distal part of the colon while colonoscopy allows visualisation of the entire large bowel and the distal small bowel, as well. Both investigations involve passing a camera through the anus.
Anencephaly is a birth defect due to unknown causes in most situations. However, research shows that a deficiency of folic acid during early pregnancy can play a role in neural tube development. In addition, a family history of anencephaly increases the probability of the birth defect.o research the causes of Anencephaly, consider researching the causes of these these diseases that may be similar, or associated with Anencephaly: 1  Neural tube defect. 2  NTD. 3  Neural tube defect spectrum. 4  Absent cerebellum. 5  Absent cerebrum.
Many different types of brain defects are caused by improper closure of this neural tube. One such congenital brain anomaly, anencephaly (literally without brain) results when the topmost portion of the tube fails to close and the brain does not develop.Anencephaly is the most common severe malformation seen in stillborn births. It is about four times more common in females than males.ongenital brain defects may have genetic, infectious, toxic, or traumatic causes. In most cases, no certain cause can be identified. GENETIC CAUSES Some brain defects are caused by trisomy, the inclusion of a third copy of a chromosome normally occurring in pairs.