The different types of intestinal atresia are named after their location:
- Duodenal atresia – malformation of the duodenum, part of the intestine that empties from the stomach
- Jejunal atresia – malformation of the jejunum, the second part of the intestine extending from the duodenum to the ileum, that causes the jejunum to block blood flow to the colon 
- Ileal atresia – malformation of the ileum, the lower part of the small intestine
- Colon atresia – malformation of the colon
An inherited form – familial multiple intestinal atresia – has also been described. This disorder was first reported in 1971. It is due to a mutation in the gene TTC7A on short arm of chromosome 2 (2p16). It is inherited as an autosomal recessive gene and is usually fatal in infancy.
The most common cause of non-duodenal intestinal atresia is a vascular accident in utero that leads to decreased intestinal perfusion and ischemia of the respective segment of bowel. This leads to narrowing, or in the most severe cases, complete obliteration of the intestinal lumen.
In the case that the superior mesenteric artery, or another major intestinal artery, is occluded, large segments of bowel can be entirely underdeveloped. Classically, the affected area of bowel assumes a spiral configuration and is described to have an "apple peel" like appearance; this is accompanied by lack of a dorsal mesentery. Ileal atresia can also result as a complication of meconium ileus.
Intestinal atresias are often discovered before birth: either during a routine sonogram which shows a dilated intestinal segment due to the blockage, or by the development of polyhydramnios (the buildup of too much amniotic fluid in the uterus). These abnormalities are indications that the fetus may have a bowel obstruction which a more detailed ultrasound study can confirm.
Some fetuses with bowel obstruction have abnormal chromosomes. An amniocentesis is recommended because it can determine not only the sex of the baby, but whether or not there is a problem with the chromosomes.
Fetal and neonatal intestinal atresia are treated using laparotomy after birth. If the area affected is small, the surgeon may be able to remove the damaged portion and join the intestine back together. In instances where the narrowing is longer, or the area is damaged and cannot be used for period of time, a temporary stoma may be placed.
- Jejunal Atresia. Genetic and Rare Diseases Information Center (GARD) https://rarediseases.info.nih.gov/diseases/6799/jejunal-atresia
- Le, Tao (2013). First Aid for the USMLE STEP. New York: Mc Graw Hill. p. 308. ISBN 978-0-07-180232-1.
- Mishalany HG, Der Kaloustian VM (1971) Familial multiple-level intestinal atresia: report of two siblings. J Pediat 79: 124