Intestinal malrotation is a congenital anomaly of rotation of the midgut. It occurs during the first trimester as the fetal gut undergoes a complex series of growth and development. Malrotation can lead to a dangerous complication called volvulus. Malrotation can refer to a spectrum of abnormal intestinal positioning, often including:
The small intestine found predominantly on the right side of the abdomen
The cecum displaced from its usual position in the right lower quadrant into the epigastrium or right hypochondrium
An absent or displaced ligament of Treitz
Fibrous peritoneal bands called bands of Ladd running across the vertical portion of the duodenum
An unusually narrow, stalk-like mesenteryThe position of the intestines, narrow mesentery and Ladds bands can contribute to several severe gastrointestinal conditions. The narrow mesentery predisposes some cases of malrotation to midgut volvulus, a twisting of the entire small bowel that can obstruct the mesenteric blood vessels leading to intestinal ischemia, necrosis, and death if not promptly treated. The fibrous Ladds bands can constrict the duodenum, leading to intestinal obstruction. Signs and symptoms
Signs and symptoms of malrotation vary depending on if the patient is suffering from an acute volvulus or experiencing chronic symptoms. If the patient, most often an infant, presents acutely with midgut volvulus, it is usually manifested by bilious vomiting, crampy abdominal pain, abdominal distention, and in late cases, the passage of blood and mucus in their stools. Patients with chronic, uncorrected or undiagnosed malrotation can have recurrent abdominal pain and vomiting. Malrotation may be asymptomatic.
Newborns may present with profound hypotonia (low muscle tone), seizures, apnea, and an inability to eat. Cause
Zellweger syndrome is an autosomal recessive disorder caused by mutations in genes that encode peroxins, proteins required for the normal assembly of peroxisomes. Most commonly, patients have mutations in the PEX1, PEX2, PEX3, PEX5, PEX6, PEX10, PEX12, PEX13, PEX14, PEX16, PEX19, or PEX26 genes. In almost all cases, patients have mutations that inactivate or greatly reduce the activity of both the maternal and paternal copies of one these aforementioned PEX genes.As a result of impaired peroxisome function, an individuals tissues and cells can accumulate very long chain fatty acids (VLCFA) and branched chain fatty acids (BCFA) that are normally degraded in peroxisomes. The accumulation of these lipids can impair the normal function of multiple organ systems, as discussed above. In addition, these individuals can show deficient levels of plasmalogens, ether-phospholipids that are especially important for brain and lung function. Diagnosis
In addition to genetic tests involving the sequencing of PEX genes, biochemical tests have proven highly effective for the diagnosis of Zellweger syndrome and other peroxisomal disorders. Typically, Zellweger syndrome patients show elevated very long chain fatty acids in their blood plasma. Cultured primarily skin fibroblasts obtained from patients show elevated very long chain fatty acids, impaired very long chain fatty acid beta-oxidation, phytanic acid alpha-oxidation, pristanic acid alpha-oxidation, and plasmalogen biosynthesis.