Situs ambiguus

A heterotaxy (Greek heteros, different ', taxis, arrangement ') describes a shift of the organs in the chest or abdomen from the right to the left side or vice versa. Such malformations are also called lateralization defect. Since there are many possibilities of such a right / left - exchange, it is characteristic of various diseases. A complete exchange is called situs inversus ( totalis ) and actually makes no problems. If only a part of the organs to the opposite side or in the sense of a situs ambiguus shifted to the midline, usually appear too different heart defects, malformations of the kidney and biliary tract, or so-called midline defects. All Straight Taxien taken together occur about one in every 15,000 people.

Cause

Although on the exact cause of this disorder is still not well known, different genes have now been identified, including ZIC3, ACVR2B, LEFTY A and CFC1, which play a role in left-right orientation in the embryonic development. However, heterozygous mutations in these genes cause only about 3% of all hetero Taxien. The severity of malformations within affected families is very different. Among the hereditary variants of the Straight Taxien an autosomal recessive, more rarely, an autosomal dominant and least frequently an X-linked pattern of inheritance were found most frequently. The latter are caused by the ZIC3 - gene located on the X chromosome.

Symptoms

Frequent heart failure caused by a disturbed rotation of the outflow tract in the development of the heart in the context of heterotaxy, is a transposition of the great arteries or double outlet right ventricle. Is the heart defects associated with the absence of the spleen ( asplenia ), one also speaks of Ivemark symptom complex, named after the discoverer and describer Björn Ivemark. A asplenia is seen as a lateralization defect in which the whole organism properties of the right half of the body has (right isomerism ). Just as often, there are many small spleens ( polysplenia ), with reversion, the whole body is to have the property of the left half of the body (left isomerism ). Because even paired organs are never completely symmetrical, even lungs, kidneys or adrenal glands can be affected by the symmetry is reversed or missing. Midline defects are found especially in the X-linked inherited mutations in the gene ZIC3 in the form of absence of the olfactory bulb ( arhinencephaly ), myelomeningocele, cleft palate, urinary tract anomalies and malformations of the coccygeal vertebrae and the anus.

Swell

• Malformation