Heterotaxy Explained

Heterotaxy Explained

Heterotaxia is characterized by an inverted arrangement of body organs in the abdomen. The symptoms of this disorder are quite different depending on the location of the organs and range from asymptomatic to severe life-threatening heart defects.

What is heterotaxy?

Heterotaxy is not an independent disease, but represents a symptom complex of certain underlying genetic disorders. The word heterotaxy was derived from the Greek and means “different arrangement”. This term therefore describes the different arrangement of body organs.

This is the relocation of all or certain body organs from the right to the left side of the body or vice versa. This is referred to as a lateralization defect. A completely mirror-inverted distribution of the organs is also referred to as situs inversus.

However, this condition does not cause any physical problems and remains asymptomatic. However, severe health impairments are to be expected if organs are partially relocated. In these cases, in addition to serious heart defects, there are also anomalies in the bile ducts or kidneys. Serious midline defects are usually found.

Therapy for heterotaxia depends on which organ defects are present. A complete replacement of the organs in the context of a situs inversus does not require any treatment because no disturbances occur. Regardless of its severity, heterotaxia is a very rare disorder. Only one in 15,000 people is affected by this anomaly.

Causes

What all heterotaxies have in common is the fact that these disorders are all genetic. They usually represent a symptom or a symptom complex of certain genetic diseases. Various genes that are important for the left-right orientation of the body’s organs during embryonic development can be responsible for the development of heterotaxy.

These genes include ACVR2B, LEFTY A, CFC1 or ZIC3. Autosomal recessive, autosomal dominant and x-linked inheritance is found. Autosomal recessive inheritance is the most common. An autosomal dominant inheritance is rarer and an x-chromosomal transmission occurs very rarely.

In autosomal recessive inheritance, both parents must be carriers of the defective gene. The offspring will only become ill if they receive the mutated genes of both parents. This is the case for 25 percent of families at risk. Only one gene is affected in three percent of heterotaxies, with autosomal dominant inheritance.

Either the mutation occurs spontaneously or 50 percent of the defective gene is passed from an affected parent to the child. Despite having the same genetic cause, the degree of heterotaxy can be completely different within the affected families.

Symptoms, Ailments & Signs

As already mentioned, heterotaxy is characterized by the displacement of body organs from left to right or vice versa. This can lead to a complete exchange of all organs on the other side of the body. In this case, there are no symptoms, since all organs maintain their usual environment.

However, if only individual organs change sides of the body, serious health problems often occur. In most cases, there are various heart defects that result from a so-called transposition of the large arteries or a double outlet right ventricle. When the great arteries are transposed, major cardiac vessels are interchanged.

It occurs during embryogenesis due to a disrupted rotation of the heart’s outflow tract. In a double outlet right ventricle, the pulmonary artery and aorta arise exclusively from the right ventricle of the heart. Sometimes the heart defect is also associated with the absence of the spleen ( asplenia ).

In asplenia, the entire body has only the properties of the right side of the body. Conversely, if the organism only has characteristics of the left half of the body, polysplenia is always present. Polysplenia refers to the presence of many small spleens.

Arhinencephaly (absence of the olfactory bulb), clefts in the spine, cleft palate, malformations of the anus and coccyx, and urinary tract anomalies are often observed in midline defects, which are often x-linked. A special disease is the so-called Kartagener syndrome.

This genetic disease is characterized by three sets of symptoms: situs inversus, bronchial bulges ( bronchiectasis ) and chronic sinusitis. Only the occurrence of situs inversus (complete swapping of the organs) gives an indication of the genetic cause of the respiratory problems. If this symptom is absent, the disease is PCD, which is much more difficult to diagnose.

Diagnosis & disease progression

Heterotaxia is diagnosed using imaging techniques. In the special case of x-chromosomal inheritance, the gene defect in the ZIC3 gene can also be detected. Prenatal examinations for heterotaxy in the case of familial accumulation are also possible.

Complications

Heterotaxy leads to a wrong arrangement of the organs in the patient’s body. However, the symptoms and complications depend on the exact arrangement of the internal organs, so that no general prediction is possible in this case. However, there are usually serious complications that can be life-threatening for those affected.

As a rule, those affected suffer from a heart defect, which in the worst case can lead to death. There may also be discomfort and pain in the spleen. It is not uncommon for patients to suffer from the so-called cleft palate and respiratory problems. This can lead to gasping, which in many cases leads to a panic attack. The quality of life of those affected is extremely limited by the heterotaxy.

Furthermore, the treatment is not necessary if the organs have been completely replaced. This does not result in a reduced life expectancy or other complaints. If there are malformations in the organs, surgical interventions may have to be carried out to solve them.

When should you go to the doctor?

Heterotaxia does not necessarily require a doctor’s visit. If there are no symptoms and the patient does not experience any impairments in everyday life, no doctor is needed. In some cases, heterotaxy may not result in treatment for life. However, if the sufferer suffers from heart problems, there is cause for concern. If you experience tachycardia, high blood pressure or a feeling of pressure in your chest, you should see a doctor.

In the event of sleep disorders, sweating, inner restlessness or circulatory disorders, further examinations should be initiated. If pain sets in, dizziness, a general feeling of illness or malaise, a doctor should be consulted. If the symptoms increase or spread, you should always consult a doctor. If the general level of performance drops, if there are problems with concentration or attention deficits, a doctor is needed. Breathing problems, the development of an anxiety disorder or panic attacks require a medical examination and therapy.

If they are not used, there will be a further deterioration in health and a significant impairment in the quality of life. If you have problems with your spleen or repeated digestive problems, you should consult a doctor. Heterotaxy can lead to a life-threatening condition. Therefore, a doctor’s visit must be initiated immediately as soon as the person concerned suffers from functional disorders or notices a sudden change in his state of health.

Treatment & Therapy

Heterotaxy cannot be treated causally because it is a genetic disorder. Therapy is often not necessary either, especially in the case of a situs inversus, because no symptoms occur when the organs are completely replaced.

Only the organs are arranged in reverse. If the organs are affected by serious malformations, they must of course be subjected to specific therapy. However, the actual lateralization defect, i.e. the displacement of the organs, does not have to be treated.

Outlook & Forecast

The prognosis of heterotaxia is very different and is made according to the individual specifications of the patient. In principle, the order of the organs in the body created during the development process cannot be completely changed afterwards. Treatment is symptomatic. The further course and the prospect of alleviating the symptoms are assessed accordingly.

There are a large number of patients who, despite heterotaxia, are free of impairments throughout their lives and do not feel any restrictions in their quality of life in everyday life. Those affected receive a favorable prognosis, although regular check-ups are necessary in order to document the general state of health and possible changes at an early stage.

In people who only have a few anatomical displacements of the organs or vessels, the good prognosis usually worsens. The transposition of large blood and heart vessels can be life-threatening for the patient and, in severe cases, lead to a reduction in overall life expectancy. If clefts occur, in most cases surgical interventions and corrections are necessary. It is not possible to give a general prognosis, as complications and sequelae can occur.

If there are respiratory problems, there is a risk of mental illnesses in addition to physical limitations. Anxiety, depression and behavioral problems can further worsen the prognosis. Some patients need help for life.

Prevention

Prevention of heterotaxy is not possible due to its genetic cause. However, if heterotaxy occurs in the family, prenatal examinations for a lateralization disorder are always carried out using sonography. Human genetic counseling can also be used in familial cases in order to assess the risk for the offspring.

Aftercare

In the case of heterotaxia, the affected person usually has very few or even no aftercare measures available. Those affected by this disease are primarily dependent on a quick and, above all, early diagnosis, so that there are no further complications and no further deterioration of the symptoms. Therefore, in the case of heterotaxy, the focus is on early detection with subsequent treatment.

In the worst case, however, this disease can cause death if the internal organs are affected by the disease. Self-healing cannot occur in this case either. Since it is a genetic disease, it cannot be completely cured. If the person concerned wishes to have children, genetic counseling can be useful to prevent further inheritance of heterotaxy.

In some cases, the deformities in the organs can be corrected. After such a surgical procedure, however, the person concerned should always rest and protect his body. Efforts or stressful activities should be avoided. The life expectancy of those affected is significantly reduced by heterotaxy.

You can do that yourself

Since heterotaxy is a genetic disorder, treatment is usually purely symptomatic. In some cases, no treatment is necessary at all because no serious symptoms occur.

People who suffer from heterotaxia should have regular medical examinations so that any health problems can be identified quickly and treated if necessary. If complications arise, a doctor’s visit is required. The most important self-help measure is to pay attention to the body’s signals and to document any abnormalities. If an operation is necessary, the instructions of the doctor responsible must be followed. The affected person must take it easy before and after the procedure and should follow a suitable diet without stimulants.

Depending on which organ needs to be surgically relocated, further measures can be taken. When performing an operation on the liver, care must be taken to protect the right upper abdomen. The surgical wound must be well cared for so that scars and wound healing disorders do not occur. Comprehensive aftercare is always required after an intervention on the internal organs.

Heterotaxy