Heterotaxy Syndrome

What is Heterotaxy Syndrome?

Heterotaxy syndrome is a birth defect that is very rare involving the heart as well as other organs. In this syndrome, organs that are paired, for instance the kidneys or lungs, are frequently mirror images of each other rather than having the unique features of left and right that are classically present.

There are forms of heterotaxy that are different. All normally involve defects of the heart, of varying severity and type. Additionally, organs such as the intestines, stomach, lungs and liver can be in abnormal positions in the chest as well as the abdomen.

The intestines can develop malrotation, which causes loops of bowel to be lined up erroneously. With this situation, the bowel often twists on itself – referred to as volvulus – so numerous children with this situation need surgery of the abdominal area to fix this. Some children with syndrome can have a serious disorder of the liver referred to as biliary atresia. This can also need surgical intervention. There can also be anomalies with the central nervous system, urinary tract as well as skeleton.

Also the spleen might not be able to work correctly or in some cases can be entirely missing. This may create numerous problems, since the spleen aids the body in fighting infections. When the spleen is not there or does not function correctly, patients have a more problematic time recuperating from surgeries or infections. Individuals with Heterotaxy can require numerous surgeries. In some circumstances, there can be a spleen that is functioning, but it might be divided into several smaller spleens – condition referred to as polysplenia.

Children with Heterotaxy sometimes have dextrocardia. This occurs when the heart is located in the right chest rather than the left chest.

Here are broad descriptions of two kinds of Heterotaxy. The structure of the heart varies from child to child. Types of Heterotaxy include:

Asplenia (Right Atrial Isomerism)

Those children having this disorder have numerous defects of the heart. They can have septal flaws which are holes amid the tissues that divide the two sides of the heart along with heart valve problems, especially the pulmonary one. They can also have anomalies of blood that is coming from the lungs and going to the heart – “anomalous pulmonary venous connection”. There might be an absent spleen – asplenia – and the liver as well as other organs can be located on the incorrect body side.

Polysplenia (Left Atrial Isomerism)

Those children with this disorder might have septal flaws – holes between the tissues dividing the two sides of the heart – as well as difficulties with heart valves and the electrical system. Some of these children with this disorder have total heart block that occurs when the electrical system in the upper-chamber does not interconnect with the electrical system of the lower-chamber. Many children need pacemakers for this situation. The spleen cannot exist, or there can be several small spleens – polysplenia – rather than only one spleen.

What do these terms “left atrial isomerism” and “right atrial isomerism” mean? The heart possesses small pockets, one for each of two upper chambers, referred to as atrial appendages. Within a normal heart, the right atrial appendage is visually different from the left. With Heterotaxy, these two appendages look alike. “Isomerism” refers to mirror images – therefore the terms “left atrial isomerism” and “right atrial isomerism”.


The symptoms of this syndrome widely vary. In nearly every case of “right atrial isomerism” and a few of “left atrial isomerism”, indications will develop after birth or in several days or weeks after birth since these defects of the heart are severe. With these cases, the symptoms include:

  • Purple or blue tint to the lips, nails or skin – known as cyanosis
  • Breathing difficulties
  • Feeding difficulties
  • Lethargy – baby is abnormally unresponsive or sleep

Often individuals with “left atrial isomerism” do not have any symptoms and the effect is not diagnosed until the baby is older or can even be an adult.



The precise cause of this syndrome is not fully realized but the causes of the defects are believed to be caused by the way that the inner organs turn into position during fetal developing. This rotation could be caused by many different aspects including:

  • Genetics
  • Infection
  • Exposures to definite chemicals

There are some reports of families where numerous members have Heterotaxy syndrome but the exact reason this developed in these families has not been identified.

Recent investigative studies have also shown that this syndrome could be cause by mutations in ZIC3 and ACVR2B genes as possible cause of Heterotaxy and associated cardiovascular anomalies.

The etiology is really poorly assumed but it is believed to also be linked to:

  • Family history of malformations
  • Maternal diabetes mellitus
  • Maternal cocaine use

This would seem to suggest that both environmental factors as well as genetic mutations play a part in this syndrome developing.


Individuals born with Heterotaxy syndrome as well as heart disease will of course need medications to aid in preventing heart failure as well as surgery to correct any abnormalities that may be life threatening. The type of heart surgery performed is based on the child’s specific heart defect.

Those children with Heterotaxy also have an amplified peril of having electrical signs in the heart tissue working irregularly and might need to have a pacemaker later in life. If the child’s intestines are incorrectly twisted, surgery will also be required to replace the intestines into their correct positions so as to avoid any obstruction.

When biliary atresia is involved, a liver transplant is frequently needed. If the spleen is not functioning properly, children will be required to take antibiotics daily and receive different vaccinations so as to protect them from definite types of infections.


With no corrective surgery, the majority of children with this syndrome as well as significant heart problems will not survive beyond the 1st year of life. If the child does not have numerous organs involved, then it is possible that they can have a normal life. Even after surgery, most of these children face numerous challenges based on their exact anatomy.

Life Expectancy

It is not known what the life expectancy is of a child with this syndrome because there are no statistics on life expectancy. Up until 10 years ago, no one lived more than 6 months.

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