Asplenia with cardiovascular anomalies, also known as Ivemark syndrome and right atrial isomerism, is an example of a

heterotaxy syndrome Situs ambiguus (), or heterotaxy, is a rare congenital defect in which the major visceral Organ (anatomy), organs are distributed abnormally within the chest and abdomen. Clinically, heterotaxy spectrum generally refers to any defect of left-righ ...

. These uncommon

congenital disorders A birth defect is an abnormal condition that is present at birth, regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities can range from mild to severe. Birth de ...

are characterized by defects in the heart, spleen and paired organs such as the lungs and kidneys. Another name is "asplenia-cardiovascular defect-heterotaxy". Right atrial isomerism is named for its discoverer, Swedish pathologist Biörn Ivemark.

Presentation

In right atrial isomerism, both atria of the heart are morphological right atria leading to associated abnormalities in the pulmonary venous system. In addition, individuals with right atrial isomerism develop

asplenia Asplenia is the absence of normal spleen function and is associated with some serious infection risks. Hyposplenism is the condition of reduced ('hypo-'), but not absent, splenic functioning. ''Functional'' asplenia occurs when splenic tissue is ...

, a midline liver, malrotation of the small intestine and the presence of two morphologic right lungs. Individuals with left atrial isomerism, by comparison, have two morphologic left atria,

polysplenia Polysplenia is a congenital disease manifested by multiple small accessory spleens, rather than a single, full-sized, normal spleen. Polysplenia sometimes occurs alone, but it is often accompanied by other developmental abnormalities. Conditions ...

, intestinal malrotation and two morphologic left lungs.

Causes

The cause of heterotaxy is unknown. The Ivemark Syndrome Association, which is based in

Dorset Dorset ( ; Archaism, archaically: Dorsetshire , ) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by Somerset to the north-west, Wiltshire to the north and the north-east, Hampshire to the east, t ...

, is one of the organisations dedicated to helping patients and funding research.

Presentation

Causes

Diagnosis

Treatment

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