Right Atrial Isomerism (RAI)

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OMIM®: ⁵⁷ Right atrial isomerism (RAI) is a severe complex congenital heart defect resulting from embryonic disruption of proper left-right axis determination. RAI is usually characterized by complete atrioventricular septal defect with a common atrium and univentricular AV connection, total anomalous pulmonary drainage, and transposition or malposition of the great arteries. Affected individuals present at birth with severe cardiac failure. Other associated abnormalities include bilateral trilobed lungs, midline liver, and asplenia, as well as situs inversus affecting other organs. Left atrial isomerism (LAI) is a related disorder with a somewhat better prognosis. LAI is characterized by bilateral superior vena cava, interruption of the intrahepatic portion of the inferior vena cava, partial anomalous pulmonary venous drainage, and ventricular septal defect. Patients with LAI may have polysplenia and bilateral bilobed lungs, as well as situs inversus affecting other organs. Both RAI and LAI malformation complexes have classically been referred to as Ivemark syndrome (summary by Eronen et al., 2004 and Kaasinen et al., 2010). (208530) (Updated 08-Dec-2022)

MalaCards based summary: Right Atrial Isomerism, also known as ivemark syndrome, is related to heart septal defect and congenital heart defects, multiple types, 6. An important gene associated with Right Atrial Isomerism is GDF1 (Growth Differentiation Factor 1), and among its related pathways/superpathways are Nervous system development and Beta-2 adrenergic-dependent CFTR expression. The drugs Lactitol and Complement System Proteins have been mentioned in the context of this disorder. Affiliated tissues include spleen, heart and liver, and related phenotypes are inguinal hernia and tetralogy of fallot

Orphanet: ⁵⁸ A rare heterotaxia characterized by complex congenital heart malformations and abnormal lateralization of other thoracic and abdominal organs due to embryonic disruption of the left-right axis development. Cardiac defects include dextrocardia or mesocardia, common atrioventricular valve associated with complete atrioventricular septal defect or common atrium, transposition or malposition of the great arteries, and total anomalous pulmonary venous drainage, among others. Cardiac arrhythmias are frequently observed. Typical abnormalities of other organs are bilateral trilobed lungs, midline liver, and asplenia. Patients present in the newborn period with severe cardiac failure and cyanosis. Prognosis is poor.

GARD: ¹⁹ Ivemark syndrome is a rare congenital condition that affects multiple organ systems of the body. Ivemark syndrome is classified as a heterotaxy disorder or a laterality disorder. These terms refer to the failure of the internal organs of the chest and abdomen to be arranged in the proper location within the body. It is characterized by the absence (asplenia) or underdevelopment (hypoplasia) of the spleen, heart malformations, and the abnormal arrangement of the internal organs of the chest and abdomen. The exact cause of Ivemark syndrome is not known. Most cases are sporadic (isolated and seemingly random). Unlike some other heterotaxy disorders, causative gene genetic changes have not been identified.

UniProtKB/Swiss-Prot: ⁷³ A severe complex congenital heart defect resulting from embryonic disruption of proper left-right axis determination. RAI is usually characterized by complete atrioventricular septal defect with a common atrium and univentricular AV connection, total anomalous pulmonary drainage, and transposition or malposition of the great arteries. Affected individuals present at birth with severe cardiac failure. Other associated abnormalities include bilateral trilobed lungs, midline liver, and asplenia, as well as situs inversus affecting other organs.

Disease Ontology: ¹¹ A visceral heterotaxy that is characterized by complete atrioventricular septal defect with a common atrium and univentricular AV connection, total anomalous pulmonary drainage, and transposition or malposition of the great arteries and that has material basis in homozygous mutation in the GDF1 gene on chromosome 19p12.

Wikipedia ⁷⁵ Asplenia: Asplenia refers to the absence of normal spleen function and is associated with some serious infection... more...

Ivemark syndrome: Asplenia with cardiovascular anomalies, also known as Ivemark syndrome and right atrial isomerism, is an... more...

Clinical features from OMIM®:

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