Clinical Presentation and Therapy of Anomalies of the Situs.

Situs abnormalities may occur in many and most often more complex congenital cardiac malformations. These conditions are collectively referred to as heterotaxy syndromes, derived from the Greek words "heteros" meaning different and "taxos" meaning orientation or arrangement. Clinically, heterotaxy spectrum encompasses defects in the left-right laterality and arrangement of visceral organs. "Situs" is derived from Latin and is the place where something exists or originates. In human anatomy, situs can be solitus (derived from Latin, meaning "normal"), inversus, or ambiguus. Heterotaxy syndrome represents an intermediate arrangement of internal organs between situs solitus and situs inversus, also known as "situs ambiguous." Situs ambiguus describes an abnormal distribution of major visceral organs within the chest and abdomen. The determination of situs as normal, inversus, or ambiguus is primarily based on the location of unpaired organs such as the spleen, liver, stomach, and intestines. Diagnosis is made by clinical examination, echocardiography, a chest X-ray (position of the heart, stomach, and liver), and ultrasound of the abdominal organs. Situs is considered solitus if the left atrium, spleen, stomach, and the trilobed lung are on the left side and the liver and bilobed lung are on the right side. Situs ambiguus is present if the location of unpaired structures is random or indeterminate even after detailed and appropriate imaging. Situs inversus results when the arrangement of the thoracic and abdominal organs is mirrored. Individuals with situs inversus or situs solitus do not experience fatal dysfunction of their organ systems, as general anatomy and morphology of the abdominothoracic organ-vessel systems are conserved.

Investigation of the genetic and clinical features of laterality disorders in prenatal diagnosis: discovery of a novel compound heterozygous mutation in the DNAH11 gene.

BACKGROUND: Left-right laterality disorders are a heterogeneous group of disorders caused by an altered position or orientation of the thoracic and intra-abdominal organs and vasculature across the left-right axis. They mainly include situs inversus and heterotaxy. Those disorders are complicated by cardiovascular abnormalities significantly more frequently than situs solitus. METHODS: In this study, 16 patients with a fetal diagnosis of laterality disorder with congenital heart defects (CHD) were evaluated with a single nucleotide polymorphism array (SNP-arry) combined with whole-exome sequencing (WES). RESULTS: Although the diagnostic rate of copy number variations was 0 and the diagnostic rate of WES was 6.3% (1/16), the likely pathogenic gene DNAH11 and the candidate gene OFD1 were ultimately identified. In addition, novel compound heterozygous mutations in the DNAH11 gene and novel hemizygous variants in the OFD1 gene were found. Among the combined CHD, a single atrium/single ventricle had the highest incidence (50%, 8/16), followed by atrioventricular septal defects (37.5%, 6/16). Notably, two rare cases of common pulmonary vein atresia (CPVA) were also found on autopsy. CONCLUSION: This study identified the types of CHD with a high incidence in patients with laterality disorders. It is clear that WES is an effective tool for diagnosing laterality disorders and can play an important role in future research.

Ultrasound and computed tomography angiography diagnosis of fetal right atrial isomerism with cardiac total anomalous pulmonary venous connection and intestinal malrotation: a case report and literature review.

Right atrial isomerism is a rare and severe isomerism. It is frequently associated with complex congenital heart disease and various extracardiac anomalies. Imaging diagnosis of right atrial isomerism is a challenge. Multisystem and complex anomalies in a 24-week-old fetus were diagnosed with prenatal ultrasound, postnatal computed tomography angiography (CTA), and autopsy. The ultrasound detected most major cardiovascular anomalies including right atrial isomerism and total anomalous pulmonary venous connection. The CTA further detected thoracic and abdominal malformations such as bilateral morphologically right bronchus, diaphragmatic hernia, asplenia, midline liver, and intestinal malrotation. The autopsy confirmed both ultrasound and CTA findings with additional findings, namely, bilateral trilobed lungs and bilateral morphological right auricles. Prenatal ultrasound and postnatal CTA can be complementary to each other in detecting multi-system complex anomalies. Their combined use can be useful for prenatal counseling and postpartum management.

Síndrome de heterotaxia: hallazgos tomográficos / Heterotaxy syndrome: tomographic findings

Resumen El objetivo de este trabajo es caracterizar los aspectos tomográficos relevantes en el síndrome de heterotaxia, mediante cuatro pacientes que ejemplifican los hallazgos más frecuentes en esta patología. Situs solitus es la disposición habitual de los órganos y vasos sanguíneos y situs inversus se refiere a la imagen en espejo del situs solitus. Cuando la disposición de los órganos es indeterminada e impredecible y no se corresponde con el situs solitus ni el situs inversus, estamos frente al situs ambiguus o síndrome de heterotaxia, espectro de anomalías poco frecuente en las relaciones de los órganos toracoabdominales. Puede acompañarse de isomerismo derecho o isomerismo izquierdo. Clasificarlo en dos subgrupos es habitualmente difícil, ya que ninguno de estos tiene hallazgos únicos y patognomónicos, sino que existe amplia superposición. Ambos son de mal pronóstico, en los casos de isomerismo izquierdo un 5-10% llegan a la edad adulta, siendo de peor pronóstico los casos de isomerismo derecho, debido a que presentan inmunodepresión secundaria a la asplenia y cardiopatías congénitas más severas. Se debe analizar cada caso de forma individualizada y detallada para establecer el diagnóstico, determinar la asociación lesional y establecer aquellos pacientes que presenten mayor riesgo de complicaciones.

Abstract The objective of this brief communication is to characterize the relevant tomographic aspects in the heterotaxy syndrome, by means of 4 patients that exemplify the most frequent findings in this pathology. Situs solitus is the usual arrangement of organs and blood vessels and situs inversus refers to the mirror image of situs solitus. When the arrangement of the organs is indeterminate and unpredictable and does not correspond to situs solitus or the situs inversus, we are facing the situs ambiguus or heterotaxy syndrome, abnormal spectrum of anomalies in the relations of the thoracoabdominal organs. It may be accompanied by right isomerism or left isomerism. Attempts to classify it into two subgroups are usually difficult since none of these has unique and pathognomonic findings, but rather there is broad overlap. Both are of poor prognosis, in the cases of left isomerism 5-10% reach adulthood, with a worse prognosis being the cases of right isomerism due to the fact that they have immunodepression secondary to asplenia and more severe congenital cardiopathies. Each case should be analyzed in an individualized and detailed manner to establish the diagnosis, determine the lesional association and establish those patients that present a higher risk of complications.

Diagnóstico por imagen de anomalías en el número y localización del bazo / Diagnostic imaging of abnormalities in the number and location of the spleen

En las exploraciones radiológicas abdominales, algunas anomalías del desarrollo, como el bazo accesorio periesplénico, son fácilmente reconocibles debido a su elevada incidencia. Sin embargo, otras menos frecuentes, como el bazo accesorio intrapancreático, la fusión esplenopancreática o esplenogonadal, la heterotaxia y el bazo errante, así como anomalías adquiridas como la esplenosis, pueden plantear dificultades diagnósticas. El propósito de nuestra revisión es mostrar los hallazgos radiológicos y el diagnóstico diferencial de dichas anomalías esplénicas poco habituales

In imaging studies, some developmental anomalies such as perisplenic accessory spleen are easily recognizable due to their high incidence. However, other, less common anomalies such as intrapancreatic accessory spleen, splenopancreatic fusion, splenogonadal fusion, heterotaxy, and wandering spleen, as well as acquired conditions such as splenosis, can pose diagnostic difficulties. This aim of this review is to show the imaging diagnosis and differential diagnoses of these uncommon splenic anomalies