Segmental spinal dysgenesis: neuroradiologic findings with clinical and embryologic correlation.
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BACKGROUND AND PURPOSE: Segmental spinal dysgenesis (SSD) is a rare congenital abnormality in which a segment of the spine and spinal cord fails to develop properly. Our goal was to investigate the neuroradiologic features of this condition in order to correlate our findings with the degree of residual spinal cord function, and to provide insight into the embryologic origin of this disorder. We also aimed to clarify the relationship between SSD and other entities, such as multiple vertebral segmentation defects, congenital vertebral displacement, and caudal regression syndrome (CRS). METHODS: The records of patients treated at our institutions for congenital spinal anomalies were reviewed, and 10 cases were found to satisfy the inclusion criteria for SSD. Plain radiographs were available for review in all cases. MR imaging was performed in eight patients, one of whom also underwent conventional myelography. Two other patients underwent only conventional myelography. RESULTS: Segmental vertebral anomalies involved the thoracolumbar, lumbar, or lumbosacral spine. The spinal cord at the level of the abnormality was thinned or even indiscernible, and a bulky, low-lying cord segment was present caudad to the focal abnormality in most cases. Closed spinal dysraphisms were associated in five cases, and partial sacrococcygeal agenesis in three. Renal anomalies were detected in four cases, and dextrocardia in one; all patients had a neurogenic bladder. CONCLUSION: SSD is an autonomous entity with characteristic clinical and neuroradiologic features; however, SSD and CRS probably represent two faces of a single spectrum of segmental malformations of the spine and spinal cord. The neuroradiologic picture depends on the severity of the malformation and on its segmental level along the longitudinal embryonic axis. The severity of the morphologic derangement correlates with residual spinal cord function and with severity of the clinical deficit. (+info)
A role of the cryptic gene in the correct establishment of the left-right axis.
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During vertebrate embryogenesis, a left-right axis is established. The heart, associated vessels and inner organs adopt asymmetric spatial arrangements and morphologies. Secreted growth factors of the TGF-beta family, including nodal, lefty-1 and lefty-2, play crucial roles in establishing left-right asymmetries [1] [2] [3]. In zebrafish, nodal signalling requires the presence of one-eyed pinhead (oep), a member of the EGF-CFC family of membrane-associated proteins [4]. We have generated a mutant allele of cryptic, a mouse EGF-CFC gene [5]. Homozygous cryptic mutants developed to birth, but the majority died during the first week of life because of complex cardiac malformations such as malpositioning of the great arteries, and atrial-ventricular septal defects. Moreover, laterality defects, including right isomerism of the lungs, right or left positioning of the stomach and splenic hypoplasia were observed. Nodal gene expression in the node was initiated in cryptic mutant mice, but neither nodal, lefty-2 nor Pitx2 were expressed in the left lateral plate mesoderm. The laterality defects observed in cryptic(-/-) mice resemble those of mice lacking the type IIB activin receptor or the homeobox-containing factor Pitx2 [6] [7] [8] [9], and are reminiscent of the human asplenic syndrome [10]. Our results provide genetic evidence for a role of cryptic in the signalling cascade that determines left-right asymmetry. (+info)
Neonatal arterial switch operation for transposition of the great arteries in a patient with mirror image dextrocardia and situs inversus totalis.
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The neonatal arterial switch operation has become the standard therapy for D-transposition of the great arteries in the absence of left ventricular outflow tract obstruction. We describe our experience of successful arterial switch operation after balloon atrial septostomy in a 5-day-old infant girl who had atrial and visceral situs inversus totalis, mirror image dextrocardia, and D-transposition of the great arteries. To our knowledge, ours is the first report of this operation in a patient with this anatomy. (+info)
Fetal cardiac dextroposition in the absence of an intrathoracic mass: sign of significant right lung hypoplasia.
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We reviewed our experience of fetal cardiac dextroposition in the absence of an intrathoracic mass. Ten cases were found by fetal echocardiography to have a normal cardiac axis, but the heart was shifted into the right chest and the amount of right lung tissue was reduced. At birth seven of the infants had confirmed structural heart disease (70%), including three with scimitar syndrome. Two infants had additional extracardiac anomalies (20%). Seven infants born at term had clinical pulmonary hypertension with a diagnosis of right lung hypoplasia in all of them. Two neonates died owing to significant heart disease (one with scimitar syndrome and the other with hypoplastic left heart syndrome). Of the three pregnancies that were terminated, the two fetuses with autopsies had severe right lung hypoplasia. Fetal cardiac dextroposition and right pulmonary artery hypoplasia in the absence of an intrathoracic mass are important signs of right lung hypoplasia, which can be associated with significant pathologic cardiac and extracardiac conditions. (+info)
Multiple coronary artery bypass grafting in dextrocardia: case report.
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This is a case report of an unusual case of a patient with dextrocardia and "situs inversus totalis" who presented with unstable angina. Coronary angiography revealed severe main stem and severe triple vessel coronary artery disease. The patient later underwent successful emergency coronary artery bypass graft surgery. To the authors' knowledge this is the first reported case in Malaysia and also, the first ever report in the literature of multiple vessel coronary artery grafting, including the use of the right internal mammary artery. (+info)
Reflections upon the aetiology of congenital pseudarthrosis of the clavicle. With a note on cranio-cleido dysostosis.
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The cause of pseudarthrosis of the clavicle is obscure. Right-sidedness is an almost constant feature. We have proposed that the lesion is sometimes due to pressure upon the developing clavicle by the subclavian artery which is normally at a higher level on the right side. This may be accentuated in the presence of cervical ribs or unduly elevated first ribs, both of which we have observed in association with pseudarthrosis. We have also noted pseudarthrosis on the left side in association with dextrocardia (when the relative positions of the subclavian arteries are reversed) and in the presence of a large left cervical rib. We have speculated upon the nature of the clavicular defect in cranio-cleido dysostosis, in which disorder the first ribs are habitually elevated. A similar mechanism may be involved. (+info)
Cardiopulmonary malformations in the inv/inv mouse.
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The inv/inv mouse carries an insertional mutation in the inversin gene, (inv, for inversion of embryonic turning). Previously it had been reported that almost 100% of the homozygous offspring (inv/inv) were characterized by situs inversus totalis. In this report we identify the spectrum of cardiopulmonary anatomical abnormalities in inv/inv mice surviving to birth to determine whether the abnormalities seen are of the categories classically associated with human situs abnormalities. Stillborn mice, offspring that died unexpectedly (within 48 hr after birth), and neonates with phenotypic characteristics of situs inversus (right-sided stomachs, growth failure or jaundice) were processed for standard histological examination. Of 173 offspring, 34 (20%) neonates (11 stillborn, 9 unexpected deaths, and 14 mice with situs inversus phenotype) were examined, 27 of which were genotyped to be inv/inv. Interestingly, three inv/inv mice (11%) were found to have situs solitus. Twenty-four had situs inversus with normal, mirror-image cardiac anatomy (dextrocardia with atrioventricular concordance, ventriculoarterial concordance and a right aortic arch). The overall incidence of cardiovascular anomalies observed was 10 out of 27 (37%). The most frequent severe malformation, identified in 3 out of 27 animals, was a complex consisting of pulmonary infundibular stenosis/atresia with absence of pulmonary valve tissue and a ventricular septal defect. The pulmonary phenotype in inv/inv mice was situs inversus with occasional minor lobar abnormalities. We conclude that 1) cardiopulmonary malformations in inv/inv mice are not rare (37%), 2) the cardiopulmonary malformations observed in inv/inv specimens are not of the spectrum typically associated with human heterotaxia. In particular, inv/inv mice have a propensity for defects in the development of the right ventricular outflow tract and the interventricular septum, and 3) approximately one out of ten inv/inv mice is born with situs solitus and shows cardiac anomalies that correspond to those observed in inv/inv specimens with situs inversus. Our data therefore suggest that inversin, the product of the inv locus, may have specific roles in cardiac morphogenesis independent of its role in situs determination. (+info)
Liver transplantation from situs inversus to situs inversus.
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Congenital anatomic anomalies often present technical obstacles during liver transplantation. Biliary atresia (BA) is the most common indication for liver transplantation in children, and up to 28% of children with situs inversus are complicated by BA. A boy aged 2 years 11 months with BA, situs inversus, and dextrocardia received a liver transplant from his father. The donor also had situs inversus and dextrocardia without other anomalies. Graft function was excellent postoperatively, and no significant complications were encountered. This is only the second report of the successful use of a living related donor graft for a patient with BA and situs inversus. This case was particularly rare because the donor also had situs inversus, which made the present procedure more feasible. (+info)