Asymmetry: molecular, biologic, embryopathic, and clinical perspectives

Phenotypically Discordant Anomalies in Conjoined Twins: Quirks of Nature Governed by Molecular Pathways?

A multitude of additional anomalies can be observed in virtually all types of symmetrical conjoined twins. These concomitant defects can be divided into different dysmorphological patterns. Some of these patterns reveal their etiological origin through their topographical location. The so-called shared anomalies are traceable to embryological adjustments and directly linked to the conjoined-twinning mechanism itself, inherently located within the boundaries of the coalescence area. In contrast, discordant patterns are anomalies present in only one of the twin members, intrinsically distant from the area of union. These dysmorphological entities are much more difficult to place in a developmental perspective, as it is presumed that conjoined twins share identical intra-uterine environments and intra-embryonic molecular and genetic footprints. However, their existence testifies that certain developmental fields and their respective developmental pathways take different routes in members of conjoined twins. This observation remains a poorly understood phenomenon. This article describes 69 cases of external discordant patterns within different types of otherwise symmetrical mono-umbilical conjoined twins and places them in a developmental perspective and a molecular framework. Gaining insights into the phenotypes and underlying (biochemical) mechanisms could potentially pave the way and generate novel etiological visions in the formation of conjoined twins itself.

Cell chirality exhibition of brain microvascular endothelial cells is dependent on micropattern width

Left-right asymmetry is a conserved property in nature and observed in the human body, a property known as cell chirality. Cell chirality is often studied using micropatterned in vitro models. However, micropattern geometry and size often varies across different studies, making it challenging to compare results. Here, we utilized micropatterned RGD-peptide lines on hyaluronic acid hydrogels to investigate the effect of the micropattern width on the exhibited cell chirality bias of brain microvascular endothelial cells. Overall, this cell type exhibited a negative chirality bias on micropatterned lines ranging from 10 μm to 400 μm in width, where the negative bias was most pronounced on the 100 μm wide lines. We also observed that this exhibited chirality bias varied across the line width. This work serves as a guide to determine optimal micropattern width for further investigations on cell chirality bias and its prominence in e.g., disease states or upon exposure to toxic substances.

Brain endothelial microvascular cell chirality is dependent on micropattern width and spatial localization. Finding the optimal micropattern width and including only the centre cells in the analysis for chirality-based experiments might improve further experimental results.

Asymmetry of Edema Formation: The Possibility of a Somatic Mosaic

A 57-year-old woman experienced an abnormal feeling on the left side of her neck and difficulty breathing 90 minutes after eating Chinese noodles. She had a history of removal of a left sphenoid ridge meningioma one year earlier. She had experienced rigidity of her left neck and peripheral cold sensation on her left side in winter since approximately 10 years of age. She had experienced peripheral swelling of her left side and lower back pain of unknown origin on her left side several times. She had suffered for oral allergy syndrome since she was young. She sometimes experienced a tingling sensation on her lips and an unpleasant feeling in her throat after eating some types of fruit. On arrival, 180 minutes after eating the noodles, she had clear consciousness and stable vital signs. She had left neck and chest swelling without color change. Her difficulty breathing subsided spontaneously. A blood analysis revealed an increased level of immunoglobulin E. Neck computed tomography (CT) with contrast medium and magnetic resonance imaging (MRI) revealed left-side-limited edema in the subcutaneous area and surrounding esophagus and bronchus. These radiological findings denied hemorrhaging or pseudoaneurysmal formation. She underwent observational admission. After her edema improved, she was discharged on the third hospital day. A follow-up examination one week later showed the complete resolution of the neck and chest edema. A blood allergen test did not reveal the cause of the edema. The mechanism underlying the asymmetric transient edema after eating in the present case may involve somatic mosaic.

Comparison of maxillomandibular asymmetries in adult patients presenting different sagittal jaw relationships

OBJECTIVE

The present study aims at using cone beam computed tomography (CBCT) to analyze the maxillomandibular characteristics present in adults with mandibular asymmetries and different sagittal jaw relationships.

METHODS

360 patients were selected and divided into three groups (Class I, Class II, and Class III), with 120 individuals per group. The groups were then subdivided according to the intensity of lateral deviation of the gnathion point, into: 1) relative symmetry, 2) moderate asymmetry, and 3) severe asymmetry. Three planes of reference were established in the CBCT images and several measurements were taken to compare the bilateral skeletal differences between the intensities of asymmetry for the different sagittal jaw relationships.

RESULTS

When the groups were compared by the intensity of asymmetry, significant differences among patients with relative symmetry and moderate to severe asymmetry were found. This was especially noticed for severe asymmetry, suggesting that the deviation of the chin did not constitute the only morphological alteration for these patients, especially because a series of measurements showed significant bilateral differences. When comparing sagittal jaw relationships, the only significant finding was the vertical positioning of the gonion between Class II and III patients with severe asymmetry.

CONCLUSIONS

When comparing the three sagittal jaw relationships with the same intensity of asymmetry, most maxillofacial aspects were quite similar. The only difference was found for patients with severe asymmetry, as the individuals with Class II showed greater bilateral difference in the vertical positioning of the gonion, when compared to patients with Class III.

Mandibular asymmetries and associated factors in orthodontic and orthognathic surgery patients

OBJECTIVES

To estimate the prevalence of mandibular asymmetries in orthodontic and orthognathic surgery patients and to investigate demographic and skeletal factors associated with this disharmony.

MATERIALS AND METHODS

Cone-beam computed tomography images of 1178 individuals aged 19 through 60 years with complete dentitions were analyzed. Outcomes were classified as relative mandibular symmetry, moderate asymmetry, and severe asymmetry. Factors recorded included sex, age, side of mandibular deviation, sagittal jaw relationship, vertical skeletal pattern, angle of the cranial base, and maxillary asymmetry. Ordinal logistic regression was used to estimate simple and adjusted odds ratios (OR) for the individuals with moderate and severe mandibular asymmetry, as well as 95% confidence intervals.

RESULTS

Prevalence values of 55.2%, 27.2%, and 17.6% were observed for relative mandibular symmetry, moderate asymmetry, and severe asymmetry, respectively. An independent association with the side of mandibular deviation and the presence of maxillary asymmetry was observed, both for subjects with moderate mandibular asymmetry (left side: OR = 1.50; 95% CI: 1.01-2.24 / maxillary asymmetry: OR = 2.07; 95% CI: 1.11-3.76) and for those with severe asymmetry (left side: OR = 2.09; 95% CI: 1.27-3.44 / maxillary asymmetry: OR = 4.93; 95% CI: 2.64-9.20).

CONCLUSIONS

Moderate and severe mandibular asymmetries were present in 44.8% of the sample, being associated with the side of mandibular deviation and with maxillary asymmetry.

Craniofacial fibrous dysplasia with facial asymmetry, canted occlusion and open bite: a case report with 2 years follow-up

AIM

Fibrous dysplasia is a benign fibro-osseous disorder of unknown etiology that may affect the craniofacial region causing significant impairment of facial esthetics and function. This paper reports a case of a 21-year-old male, which was investigated and diagnosed with craniofacial fibrous dysplasia involving an overgrowth over right maxillary and mandibular region associated with facial asymmetry, severe occlusal cant and anterior open bite. Management of the case included surgical excision, cosmetic contouring and orthodontic intervention. The case was reviewed over a period of two years, which demonstrate stable treatment outcome.

Higher limb asymmetry in deceased human fetuses and infants with aneuploidy

Aneuploidies cause gene-dosage imbalances that presumably result in a generalized decreased developmental homeostasis, which is expected to be detectable through an increase in fluctuating asymmetry (FA) of bilateral symmetric traits. However, support for the link between aneuploidy and FA is currently limited and no comparisons among different aneuploidies have been made. Here, we study FA in deceased human fetuses and infants from a 20-year hospital collection. Mean FA of limb bones was compared among groups of aneuploidies with different prenatal and postnatal survival chances and two reference groups (normal karyogram or no congenital anomalies). Limb asymmetry was 1.5 times higher for aneuploid cases with generally very short life expectancies (trisomy 13, trisomy 18, monosomy X, triploidy) than for trisomy 21 patients and both reference groups with higher life expectancies. Thus, FA levels are highest in groups for which developmental disturbances have been highest. Our results show a significant relationship between fluctuating asymmetry, human genetic disorders and severity of the associated abnormalities.

Perspectives on asymmetry: the Erickson Lecture

Topics discussed include asymmetry of the brain; prosopagnosia with asymmetric involvement; the blaspheming brain; effects of the numbers of X chromosomes on brain asymmetry; normal facial asymmetry; kissing asymmetry; left- and right-handedness; left-sided baby cradling; Nodal signaling and left/right asymmetry; primary cilium and left/right asymmetry in zebrafish; right/left asymmetry in snails; species differences in Shh and Fgf8; primary cilium in vertebrate asymmetry; Hedgehog signaling on the cilium; Wnt signaling on the cilium; situs solitus, situs inversus, and situs ambiguus (heterotaxy); ciliopathies; right-sided injuries in trilobites; unilateral ocular use in the octopus; fiddler crabs; scale-eating cichlids; narwhals; left-footed parrots; asymmetric whisker use in rats; and right-sided fatigue fractures in greyhounds.

A Child With an FGFR3 Mutation, a Laterality Disorder and an Hepatoblastoma: Novel Associations and Possible Gene–Environment Interactions

We report on a 3-year-old girl, from a 3-generation family with an FGFR3 Pro250Arg mutation, who in addition to craniosynostosis, had a laterality disorder and hepatoblastoma, following a pregnancy complicated by maternal insulin-dependent diabetes. The clinical features possibly result from the combined effects of the maternal diabetes and the familial FGFR3 mutation, thus representing a unique gene–environment interaction that may have implications for the understanding of the phenotypes described in this child.

Intracranial aneurysms in klippel-trenaunay/weber syndromes: case report

OBJECTIVE

We present a comprehensive review of intracranial aneurysms in Klippel-Trenaunay and Klippel-Trenaunay-Weber syndromes (KTS/KTWS), and examine factors influencing the risks of surgery vs conservative management.

CLINICAL PRESENTATION

A 58-year-old physician with KTS affecting the right extremities presented with left hemispheric cerebellar stroke and was discovered to harbor four intracranial aneurysms of the posterior circulation: fusiform mid and distal BA (2.6 x 2 x 2 cm), fusiform right proximal P1 (2 x 1.3 x 1.3 cm), fusiform right distal P1 (2.8 x 2.7 x 2 cm), and saccular left distal posterior inferior cerebellar artery (2.5 x 2.5 x 2.5 cm). Ten years later he had an infarct in the paramedian distribution of the basilar artery and a right internal capsule stroke. Two months later, he developed hydrocephalus, ultimately presenting in status epilepticus 4 months later secondary to ongoing aneurysm expansion and mass effect.

INTERVENTION

Systemic anticoagulation for acute thrombosis with possible distal arterioarterial embolization from giant P1 aneurysms. Ventriculoperitoneal shunting for hydrocephalus. The patient died within 9 days after admission and 10 years after the initial discovery of aneurysms.

CONCLUSION

Strict control of modifiable risk factors compromising vascular integrity and periodic neuroimaging are warranted in KTS/KTWS patients. KTS/KTWS patients are hypercoagulable, and may be predisposed to aneurysm thrombosis with increased risk for distal arterial microembolization. Stroke-related morbidity secondary to distal arterioarterial aneurysm thrombus embolization and acute aneurysm thrombosis may be decreased with systemic anticoagulation in this patient population. KTS/KTWS patients have significantly higher rates of DVT and PE than the general population, and should be classified in the high-risk category for venous thromboembolism prophylaxis. Both endovascular and open cerebrovascular techniques have been used successfully in KTS/KTWS patients with intracranial aneurysms.

Combined congenital radial and ulnar longitudinal deficiencies: report of 2 cases

Variation in longitudinal deficiencies is likely related to the timing and duration of an insult during early limb development. In experimental models, teratogenic insults induce ulnar deficiencies earlier in gestation than radial deficiencies. In this report, we describe the rare combination of right radial and left ulnar deficiencies in 2 cases. Interestingly, 1 case had a history of 2 separate and apparently distinct episodes of bleeding during early gestation, whereas the other demonstrated associated hematoma formation early in development. These cases also demonstrate the susceptibility for ulnar defects on the left and radial defects on the right. The authors discuss the relationship of prenatal insults on limb development and the mechanisms underlying longitudinal deficiencies.

Increased prevalence of left-handedness in hemifacial microsomia

Ten percent of people are left handed, but a higher frequency has been associated with certain craniofacial malformations, such as cleft lip and unilateral coronal synostosis. The purpose of this study was to determine the frequency of left-handedness in patients with hemifacial microsomia (HFM). Patients with HFM were identified in our craniofacial database. Normal controls were recruited by local pediatricians. Data gathered included age, sex, and handedness (determined by writing and/or drawing); the orbit, mandible, ear, nerve, and soft tissue (OMENS)-plus score and side of involvement were tabulated for patients with HFM. Hand preference was compared between the groups using chi analysis; possible correlations were analyzed between handedness and age, sex, the OMENS score, extracraniofacial findings, and side of involvement. One hundred seventy-eight patients with HFM were identified; 92 (51%) were excluded. Of the 86 included, 48% were boys (n = 47) and the mean age at inquiry was 13.5 years. Predominant side of involvement was right in 49% (n = 42) and left in 38% (n = 33). Eleven patients (13%) had severe involvement of both sides. Expanded-spectrum HFM was documented in 41% of patients. Ninety-six children were in the control group; 44% were boys (n = 42), and the mean age was 10 years. The difference in age between the groups was significant (P < 0.05), but sex differences were not. Patients with HFM were more likely to be left handed for writing compared with the control group (26% vs. 11%; P < 0.05). The frequency was higher, 36%, in those with bilateral involvement (P > 0.05). There was no correlation with predominant side or OMENS score. This study confirms that this disorder affects cerebral lateralization.

What's left in asymmetry?

Left-right patterning is a fascinating problem of morphogenesis, linking evolutionary and cellular signaling mechanisms across many levels of organization. In the past 15 years, enormous progress has been made in elucidating the molecular details of this process in embryos of several model species. While many outside the field seem to believe that the fundamental aspects of this pathway are now solved, workers on asymmetry are faced with considerable uncertainties over the details of specific mechanisms, a lack of conceptual unity of mechanisms across phyla, and important questions that are not being pursued in any of the popular model systems. Here, we suggest that data from clinical syndromes, cryptic asymmetries, and bilateral gynandromorphs, while not figuring prominently in the mainstream work on LR asymmetry, point to crucial and fundamental gaps of knowledge about asymmetry. We identify 12 big questions that provide exciting opportunities for fundamental new advances in this field.

Smad3 and Pitx2 cooperate in stimulation of FSHbeta gene transcription

Activin is a member of the TGFbeta superfamily of growth and differentiation factors that control a variety of cellular and physiological functions. The canonical intracellular pathway of this ligand is well established and involves Smad signaling molecules. The tissue- and cell-specificity of activin action is achieved by Smad interaction with various transcriptional co-factors in the nucleus. In the reproductive axis, activin induces biosynthesis and secretion of follicle stimulating hormone (FSH) through transcriptional control of FSHbeta-subunit. Whereas it has been well demonstrated that this regulation is mediated by Smad pathway, the molecular mechanisms underlying gonadotrope-specific expression of the FSHbeta gene are not fully understood. Previously, we have identified Pitx2 as a pituitary-expressed transcription factor involved in activin-dependent induction of the FSHbeta promoter. Present data demonstrate that Pitx2 is not only sufficient, but also necessary for FSHbeta gene transcription, as a siRNA-mediated downregulation of Pitx2 protein expression abrogates both Smad3- and activin-mediated stimulation of the FSHbeta promoter. In addition, downregulation of Smad3 protein expression has a significant effect on Pitx2-dependent stimulation of the FSHbeta promoter, suggesting that cooperation between these factors is necessary for full transcriptional activation of the FSHbeta promoter. Furthermore, we show that Pitx2/Smad protein complexes assemble and can be co-immunoprecipitated. This interaction is mediated through the homeodomain of Pitx2 and is important for stimulation of FSHbeta gene transcription. Overall, these data contribute to the emerging molecular mechanism underlying both basal and activin-dependent FSHbeta gene regulation.

Different gene expressions on the left and the right: a genotype/phenotype mismatch in need of attention

Discordance in monozygotic twins has traditionally been explained in terms of environmental influences. A recent investigation has found a difference in epigenetic markers in older but not in younger twins. However, phenotypic differences that depend on an individual's postnatal life style do not address the problem of discordance in congenital malformations, or the reason why malformations are frequently unilateral, often with a preference for one or the other side. One such condition, cleft lip with or without cleft palate, which is preferentially expressed on the left, is a multifactorial condition, that is caused by a failure of the critical timing necessary for different groups of cells to meet and develop into a normal face. This process is dependent on cell proliferation and migration, which are energy-dependent, while the additional requirement for apoptosis to allow cell fusion suggests the involvement of mitochondria. Recent progress in two separate areas of research could lead to a better understanding of the problem of facial clefts: (1) the recognition of an interaction between gene products and mitochondria in the aetiology of neurodegenerative diseases and (2) the discovery of an increasing number of genes, including transcription factors, growth factors and members of the TGF-beta signalling family, that are differentially expressed on the left and right side, thus pointing to a difference in their micro-environment. These findings emphasize the importance of investigating the activity of candidate genes for complex developmental processes separately on the left and right sides. Data presented in this review suggest that differential growth rates may lead to an inversion of laterality. A method is described to test for a possible mitochondrial difference between left and right sides, using a mouse model with cleft lip.

Left-right patterning from the inside out: widespread evidence for intracellular control

The field of left-right (LR) patterning--the study of molecular mechanisms that yield directed morphological asymmetries in otherwise symmetrical organisms--is in disarray. On one hand is the undeniably elegant hypothesis that rotary beating of inclined cilia is the primary symmetry-breaking step: they create an asymmetric extracellular flow across the embryonic midline. On the other hand lurk many early symmetry-breaking steps that, even in some vertebrates, precede the onset of ciliary flow. We highlight an intracellular model of LR patterning where gene expression is initiated by physiological asymmetries that arise from subcellular asymmetries (e.g. motor-protein function along oriented cytoskeletal tracks). A survey of symmetry breaking in eukaryotes ranging from protists to vertebrates suggests that intracellular cytoskeletal elements are ancient and primary LR cues. Evolutionarily, quirky effectors like ciliary motion were likely added later in vertebrates. In some species (like mice), developmentally earlier cues may have been abandoned entirely. Late-developing asymmetries pose a challenge to the intracellular model, but early mid-plane determination in many groups increases its plausibility. Multiple experimental tests are possible.

Is the early left-right axis like a plant, a kidney, or a neuron? The integration of physiological signals in embryonic asymmetry

Embryonic morphogenesis occurs along three orthogonal axes. While the patterning of the anterior-posterior and dorsal-ventral axes has been increasingly well-characterized, the left-right (LR) axis has only relatively recently begun to be understood at the molecular level. The mechanisms that ensure invariant LR asymmetry of the heart, viscera, and brain involve fundamental aspects of cell biology, biophysics, and evolutionary biology, and are important not only for basic science but also for the biomedicine of a wide range of birth defects and human genetic syndromes. The LR axis links biomolecular chirality to embryonic development and ultimately to behavior and cognition, revealing feedback loops and conserved functional modules occurring as widely as plants and mammals. This review focuses on the unique and fascinating physiological aspects of LR patterning in a number of vertebrate and invertebrate species, discusses several profound mechanistic analogies between biological regulation in diverse systems (specifically proposing a nonciliary parallel between kidney cells and the LR axis based on subcellular regulation of ion transporter targeting), highlights the possible importance of early, highly-conserved intracellular events that are magnified to embryo-wide scales, and lays out the most important open questions about the function, evolutionary origin, and conservation of mechanisms underlying embryonic asymmetry.

A female with hemihypertrophy and chylous ascites – Klippel–Trenaunay syndrome or Proteus syndrome: a diagnostic dilemma

Asymmetric overgrowth has many differential diagnoses with considerable overlap, posing a diagnostic dilemma. The presence of chylous ascites, though unreported, might be expected as a manifestation of overgrowth syndromes with lymphatic involvement. We present a patient with hemihypertrophy who presented with chylous ascites at birth.

Syndromes and constitutional chromosomal abnormalities associated with Wilms tumour

Wilms tumour has been reported in association with over 50 different clinical conditions and several abnormal constitutional karyotypes. Conclusive evidence of an increased risk of Wilms tumour exists for only a minority of these conditions, including WT1 associated syndromes, familial Wilms tumour, and certain overgrowth conditions such as Beckwith-Wiedemann syndrome. In many reported conditions the rare co-occurrence of Wilms tumour is probably due to chance. However, for several conditions the available evidence cannot either confirm or exclude an increased risk, usually because of the rarity of the syndrome. In addition, emerging evidence suggests that an increased risk of Wilms tumour occurs only in a subset of individuals for some syndromes. The complex clinical and molecular heterogeneity of disorders associated with Wilms tumour, together with the apparent absence of functional links between most of the known predisposition genes, suggests that abrogation of a variety of pathways can promote Wilms tumorigenesis.

Constitutional UPD for chromosome 11p15 in individuals with isolated hemihyperplasia is associated with high tumor risk and occurs following assisted reproductive technologies

Isolated hemihyperplasia (IH) refers to a distinct diagnosis involving asymmetric overgrowth of single or multiple organs or regions of the body and can result from various genomic changes including molecular alterations of 11p15; these are paternal uniparental disomy (UPD), and alterations of methylation at two imprinting centers at 11p15: IC1 (H19) and IC2 (KCNQ1OT1). As little information is available on the molecular basis of tumor development in IH, or on the frequency of tumors in children with different molecular subtypes of IH, molecular testing was undertaken on 51 patients with IH and revealed: 8 (16%) with UPD, 3 (6%) with hypomethylation at KCNQ1OT1, and 0 with hypermethylation at H19. Of the 8 patients with UPD, 4 had tumors (3 hepatoblastomas, 1 Wilms tumor); 0/3 patients with hypomethylation at KCNQ1OT1 had a tumor; of the remaining 40 with no molecular alterations, 6 had tumors (3 Wilms tumors, 2 neuroblastomas, 1 adrenocortical adenoma). The 50% tumor frequency in patients with IH and UPD was statistically significantly higher than the 15% tumor frequency in those with IH and no molecular alteration detected (Fisher's exact test P = 0.047, OR 5.67). This is the first demonstration that UPD at 11p15 in patients with IH confers a higher tumor risk than in patients with IH without this molecular change. Of note, two of the eight patients with UPD and IH were conceived using assisted reproductive technologies (ART), thus raising the question whether ART might impact the rate of somatic recombination during embryonic development.

Atypical presentations of spinal muscular atrophy type III (Kugelberg-Welander disease)

Spinal muscular atrophy type III (SMA III, Kugelberg-Welander disease) typically presents with symmetric proximal weakness, areflexia, and hypotonia. We present four children with spinal muscular atrophy type III who had atypical phenotypes. Three patients clearly had asymmetric weakness at presentation and two had upper motor neuron signs in the lower extremities (one patient had both features). Two of the patients had prolonged evaluations before the diagnosis was made. All patients had Gowers signs and two had pes planus. In patients with proximal muscle weakness the presence of asymmetrical weakness, upper motor neuron signs, or both, may be compatible with spinal muscular atrophy type III. The diagnosis of spinal muscular atrophy should be considered when other possibilities have been excluded.

Apert syndrome with glucose-6-phosphate dehydrogenase deficiency: a case report

Apert syndrome is characterized by midface hypoplasia, syndactyly of the hands and feet, proptosis of eyes, steep and flat frontal bones, and premature union of cranial sutures. Maxillary hypoplasia, deep palatal vault, anterior open bite, crowding of the dental arch, severely delayed tooth eruption, and dental malocclusion are the main oral manifestations of this syndrome. In this report, a case of Apert syndrome with glucose-6-phosphate dehydrogenase (G(6)PD) deficiency is presented. The patient, a 4-year-old male and the fourth child of healthy parents, was admitted to our department because of delayed tooth eruption. He had all the cardinal symptoms of the Apert syndrome. Clinical examination revealed that primary centrals, canines and first molars erupted; however, primary second molars and laterals had not erupted. The patient had no dental caries. Preventive treatments were applied, and subsequently, the patient was taken to long-term follow up.

Difficulties in differentiation of Parry-Romberg syndrome, unilateral facial sclerodermia, and Rasmussen syndrome

INTRODUCTION

Parry-Romberg syndrome (progressive facial hemiatrophy) is a unilateral, slowly progressive atrophy affecting the skin, subcutaneous tissues, muscles, and bones. The relationship between Parry-Romberg syndrome and connective tissue disorders, especially scleroderma en coup de sabre, is still unclear. The neurological symptoms, including epilepsy, migraine, and brain lesion, on neuroimaging may be similar. Rasmussen encephalitis (RE) is connected with chronic inflammation and damage of one hemisphere. Clinically, it is manifested by epileptic partial seizures and unilateral neurological symptoms.

CASE REPORT

The authors present the case of a 10-year-old girl with features suggestive of RE, with refractory partial motor dextrolateral seizures followed by development of hemiparesis and with progressive intellectual deterioration. At the age of 2 years, some changes on the left part of the face typical of Parry-Romberg syndrome or a linear form of scleroderma were noticed.

DISCUSSION

The authors discussed the difficulties in differential diagnosis in that patient. The presented girl constitute the case from the borderline zone of the aforementioned disorders.

Alterations in heart looping induced by overexpression of the tight junction protein Claudin-1 are dependent on its C-terminal cytoplasmic tail

In vertebrates, the positioning of the internal organs relative to the midline is asymmetric and evolutionarily conserved. A number of molecules have been shown to play critical roles in left-right patterning. Using representational difference analysis to identify genes that are differentially expressed on the left and right sides of the chick embryo, we cloned chick Claudin-1, an integral component of epithelial tight junctions. Here, we demonstrate that retroviral overexpression of Claudin-1, but not Claudin-3, on the right side of the chick embryo between HH stages 4 and 7 randomizes the direction of heart looping. This effect was not observed when Claudin-1 was overexpressed on the left side of the embryo. A small, but reproducible, induction of Nodal expression in the perinodal region on the right side of the embryo was noted in embryos that were injected with Claudin-1 retroviral particles on their right sides. However, no changes in Lefty,Pitx2 or cSnR expression were observed. In addition, Flectin expression remained higher in the left dorsal mesocardial folds of embryos with leftwardly looped hearts resulting from Claudin-1 overexpression on the right side of the embryo. We demonstrated that Claudin-1's C-terminal cytoplasmic tail is essential for this effect: mutation of a PKC phosphorylation site in the Claudin-1 C-terminal cytoplasmic domain at threonine-206 eliminates Claudin-1's ability to randomize the direction of heart looping. Taken together, our data provide evidence that appropriate expression of the tight junction protein Claudin-1 is required for normal heart looping and suggest that phosphorylation of its cytoplasmic tail is responsible for mediating this function.

Genetics of polarity in mammalian embryos

This brief review is devoted to the genetic control of polarity and embryonic axes in preimplantation mammalian embryos. Discussion is related to their formation, the considerable variations in gene activity in these early phases of development, and the influence of timers over polarities and related aspects of development. Modern genetic analyses assess vast numbers of genes in outline, and the actions of individual genes in detail. These factors operate within a mixture of inherited maternal controls, gene silencing, bouts of transcription and the actions of mini RNA in controlling gene expression. Within this context, maternal factors regulate the planes of early cleavage divisions and unevenly distribute animal and vegetal characteristics to successive blastomeres by the 4-cell stage. This varied inheritance confers varying combinations of animal and vegetal cytoplasm to single blastomeres in many human 4-cell embryos. The blastomere inheriting animal cytoplasm only may be the trophectodermal stem cell, that with vegetal cytoplasm may be the germline precursor, and the two with full polarity may produce inner cell mass. Some implications of these findings are considered.

Primary ciliary dyskinesia: a review

The entity sinusitis, bronchiectasis, and situs inversus is since long named Kartagener syndrome. Nowadays the designation used is primary ciliary dyskinesia (PCD), which implies cilia with decreased or total absence of motility, which may result in sinusitis, chronic bronchitis, bronchiectasis, and male infertility. A large number of deficiencies detectable on the ultrastructural level give rise to PCD. There may also be aberrations not detected up to the present. The normal left-right asymmetry of the body is thought to be due to the beating of the cilia in the embryonic (Hensen's) node. Total immotility of the cilia should therefore result in random asymmetry of the body that is situs inversus in 50% of the cases. It has also been claimed that 50% of cases with PCD have situs inversus. However, several deficiencies apparently do not cause total immotility, and all ultrastructural variants are not associated with situs inversus in 50% of the cases. Several of the deficiencies are difficult to detect. Optimal fixation and handling are therefore obligatory. The genetic changes behind the variants are now being studied in several laboratories. Patients with PCD have very low levels of nasal nitric oxide, which is of increasing diagnostic importance. Other established diagnostic methods are the saccharine test and determination of ciliary beat frequency.

MR imaging of fetal head and neck anomalies

This article describes an approach to imaging of fetal head and neck anomalies. Topics include cleft lip and palate, facial clefts, amniotic band sequence, micrognathia and retrognathia, ocular and orbital abnormalities, craniosynostosis, posterior nuchal translucency, cephaloceles, vascular anomalies, and tumors. Some of the more common syndromes are also described.

Sphingosine 1-phosphate receptor regulation of N-cadherin mediates vascular stabilization

Vascular stabilization, a process by which nascent vessels are invested with mural cells, is important in angiogenesis. Here we describe the molecular basis of vascular stabilization regulated by sphingosine 1-phosphate (S1P), a platelet-derived lipid mediator. S1P1 receptor-dependent cell-surface trafficking and activation of the cell-cell adhesion molecule N-cadherin is essential for interactions between endothelial and mural cells. Endothelial cell S1P1/Gi/Rac pathway induces microtubule polymerization, resulting in trafficking of N-cadherin to polarized plasma membrane domains. S1P treatment modulated the phosphorylation of N-cadherin as well as p120-catenin and induced the formation of cadherin/catenin/actin complexes containing novel regulatory and trafficking factors. The net result of endothelial cell S1P1 receptor activation is the proper trafficking and strengthening of N-cadherin-dependent cell-cell adhesion with mural cells. Perturbation of N-cadherin expression with small interfering RNA profoundly attenuated vascular stabilization in vitro and in vivo. S1P-induced trafficking and activation of N-cadherin provides a novel mechanism for the stabilization of nascent blood vessels by mural cells and may be exploited to control angiogenesis and vascular diseases.

Non-syndromic hemihyperplasia in a male and his mother

We present two family members with non-syndromic hemihyperplasia (HHP), which developed in adolescence. We have reviewed reported familial cases of HHP and conclude that presentation is similar to sporadi cases and that all affected family members have been related through a maternal relative.

Molecular insights into congenital disorders of the digestive system

Recent work is providing new insights into molecular mechanisms of digestive system development and their alteration in clinically significant disorders. An understanding of these mechanisms has largely been gained through the use of animal models, because many of the basic processes required in embryogenesis are functionally conserved among species. Such conserved factors include cell-cell signaling pathways and the regulation of gene expression. Disruption of these pathways have been implicated in several congenital disorders of the digestive system, including Hirschsprung disease, malrotation, altered sphincter development, Meckel diverticulum, biliary atresia, Alagille syndrome, pancreatic heterotopias, and pancreatic agenesis. In this review, we highlight recent studies in digestive system development, which elucidate mechanisms underlying congenital disorders of the human digestive system.

Presence of vascular anomalies with congenital hemihypertrophy and Wilms tumor: an evidence-based evaluation

Congenital hemihypertrophy is an uncommon condition of unknown etiology characterized by unilateral overgrowth of part or all of one side of the body. Hemihypertrophy is known to be associated with certain childhood tumors, most notably Wilms tumor (or nephroblastoma), and for this reason infants with hemihypertrophy are often followed with serial abdominal ultrasounds. Klippel-Trénaunay syndrome (KTS) is the triad of port-wine stain, venous varicosities, and soft tissue and/or bony hypertrophy. Children with KTS typically have localized rather than generalized hemihypertrophy, but occasionally the hypertrophy is more extensive than the vascular anomaly itself. Information is lacking about whether hemihypertrophy in this setting can also be a risk factor for Wilms tumor. We systematically reviewed the medical literature to determine whether well-documented cases of Wilms tumor in the setting of both hemihypertrophy and vascular anomalies have been described, and if found, whether the association was sufficiently frequent that routine screening for Wilms tumor in this setting should be recommended. A review of case reports and case series in the pediatric population was undertaken using specific inclusion and exclusion criteria. We found 4 of 58 subjects with hemihypertrophy and Wilms tumor had a reported vascular anomaly, but in only one case was a clear-cut diagnosis of KTS confirmed. The relationship of the other three vascular anomalies reported was of uncertain significance. In conclusion, our review suggests that the risk of Wilms tumor in the setting of localized soft-tissue hypertrophy in conjunction with a vascular malformation is quite low. More extensive hemihypertrophy extending to body sites remote from the vascular malformation itself could have a higher risk of Wilms tumor, although the magnitude of this risk is uncertain. Our findings suggest that routine serial abdominal ultrasounds in patients with vascular malformations in association with localized soft-tissue hypertrophy are unwarranted.

Aspects of the molecular regulation of early mammalian development

Many regulatory systems operate in the early mammalian embryo. This brief overview surveys several systems and their integration including polarities and axes, left-right differentiation, timers in cells, tissues and in gene expression, and imprinting. Polarities are essential from the very earliest stages of oocyte formation, and maintain their significance until blastocyst stages and beyond. They determine cleavage axes and the distribution of maternal proteins in the oocyte, distinct distributions being identified at the animal pole especially. Left-right axes are no doubt expressed from the earliest embryonic stages, and perhaps even in determining slight differences in the axes of cleavage and of maternal protein distribution. Timers, equally fundamental, have been demonstrated to control many functions in oocytes and embryos. Many fundamental processes in early mammalian oocytes and embryos are closely timed. They are classified into circadian rhythms, hourglass timers, clocks regulating major aspects of development including transcription, longevity via telomere clocks and long-range systems. Imprinting and methylation, increasingly important in establishing stable phenotypes in early embryos, might develop abnormally under some circumstances including intracytoplasmic sperm injection and cloning. A general summary briefly describes some other aspects of regulation, especially chromosomal anomalies in human embryos.