Congenital and idiopathic scoliosis: clinical and genetic aspects

Using zebrafish as a model system for studying the transgenerational effects of dioxin

2,3,7,8 Tetrachlorodibenzo-p-dioxin (TCDD) has been associated with many disease states in humans. A rising concern is that exposure early in life can lead to adult toxicity and toxicity in subsequent generations. Juvenile zebrafish exposed to TCDD (50 pg/ml in water; 1 h exposure) at 3 and 7 weeks post fertilization showed toxicity only later in adulthood. We have maintained the offspring of these exposed F₀ fish to determine whether we could find adverse affects in the next two generations of F₁ and F₂ offspring. TCDD exposure produced a significantly higher female:male ratio in all three generations. Scoliosis-like axial skeleton abnormalities, not normally observed in controls, were present in the F₁ and F₂ generations descended from the treated F₀ founders. Egg release and fertilization success were reduced in the TCDD lineage F₁ and F₂ generations. This reduction in fertility in the TCDD lineage F₂ generation could be attributed to alterations in the F₂ males. Using zebrafish as a model allowed the simultaneous maintenance of different generations with relatively small space and costs. The zebrafish showed clear signs of transgenerational responses persisting into generations never directly exposed to TCDD.

Neuromonitoring for scoliosis surgery

The use of intraoperative neuromonitoring (IONM) during pediatric scoliosis repair has become commonplace to reduce the risk of potentially devastating postoperative neurologic deficits. IONM techniques include somatosensory evoked potentials, motor evoked potentials, electromyography, and intraoperative wake-up tests. Special considerations for scoliosis repair in pediatric patients include preexisting neurologic deficits and young patients with immature neural pathways in whom neurophysiologic monitoring may prove difficult or unreliable.

Animal models for scoliosis research: state of the art, current concepts and future perspective applications

PURPOSE

The purpose of this study was to provide the readers with a reliable source of animal models currently being utilized to perform state-of-the-art scoliotic research.

MATERIALS AND METHODS

A comprehensive search was undertaken to review all publications on animal models for the study of scoliosis within the database from 1946 to January 2011.

RESULTS

The animal models have been grouped under specific headings reflecting the underlying pathophysiology behind the development of the spinal deformities produced in the animals: genetics, neuroendocrine, neuromuscular, external constraints, internal constraints with or without tissue injury, vertebral growth modulation and iatrogenic congenital malformations, in an attempt to organize and classify these multiple scoliotic animal models. As it stands, there are no animal models that mimic the human spinal anatomy with all its constraints and weaknesses, which puts it at risk of developing scoliosis. What we do have are a multitude of models, which produce spinal deformities that come close to the idiopathic scoliosis deformity.

CONCLUSION

All these different animal models compel us to believe that the clinical phenotype of what we call idiopathic scoliosis may well be caused by a variety of different underlying pathologies.

Some Connectors in Distraction-based Growing Rods Fail More Than Others

STUDY DESIGN

Retrospective review of a prospectively collected patient cohort.

OBJECTIVES

This study examined the rate of failure of various types of spinal rod connectors in distraction-based growing rod constructs for early-onset scoliosis.

SUMMARY OF BACKGROUND DATA

Distraction-based growing rods have a high rate of reported complications.

METHODS

We performed a retrospective review of a single surgeon's consecutive cases with growing rod constructs for early-onset scoliosis. Connector failure was defined as loosening of the connector-rod interface, which resulted in shortening of the construct and loss of distractive force. We included 30 patients with average age of 5 years (range, 1-10 years) with diagnoses of congenital scoliosis (15), neuromuscular (10), idiopathic (4), and other (1). Minimum follow-up was 2 years, with a mean follow-up of 49 months (range, 24-83 months).

RESULTS

Of 98 connectors, there were 12 connector failures (12.2%) in 9 patients. In all failures, the set screw loosened, resulting in rod slippage. On average, failures occurred 25.5 months after the index procedure, and after the third lengthening. Simple side-to-side closed connectors with circular slots had the highest rate of slippage (7 of 17; 41%). Side-to-side connectors with V-groove slots that mechanically lock the rod had 10 times fewer failures, (1 of 27; 4%) (p = .006). Only 1 of 34 longitudinal connectors failed (3%) (p = .002). The average T1-S1 gain during growth was 6.5 mm/year for patients with a connector failure and 9.0 mm/year for those who did not (p = .25). Connectors failed in dual rods (6 of 18; 33%) and single rods (6 of 15; 40%) at similar rates (p = .97).

CONCLUSIONS

Connector failure in distraction-based growing rods is associated with 28% less T1-S1 gain. Side-to-side connectors with circular slots had a failure rate of 41% compared with side-to-side connectors with V-groove slots (4%). Longitudinal connectors had a failure rate of 4%.

Vitamin A deficiency induces congenital spinal deformities in rats

Most cases of congenital spinal deformities were sporadic and without strong evidence of heritability. The etiology of congenital spinal deformities is still elusive and assumed to be multi-factorial. The current study seeks to elucidate the effect of maternal vitamin A deficiency and the production of congenital spinal deformities in the offsping. Thirty two female rats were randomized into two groups: control group, which was fed a normal diet; vitamin A deficient group, which were given vitamin A-deficient diet from at least 2 weeks before mating till delivery. Three random neonatal rats from each group were killed the next day of parturition. Female rats were fed an AIN-93G diet sufficient in vitamin A to feed the rest of neonates for two weeks until euthanasia. Serum levels of vitamin A were assessed in the adult and filial rats. Anteroposterior (AP) spine radiographs were obtained at week 2 after delivery to evaluate the presence of the skeletal abnormalities especially of spinal deformities. Liver and vertebral body expression of retinaldehyde dehydrogenase (RALDHs) and RARs mRNA was assessed by reverse transcription-real time PCR. VAD neonates displayed many skeletal malformations in the cervical, thoracic, the pelvic and sacral and limbs regions. The incidence of congenital scoliosis was 13.79% (8/58) in the filial rats of vitamin A deficiency group and 0% in the control group. Furthermore, vitamin A deficiency negatively regulate the liver and verterbral body mRNA levels of RALDH1, RALDH2, RALDH3, RAR-α, RAR-β and RAR-γ. Vitamin A deficiency in pregnancy may induce congenital spinal deformities in the postnatal rats. The decreases of RALDHs and RARs mRNA expression induced by vitamin A deprivation suggest that vertebral birth defects may be caused by a defect in RA signaling pathway during somitogenesis.

AIS and spondylolisthesis

INTRODUCTION

The association of scoliosis and spondylolisthesis is well documented in literature; the nature and modalities of the relationship of the two pathologies are variable and not always clear. Also, etiologic particulars of scoliosis associated with spondylolisthesis are not well defined, even in cases where scoliosis is called idiopathic. In this paper, we review previous literature and discuss the different aspects of the mutual relationship of scoliosis and spondylolisthesis in the adolescent age.

MATERIALS AND METHODS

It is a common notion that the highest occurrence of scoliosis associated with spondylolisthesis is at the lumbar level, both in adolescent and in adult patients. It is probable that the scoliosis that is more heavily determined by the presence of spondylolisthesis is at the lumbar level and presents curve angle lower than 15° Cobb and mild rotation. The scoliosis with curve value over 15° Cobb that is present at the lumbar level in association with spondylolisthesis probably is not prominently due to spondylolisthesis: in these cases, spondylolisthesis is probably only partially responsible for scoliosis progression with a spasm mechanism and/or due to rotation of slipping "olisthetic" vertebra.

DISCUSSION

We think that the two pathologies should be treated separately, as stated by many other authors, but we would highlight the concept that, whatever be the scoliosis curve origin, spasm, olisthetic or mixed together, this origin has no influence on treatment. The curves should be considered, for all practical effects, as so-called idiopathic scoliosis. We think that generally patient care should be addressed to treat only spondylolisthesis or only scoliosis, if it is necessary on the basis of clinical findings and therapeutic indications of the isolated pathologies, completely separating the two diseases treatments.

CONCLUSIONS

Scoliosis should be considered as an independent disease; only in the case of scoliosis curve progression over time, associated scoliosis must be treated, according to therapeutic principles of the care of any so-called idiopathic scoliosis of similar magnitude, and a similar approach must be applied in the case of spondylolisthesis progression or painful spondylolisthesis.

Ultrasonography-guided percutaneous nephrolithotomy for the treatment of urolithiasis in patients with scoliosis

We examined the surgical outcomes of minimally invasive percutaneous nephrolithotomy (MPCNL) in scoliotic patients with complicating urolithiasis. Two patients with scoliosis were hospitalized for MPNCL due to upper tract urolithiasis. Calyx puncture was performed in the prone position under ultrasonographic guidance. The renal access route was established using a set of 8F to 16F dilators, and a transpyelic ballistic lithotriptor was used to fragment the calculi. The stone burdens in the 2 patients were 410 mm(2) and 500 mm(2). The entire operative time was 40 to 70 minutes, and the mean time of establishing percutaneous access was 20 minutes. The calculi were completely removed by single-session pneumatic lithotripsy. The 2 patients recovered from MPCNL uneventfully, and the follow-up radiologic examinations identified no stone residual or recurrence. MPCNL is a minimally invasive modality that is effective and safe for the treatment of urolithiasis in patients with scoliosis.

Congenital scoliosis: a frontal plane evaluation of 251 operated patients 14 years old or older at follow-up

INTRODUCTION

Congenital scoliosis, carrying an incidence between 0.5 and 1 per 1000 births, raise the problem of their evolutive potential.

HYPOTHESIS

Some predictive factors for the evolution of scoliotic curvature due to congenital vertebral malformation (CVM) can be found.

MATERIAL AND METHODS

This was a retrospective multicenter study of 251 patients, at least 14 years old when evaluated at end of follow-up, with CVM and spinal deformity predominating in the frontal plane.

RESULTS

38.8% of patients showed associated neurologic, visceral or orthopedic abnormalities. CVM was single in 60.6%, double in 20.3%, triple in 6.4% and multiple in 12.7% of cases. 34.1% of CVMs were thoracic. Congenital scoliosis curvature was single in 88.8% of patients, double in 10% and triple in 1.2%. Mean curvature angle was 31.7° at diagnosis (range, 0-105°) and 41.3° preoperatively (range, 10-105°). Sixty-one patients showed associated kyphosis. Mean change in postoperative curvature angle over follow-up was 1.6° (range, -20° to 38°) in the 73 patients managed by arthrodesis, -0.4° (-24° to 30°) in the 64 managed by epiphysiodesis, and 0.4° (-18° to 35°) in the 49 managed by hemivertebral (HV) resection. Results were found to correlate significantly with age at surgery for patients managed by epiphysiodesis, but not for those managed by HV resection or arthrodesis.

DISCUSSION

More than 30% of congenital scolioses involve associated intraspinal abnormality. All CVM patients should therefore undergo medullary and spinal MRI to assess the CVM in all three planes, and the medullary canal and its content. The evolution of scoliotic curvature induced by CVM is hard to predict. Several factors are to be taken into account: CVM type, number and location, and patient age. Curvature progression may be slow or very fast. It accelerates during the peak of puberty, stabilizing with bone maturity. Surgery is mandatory in evolutive scoliosis. Four procedures may be recommended, according to type of CVM and especially to patient age: arthrodesis, convex epiphysiodesis, HV resection or rib distraction. Surgery seeks to correct the spinal deformity induced by the CVM and prevent compensatory curvature and neurologic complications, while conserving sagittal and frontal spinal balance and sparing as many levels as possible. In case of HV involvement, the procedure of choice is CVM resection, which provides 87.5% good results in this indication; the procedure is relatively safe, conservative of spinal levels, and without age limit.

LEVEL OF EVIDENCE

Level IV. Retrospective study.

Mouse phenotyping

Model organisms like the mouse are important tools to learn more about gene function in man. Within the last 20 years many mutant mouse lines have been generated by different methods such as ENU mutagenesis, constitutive and conditional knock-out approaches, knock-down, introduction of human genes, and knock-in techniques, thus creating models which mimic human conditions. Due to pleiotropic effects, one gene may have different functions in different organ systems or time points during development. Therefore mutant mouse lines have to be phenotyped comprehensively in a highly standardized manner to enable the detection of phenotypes which might otherwise remain hidden. The German Mouse Clinic (GMC) has been established at the Helmholtz Zentrum München as a phenotyping platform with open access to the scientific community (www.mousclinic.de; [1]). The GMC is a member of the EUMODIC consortium which created the European standard workflow EMPReSSslim for the systemic phenotyping of mouse models (http://www.eumodic.org/[2]).

The association analysis of TBX6 polymorphism with susceptibility to congenital scoliosis in a Chinese Han population

STUDY DESIGN

A case-control association study was conducted to investigate the genetic etiology for congenital scoliosis (CS) in a Chinese Han population.

OBJECTIVE

To identify whether TBX6 polymorphisms are associated with susceptibility to CS in a Chinese Han population.

SUMMARY OF BACKGROUND DATA

CS is a 3-dimensional deformity of the spine, resulting from defection of normal vertebral development. Although there are many types of defects observed in CS, all result from abnormal formation and segmentation of the vertebral precursors, called somites. Developmental studies in animal models have identified many genes regulating somite formation and segmentation. T-box factor, TBX6, is a prerequisite for somite segmentation in vertebrates. In mouse TBX6 knockouts, the phenotypes are similar with that of some human birth defects, such as CS, raises the possibility that TBX6 gene may be a potential susceptibility gene for CS, so we investigated the relations between TBX6 polymorphisms and CS.

METHODS

Two known single-nucleotide polymorphisms (SNPs) of TBX6 gene were genotyped among 254 Chinese Han subjects (127 CS patients and 127 controls with matched sex and age) by GenomeLab SNPstream genotyping system. The 2 markers (the only tagging SNP and a functional SNP) with minor allele frequency above 5% were analyzed by the allelic and genotypic association analysis, the genotype-phenotype (CS patients were divided into type I 31 cases [failure of formation], type II 46 cases [a failure of segmentation], and type III 50 cases [mixed defects]) association analysis, and the haplotype analysis.

RESULTS

The single SNP analysis showed allele frequency of rs2289292 (exon 8, the only tagging SNP) and rs3809624 (5' untranslated region) demonstrated significant difference between CS cases and controls (P = 0.017 and P = 0.033). No SNP was found to be correlated with clinical phenotype. Moreover, the 2 makers (rs2289292 and rs3809624) in TBX6 gene were found to be in strong linkage disequilibrium (D' = 1.0; gamma = 0.984; 95% confidence interval, 0.96-1.0; LOD = 57.48) in the controls. Both global haplotype analysis and individual haplotype analysis showed that the haplotype of SNP1/SNP2 showed significant association with the disease (P = 0.017), G-A haplotype was more frequently observed in controls than in cases (odds ratio, 0.71; 95% confidence interval, 0.51-0.99).

CONCLUSION

This is the first report on SNPs of TBX6 gene in CS that suggests genetic variants of TBX6 gene is associated with CS and may play an important role in mediating susceptibility to developing CS in the Chinese Han population.

Migraine vestibulopathy in three families with idiopathic scoliosis: a case series

Introduction

We assessed clinical and etiological association between vestibular pathology and idiopathic scoliosis concerning seven members of three families with idiopathic scoliosis.

Case presentation

The families were referred to neurotology center for evaluation of balance problems. Patients were evaluated thorough anamnesis to relevant vestibular and audiological studies in addition to idiopathic scoliosis assessment. All evaluated scoliotic patients had clinical manifestations of vestibular dysfunctions and migrainous headache. All of the scoliotic patients (seven patients) in these three families were diagnosed as migraine vestibulopathy.

Conclusion

With the presentation of these three families, we discussed the probable role of the vestibular dysfunctions including migraine vestibulopathy in the development and progression of idiopathic scoliosis.

The effect of a vertical expandable prosthetic titanium rib on shoulder balance in patients with congenital scoliosis

PURPOSE

To evaluate the effect of a vertical expandable prosthetic titanium rib (VEPTR) on shoulder balance in patients with congenital scoliosis.

METHODS

Fifteen patients had a thoracic congenital scoliosis. The Cobb angles of the thoracic primary curves were measured. Preoperative measurements of the coracoid height difference (CHD; expressed in millimeters) and the clavicular tilt angle difference (CTAD; expressed in degrees) were performed for all patients. All of the patients were treated with VEPTR open wedge thoracostomy.

RESULT

There was a statistically significant improvement in thoracic Cobb angle. At the end of follow-up there was a significant improvement in CHD; all but three of the patients had CHD < 9 mm. Preoperatively, CTAD was 8.9°. It improved to 4.4° postoperatively and significantly decreased to 3.9° by the end of follow-up. Complications included device migration (one patient), infection (one patient), and pedicle screw loosening or displacement (two patients).

CONCLUSION

VEPTR is able to produce a modest intraoperative correction of shoulder imbalance.

SHOX gene is expressed in vertebral body growth plates in idiopathic and congenital scoliosis: implications for the etiology of scoliosis in Turner syndrome

Reduced SHOX gene expression has been demonstrated to be associated with all skeletal abnormalities in Turner syndrome, other than scoliosis (and kyphosis). There is evidence to suggest that Turner syndrome scoliosis is clinically and radiologically similar to idiopathic scoliosis, although the phenotypes are dissimilar. This pilot gene expression study used relative quantitative real-time PCR (qRT-PCR) of the SHOX (short stature on X) gene to determine whether it is expressed in vertebral body growth plates in idiopathic and congenital scoliosis. After vertebral growth plate dissection, tissue was examined histologically and RNA was extracted and its integrity was assessed using a Bio-Spec Mini, NanoDrop ND-1000 spectrophotometer and standard denaturing gel electrophoresis. Following cDNA synthesis, gene-specific optimization in a Corbett RotorGene 6000 real-time cycler was followed by qRT-PCR of vertebral tissue. Histological examination of vertebral samples confirmed that only growth plate was analyzed for gene expression. Cycling and melt curves were resolved in triplicate for all samples. SHOX abundance was demonstrated in congenital and idiopathic scoliosis vertebral body growth plates. SHOX expression was 11-fold greater in idiopathic compared to congenital (n = 3) scoliosis (p = 0.027). This study confirmed that SHOX was expressed in vertebral body growth plates, which implies that its expression may also be associated with the scoliosis (and kyphosis) of Turner syndrome. SHOX expression is reduced in Turner syndrome (short stature). In this study, increased SHOX expression was demonstrated in idiopathic scoliosis (tall stature) and congenital scoliosis.

Genetics of scoliosis

Scoliosis is one of the oldest known deformities of humankind; however, the cause still remains ill defined. Although there is a lack of uniform agreement on the inclusion criteria for the definition of scoliosis, most investigators agree that a coronal curve must measure at least 10 degrees for the patient to be considered to have scoliosis. A broad range of articles were reviewed and the relevant publications that contributed information regarding the genetics of scoliosis were selected for inclusion in this report. Based on family pedigree and genetic studies, the proposed pattern of inheritance for markers of scoliosis are expected to be autosomal dominant, X-linked, multigene, or multifactorial. This is further complicated by locus heterogeneity, allele heterogeneity, and carrier states found in normal individuals. Although none of these modes of inheritance has been definitively proven, it appears that a multifactorial mode of inheritance with variable penetrance is the most likely method.

Progress in the understanding of the genetic etiology of vertebral segmentation disorders in humans

Vertebral malformations contribute substantially to the pathophysiology of kyphosis and scoliosis, common health problems associated with back and neck pain, disability, cosmetic disfigurement, and functional distress. This review explores (1) recent advances in the understanding of the molecular embryology underlying vertebral development and relevance to elucidation of etiologies of several known human vertebral malformation syndromes; (2) outcomes of molecular studies elucidating genetic contributions to congenital and sporadic vertebral malformation; and (3) complex interrelationships between genetic and environmental factors that contribute to the pathogenesis of isolated syndromic and nonsyndromic congenital vertebral malformation. Discussion includes exploration of the importance of establishing improved classification systems for vertebral malformation, future directions in molecular and genetic research approaches to vertebral malformation, and translational value of research efforts to clinical management and genetic counseling of affected individuals and their families.

Systemic first-line phenotyping

With the completion of the mouse genome sequence an essential task for biomedical sciences in the twenty-first century will be the generation and functional analysis of mouse models for every gene in the mammalian genome. More than 30,000 mutations in ES cells will be engineered and thousands of mouse disease models will become available over the coming years by the collaborative effort of the International Mouse Knockout Consortium. In order to realize the full value of the mouse models proper characterization, archiving and dissemination of mouse disease models to the research community have to be performed. Phenotyping centers (mouse clinics) provide the necessary capacity, broad expertise, equipment, and infrastructure to carry out large-scale systemic first-line phenotyping. Using the example of the German Mouse Clinic (GMC) we will introduce the reader to the different aspects of the organization of a mouse clinic and present selected methods used in first-line phenotyping.

Congenital scoliosis in monozygotic twins: case report and review of possible factors contributing to its development

BACKGROUND

The exact etiology of congenital scoliosis remains unknown as yet. It seems that its development may be influenced by both genetic predisposition and environmental factors, at varying degrees. International bibliography features few cases of monozygotic twins with congenital scoliosis. The aim of this study is to report a case in monozygotic twins and review the literature relating to the description of similar cases as well as the pathophysiological mechanism involved in its development.

METHODS

Clinical examination and simple X-rays revealed scoliosis of differing degrees and types in male monozygotic twins with moderate mental retardation and dyslalia.

RESULTS

Congenital scoliosis identified in both twins. In the first, this was manifested as left thoracic scoliosis, with Cobb angle of 34 degrees while in the second as left thoracolumbar scoliosis with Cobb angle of 10 degrees. Both were found to suffer from incarcerated hemivertebrae.

CONCLUSION

According to both its clinical identification and severity and to its course, not only the genetic but the environmental factors seem to play a leading role in the appearance of the condition.

A missense T (Brachyury) mutation contributes to vertebral malformations

No major susceptibility genes for sporadically occurring congenital vertebral malformations (CVM) in humans have been identified to date. Body patterning genes whose mutants cause axial skeletal anomalies in mice are candidates for human CVM susceptibility. T (also known as Brachyury) and TBX6 are critical genes needed to establish mesodermal identity. We hypothesized that mutations in T and/or TBX6 contribute to the pathogenesis of human CVMs. The complete T and TBX6 coding regions, splice junctions, and proximal 500 bp of the promoters were sequenced in 50 phenotyped patients with CVM. Three unrelated patients with sacral agenesis, Klippel-Feil syndrome, and multiple cervical and thoracic vertebral malformations were heterozygous for a c.1013C>T substitution, resulting in a predicted Ala338Val missense alteration in exon 8. A clinically unaffected parent of each patient also harbored the substitution, but the variant did not occur in an ethnically diverse, 443-person reference population. The c.1013C>T variant is significantly associated with CVM (p < 0.001). Alanine 338 shows moderate conservation across species, and valine at this position has not been reported in any species. A fourth patient harbored a c.908-8C>T variant in intron 7. This previously unreported variant was tested in 347 normal control subjects, and 11 heterozygotes and 2 T/T individuals were found. No TBX6 variants were identified. We infer that the c.1013C>T substitution is pathogenic and represents the first report of an association between a missense mutation in the T gene and the occurrence of sporadic CVMs in humans. It is uncertain whether the splice junction variant increases CVM risk. TBX6 mutations do not seem to be associated with CVM. We hypothesize that epistatic interactions between T and other developmental genes and the environment modulate the phenotypic consequences of T variants.

Changes of selenium, copper, and zinc content in hair and serum of patients with idiopathic scoliosis

Our work aimed at extending the search for abnormalities of trace elements in patients with idiopathic scoliosis to the content of zinc (Zn), copper (Cu), and selenium (Se) in these subject's hair and serum. A total of 59 patients (54 girls and 4 boys) with idiopathic scoliosis, aged 13 on the average (range, 10-18 years), were examined. The degree of spine curvature deformity ranged between 12 degrees and 82 degrees . The hair of scoliotic patients under examination showed significantly increased content of zinc 263 +/- 108 microg/g (p < 0.01) and copper 46.2 +/- 37.1 microg/g (p < 0.01), and decreased content of selenium 0.194 +/- 0.114 microg/g (p < 0.01) in comparison with the control group. In scoliotic patients, the Cu/Zn ratio in hair (0.186 +/- 0.139) did not differ significantly from the values found in the probands of the control group (0.115 +/- 0.09). The Cu/Se ratio in this group of patients (254.9 +/- 215.9) was significantly higher (p < 0.001) due to a higher Cu value and a lower Se value in comparison with the controls (47.9 +/- 23.7). In comparison with controls, the serum selenium concentration in the group of scoliotic patients was significantly decreased p < 0.05 (0.74 +/- 0.13 micromol/L and 0.98 +/- 0.12 micromol/L). Various changes in the content of trace elements in biological samples taken from patients with idiopathic scoliosis are not accidental. What might bring about a shift in our knowledge is speciation of various forms of trace elements in the organism in relation to idiopathic scoliosis.

Comparative anti-androgenic actions of vinclozolin and flutamide on transgenerational adult onset disease and spermatogenesis

Exposure of gestating female rats to the anti-androgenic endocrine disruptor vinclozolin has been shown to induce transgenerational adult onset disease phenotypes. The current study, was designed to compare the actions of vinclozolin to the known anti-androgenic compound flutamide. The gestating female rats were exposed to intraperitoneal injections during embryonic day 8-14 (E8-E14) to 100mg/kg/day vinclozolin or flutamide at either 5mg or 20mg/kg/day. As previously observed, vinclozolin induced a transgenerational testis phenotype of increased spermatogenic cell apoptosis and decreased epididymal sperm number. In contrast, the flutamide exposures resulted in a testis phenotype of increased spermatogenic cell apoptosis and decreased epididymal sperm numbers in the F1 generation only, and not the F2 and F3 generation adult males. Interestingly, some of the low dose (5mg/kg) flutamide F2 generation offspring developed spinal agenesis and supernummery development (polymelia) of limbs. Although the actions of vinclozolin and flutamide appear similar in the F1 generation males, the transgenerational effects of vinclozolin do not appear to be acting through the same anti-androgenic mechanism as flutamide.

Musculoskeletal complications of neuromuscular disease in children

A wide variety of neuromuscular diseases affect children, including central nervous system disorders such as cerebral palsy and spinal cord injury; motor neuron disorders such as spinal muscular atrophy; peripheral nerve disorders such as Charcot-Marie-Tooth disease; neuromuscular junction disorders such as congenital myasthenia gravis; and muscle fiber disorders such as Duchenne's muscular dystrophy. Although the origins and clinical syndromes vary significantly, outcomes related to musculoskeletal complications are often shared. The most frequently encountered musculoskeletal complications of neuromuscular disorders in children are scoliosis, bony rotational deformities, and hip dysplasia. Management is often challenging to those who work with children who have neuromuscular disorders.

Lack of evidence of WNT3A as a candidate gene for congenital vertebral malformations

Background

Prior investigations have not identified a major locus for vertebral malformations, providing evidence that there is genetic heterogeneity for this condition. WNT3A has recently been identified as a negative regulator of Notch signaling and somitogenesis. Mice with mutations in Wnt3a develop caudal vertebral malformations. Because congenital vertebral malformations represent a sporadic occurrence, linkage approaches to identify genes associated with human vertebral development are not feasible. We hypothesized that WNT3A mutations might account for a subset of congenital vertebral malformations.

Methods

A pilot study was performed using a cohort of patients with congenital vertebral malformations spanning the entire vertebral column was characterized. DNA sequence analysis of the WNT3A gene in these 50 patients with congenital vertebral malformations was performed.

Results

A female patient of African ancestry with congenital scoliosis and a T12-L1 hemivertebrae was found to be heterozygous for a missense variant resulting in the substitution of alanine by threonine at codon 134 in highly conserved exon 3 of the WNT3A gene. This variant was found at a very low prevalence (0.35%) in a control population of 443 anonymized subjects and 1.1% in an African population.

Conclusion

These data suggest that WNT3A does not contribute towards the development of congenital vertebral malformations. Factors such as phenotypic and genetic heterogeneity may underlie our inability to detect mutations in WNT3A in our patient sample.

Congenital Abnormalities of the Thoracic and Lumbar Spine

Congenital spinal anomalies entail a wide spectrum of conditions that share in common some form of error during embryogenesis. Congenital disorders of the spine may not always be readily apparent at birth; they can present as a deformity with growth or with clinical signs of neurologic dysfunction early or later as an adolescent or adult. In this article the authors briefly summarize the embryology of the spine, which provides a background for understanding the pathophysiology of congenital spinal lesions. The discussion entails spine embryology and the developmental abnormalities commonly seen in the thoracolumbar spine.

Congenital scoliosis: a review and update

Vertebral anomalies causing congenital scoliosis are classified on the basis of failures of formation, segmentation, or both. The natural history depends on the type of anomaly and the location of anomaly. Patient evaluation focuses on the history and physical examination, followed by appropriate imaging modalities. The hallmark of surgical treatment is early intervention before the development of large curvatures. The surgical treatment of a congenital deformity mandates the use of neurological monitoring to minimize the risk of perioperative neurological deficit. Modern surgical techniques have evolved to include the routine use of spinal instrumentation. Patients with associated chest wall deformities or large compensatory curves may be candidates for vertical expansion prosthetic titanium rib placement or growing rods insertion to maximize growth.

DLL3 as a candidate gene for vertebral malformations

Investigations have not identified a major locus for congenital vertebral malformations. Based on observations in mice, we hypothesized that mutations in DLL3, a member of the notch-signaling pathway, might contribute to human vertebral malformations. We sequenced the DLL3 gene in 50 patients with congenital vertebral malformations. A Caucasian male patient with VACTERL manifestations including a T5-T6 block vertebrae was heterozygous for a "G" to "A" missense mutation changing glycine to arginine at codon 269. This residue is conserved in mammals, including chimpanzee, mouse, dog, and rat. Additional testing in the patient did not show evidence of chromosome abnormalities. The patient's asymptomatic mother was also heterozygous for the missense mutation. Since this mutation was not observed in a control population and leads to an amino acid change, it may be clinically significant. The mutation was not found in a control population of 87 anonymous individuals. Several established mechanisms could explain the mutation in both the patient and his asymptomatic mother (susceptibility allele requiring additional environmental factors, somatic mosaicism, multigenic inheritance). Documenting the absence of the mutation in a larger control population or the presence of the mutation in additional affected patients, or documenting a functional difference in DLL3 would provide further evidence supporting its causal role.

[Camptocormia disclosing Parkinson's disease]

Camptocormia is characterised as an extreme bent-forward posture of the trunk that disappears in the recumbent position. On X-ray, trunk flexion appears without vertebral rotation as in scoliosis. The condition is a well-known complication of Parkinson's disease (PD) at the late stage. The authors present the case of a 77-year-old woman affected by severe camptocormia, which appeared and worsened in less than 6 months and hindered gait. Despite no signs of PD, neuro-imaging (DAT-Scan) showed an L-Dopa transducer decrease in putamens. A few weeks later, bradykinesia appeared and the clinical diagnosis of PD became more obvious. L-Dopa improved bradykinesia but did not change the bent-spine posture. A 1-year follow-up showed no other signs of PD other than bradykinesia, but the camptocormia was unchanged.

An analysis of PAX1 in the development of vertebral malformations

An analysis of PAX1 in the development of vertebral malformations. Due to the sporadic occurrence of congenital vertebral malformations, traditional linkage approaches to identify genes associated with human vertebral development are not possible. We therefore identified PAX1 as a candidate gene in vertebral malformations and congenital scoliosis due to its mutation in the undulated mouse. We performed DNA sequence analysis of the PAX1 gene in a series of 48 patients with congenital vertebral malformations, collectively spanning the entire vertebral column length. DNA sequence coding variants were identified in the heterozygous state in exon 4 in two male patients with thoracic vertebral malformations. One patient had T9 hypoplasia, T12 hemivertebrae and absent T10 pedicle, incomplete fusion of T7 posterior elements, ventricular septal defect, and polydactyly. This patient had a CCC (Pro)-->CTC (Leu) change at amino acid 410. This variant was not observed in 180 chromosomes tested in the National Institute of Environmental Health Sciences (NIEHS) single nucleotide polymorphism (SNP) database and occurred at a frequency of 0.3% in a diversity panel of 1066 human samples. The second patient had a T11 wedge vertebra and a missense mutation at amino acid 413 corresponding to CCA (Pro)-->CTA (Leu). This particular variant has been reported to occur in one of 164 chromosomes in the NIEHS SNP database and was found to occur with a similar frequency of 0.8% in a diversity panel of 1066 human samples. Although each patient's mother was clinically asymptomatic and heterozygous for the respective variant allele, the possibility that these sequence variants have clinical significance is not excluded.