Idiopathic scoliosis in twins studied by DNA fingerprinting: the incidence and type of scoliosis

Rare variant association analyses reveal the significant contribution of carbohydrate metabolic disturbance in severe adolescent idiopathic scoliosis

BACKGROUND

Adolescent idiopathic scoliosis (AIS), the predominant genetic-influenced scoliosis, results in spinal deformities without vertebral malformations. However, the molecular aetiology of AIS remains unclear.

METHODS

Using genome/exome sequencing, we studied 368 patients with severe AIS (Cobb angle >40°) and 3794 controls from a Han Chinese cohort. We performed gene-based and pathway-based weighted rare variant association tests to assess the mutational burden of genes and established biological pathways. Differential expression analysis of muscle tissues from 14 patients with AIS and 15 controls was served for validation.

RESULTS

SLC16A8, a lactate transporter linked to retinal glucose metabolism, was identified as a novel severe AIS-associated gene (p=3.08E-06, false discovery rate=0.009). Most AIS cases with deleterious SLC16A8 variants demonstrated early onset high myopia preceding scoliosis. Pathway-based burden test also revealed a significant enrichment in multiple carbohydrate metabolism pathways, especially galactose metabolism. Patients with deleterious variants in these genes demonstrated a significantly larger spinal curve. Genes related to catabolic processes and nutrient response showed divergent expression between AIS cases and controls, reinforcing our genomic findings.

CONCLUSION

This study uncovers the pivotal role of genetic variants in carbohydrate metabolism in the development of AIS, unveiling new insights into its aetiology and potential treatment.

Association between genetic polymorphisms and risk of adolescent idiopathic scoliosis in case-control studies: a systematic review

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a structural lateral spinal curvature of ≥10° with rotation. Approximately 2%-3% of children across populations are affected with AIS, and this condition is responsible for ~$3 billion in costs within the USA. Although AIS is believed to have a strong genetic contribution, clinical translation of identified genetic variants has stalled.

METHODS

The databases MEDLINE (via PubMed), Embase, Google Scholar and Ovid MEDLINE were searched and limited to articles in English. Title and abstract, full-text and data extraction screening was conducted through Covidence, followed by data transfer to a custom REDCap database. Studies containing variant-level data using genome-wide methodology as well as validation studies of genome-wide methods were considered. Quality assessment was conducted using Q-Genie.

RESULTS

33 studies were included, including 9 genome-wide association studies, 4 whole exome sequencing and 20 validation studies. Combined, these studies included data from >35,000 cases and >67,000 controls, not including validation cohorts. Additionally, results from six meta-analyses containing novel cohorts were also reported. All included study cohorts were from populations of primarily East Asian or Caucasian descent. Quality assessment found that overall study quality was high and control group selection was moderate. The highest number of reported associations were in single nucleotide polymorphisms (SNPs) in or near LBX1, LBX1-AS1, GPR126/ADGRG6 or BNC2.

CONCLUSION

AIS risk may be influenced by specific SNPs, particularly those in/near LBX1 and GPR126. Translatability of study findings is unknown due to an underrepresentation of most ethnic groups as well as few identified genome-wide studies. Further studies may benefit from increased cohort diversity and thorough evaluation of control cohort groups.

Genetic variants associated with the occurrence and progression of adolescent idiopathic scoliosis: a systematic review protocol

BACKGROUND

Adolescent idiopathic scoliosis (AIS) is a structural lateral spinal curvature of ≥ 10° with rotation. Approximately 2-3% of children in most populations are affected with AIS, and this condition is responsible for approximately $1.1 billion in surgical costs to the US healthcare system. Although a genetic factor for AIS has been demonstrated for decades, with multiple potentially contributory loci identified across populations, treatment options have remained limited to bracing and surgery.

METHODS

The databases MEDLINE (via PubMed), Embase, Google Scholar, and Ovid MEDLINE will be searched and limited to articles in English. We will conduct title and abstract, full-text, and data extraction screening through Covidence, followed by data transfer to a custom REDCap database. Quality assessment will be confirmed by multiple reviewers. Studies containing variant-level data (i.e., GWAS, exome sequencing) for AIS subjects and controls will be considered. Outcomes of interest will include presence/absence of AIS, scoliosis curve severity, scoliosis curve progression, and presence/absence of nucleotide-level variants. Analyses will include odds ratios and relative risk assessments, and subgroup analysis (i.e., males vs. females, age groups) may be applied. Quality assessment tools will include GRADE and Q-Genie for genetic studies.

DISCUSSION

In this systematic review, we seek to evaluate the quality of genetic evidence for AIS to better inform research efforts, to ultimately improve the quality of patient care and diagnosis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration #CRD42021243253.

A Decade in Review after Idiopathic Scoliosis Was First Called a Complex Trait-A Tribute to the Late Dr. Yves Cotrel for His Support in Studies of Etiology of Scoliosis

Adolescent Idiopathic Scoliosis (AIS) is a prevalent and important spine disorder in the pediatric age group. An increased family tendency was observed for a long time, but the underlying genetic mechanism was uncertain. In 1999, Dr. Yves Cotrel founded the Cotrel Foundation in the Institut de France, which supported collaboration of international researchers to work together to better understand the etiology of AIS. This new concept of AIS as a complex trait evolved in this setting among researchers who joined the annual Cotrel meetings. It is now over a decade since the first proposal of the complex trait genetic model for AIS. Here, we review in detail the vast information about the genetic and environmental factors in AIS pathogenesis gathered to date. More importantly, new insights into AIS etiology were brought to us through new research data under the perspective of a complex trait. Hopefully, future research directions may lead to better management of AIS, which has a tremendous impact on affected adolescents in terms of both physical growth and psychological development.

Genetic variant of MIR4300HG is associated with progression of adolescent idiopathic scoliosis in a Chinese population

Background

A recent genome-wide association study identified a susceptible locus in MIR4300HG gene that was associated with curve progression of adolescent idiopathic scoliosis (AIS) in the Japanese population. However, the association between the gene and curve progression in other populations remains unclear.

Methods

A cohort of 1952 AIS patients and 2495 healthy controls were included in the case-control analysis. In the case-only analysis, 747 patients were assigned to the progression group and 520 patients were assigned to the non-progression group, respectively. Rs35333564 was genotyped for all the subjects. Paraspinal muscles of 76 patients were collected for the analysis of gene expression. Chi-square test and ANOVA test were used for the intergroup comparison. Pearson correlation analysis was performed to investigate the relationship between the gene expression and curve magnitude.

Results

Variant rs35333564 was significantly associated with the curve severity of AIS (p = 0.025), but not the development of AIS (p = 0.418). Genotype GG was indicated by remarkably lower expression of MIR4300 (p = 0.020) which was significantly correlated with curve magnitude (p = 0.010). As a predicted target gene of MIR4300, the expression of CRTC1 was negatively correlated with MIR4300 expression (p = 0.012, r = −0.287) and positively correlated with curve severity (p = 0.025, r = 0.257).

Conclusions

The association between rs35333564 and curve progression was successfully replicated in a Chinese AIS population. CRTC1 may be the target gene of MIR4300 that plays a role in the curve progression of AIS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02455-w.

Dietary Habits Had No Relationship with Adolescent Idiopathic Scoliosis: Analysis Utilizing Quantitative Data about Dietary Intakes

Although several genetic and environmental factors have been identified as risk factors of adolescent idiopathic scoliosis (AIS), the influence of dietary intake has not been elucidated. We evaluated the association between AIS and dietary habits among female students. Junior high school girls aged 12 to 15 years in the Tokyo metropolitan area who underwent a second school screening for scoliosis were recruited. AIS was diagnosed by orthopedic surgeons specializing in scoliosis, using standing whole spine radiography. Students with a Cobb angle of ≥15° were classified into the AIS group, and others were considered healthy controls. Dietary assessment was performed using a validated diet history questionnaire. Dietary intakes were categorized into quintiles based on distribution, and crude and multivariable odds ratios and 95% confidence intervals for AIS for each quintile category of dietary variable were calculated, with the lowest quintile category used as a reference. In total, 2431 subjects were included in the analysis, and 47.8% of them were diagnosed with AIS. None of the selected nutrients or food groups was significantly associated with AIS. In conclusion, dietary habits may not be associated with AIS.

Adolescent idiopathic scoliosis for the primary care physician: frequently asked questions

PURPOSE OF REVIEW

Provide primary care physicians with the best available evidence to support answers to frequently asked questions by caregivers of patients with adolescent idiopathic scoliosis (AIS).

RECENT FINDINGS

A review of best available evidence shows that schoolbag design and weight are not associated with higher odds of developing AIS. However, patients with AIS are more prone to balance problems with asymmetric backpack carrying and with rising weights. In patients with AIS, the backpack should be worn in a symmetric way and should never exceed 10% of the child's body weight. Although no relationship was found between systematic exercising in general and development of AIS, classical ballet and professional swimming in skeletally immature adolescents were associated to higher odds of having AIS. Since AIS affects adolescent girls mainly, women health issues are of paramount importance in this disease. Except for limited sexual activity and higher need for infertility treatment, patients with AIS perform similar to controls in marriage rates, age at first pregnancy, gestational age, offspring, labor and delivery. Best available evidence shows that adults with AIS diagnosed during adolescence have similar physical activity level compared with controls. In patients with AIS, adults with surgically treated idiopathic scoliosis have slightly lower physical activity level than previously braced and untreated patients.

SUMMARY

Although schoolbag weight isn't associated with higher odds of developing AIS, classical ballet and professional swimming in adolescents are. Except for limited sexual activity, patients with AIS perform similar to controls in remaining women health issues. Adults with AIS diagnosed during adolescence have similar physical activity level compared with controls.

An N-Ethyl-N-Nitrosourea (ENU) Mutagenized Mouse Model for Autosomal Dominant Nonsyndromic Kyphoscoliosis Due to Vertebral Fusion

Kyphosis and scoliosis are common spinal disorders that occur as part of complex syndromes or as nonsyndromic, idiopathic diseases. Familial and twin studies implicate genetic involvement, although the causative genes for idiopathic kyphoscoliosis remain to be identified. To facilitate these studies, we investigated progeny of mice treated with the chemical mutagen N-ethyl-N-nitrosourea (ENU) and assessed them for morphological and radiographic abnormalities. This identified a mouse with kyphoscoliosis due to fused lumbar vertebrae, which was inherited as an autosomal dominant trait; the phenotype was designated as hereditary vertebral fusion (HVF) and the locus as Hvf. Micro-computed tomography (μCT) analysis confirmed the occurrence of nonsyndromic kyphoscoliosis due to fusion of lumbar vertebrae in HVF mice, consistent with a pattern of blocked vertebrae due to failure of segmentation. μCT scans also showed the lumbar vertebral column of HVF mice to have generalized disc narrowing, displacement with compression of the neural spine, and distorted transverse processes. Histology of lumbar vertebrae revealed HVF mice to have irregularly shaped vertebral bodies and displacement of intervertebral discs and ossification centers. Genetic mapping using a panel of single nucleotide polymorphic (SNP) loci arranged in chromosome sets and DNA samples from 23 HVF (eight males and 15 females) mice, localized Hvf to chromosome 4A3 and within a 5-megabase (Mb) region containing nine protein coding genes, two processed transcripts, three microRNAs, five small nuclear RNAs, three large intergenic noncoding RNAs, and 24 pseudogenes. However, genome sequence analysis in this interval did not identify any abnormalities in the coding exons, or exon-intron boundaries of any of these genes. Thus, our studies have established a mouse model for a monogenic form of nonsyndromic kyphoscoliosis due to fusion of lumbar vertebrae, and further identification of the underlying genetic defect will help elucidate the molecular mechanisms involved in kyphoscoliosis. © 2018 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Idiopathic Scoliosis Families Highlight Actin-Based and Microtubule-Based Cellular Projections and Extracellular Matrix in Disease Etiology

Idiopathic scoliosis (IS) is a structural lateral spinal curvature of ≥10° that affects up to 3% of otherwise healthy children and can lead to life-long problems in severe cases. It is well-established that IS is a genetic disorder. Previous studies have identified genes that may contribute to the IS phenotype, but the overall genetic etiology of IS is not well understood. We used exome sequencing to study five multigenerational families with IS. Bioinformatic analyses identified unique and low frequency variants (minor allele frequency ≤5%) that were present in all sequenced members of the family. Across the five families, we identified a total of 270 variants with predicted functional consequences in 246 genes, and found that eight genes were shared by two families. We performed GO term enrichment analyses, with the hypothesis that certain functional annotations or pathways would be enriched in the 246 genes identified in our IS families. Using three complementary programs to complete these analyses, we identified enriched categories that include stereocilia and other actin-based cellular projections, cilia and other microtubule-based cellular projections, and the extracellular matrix (ECM). Our results suggest that there are multiple paths to IS and provide a foundation for future studies of IS pathogenesis.

Etiological Theories of Adolescent Idiopathic Scoliosis: Past and Present

Adolescent idiopathic scoliosis is one of the most common spinal deformities, yet its cause is unknown. Various theories look to biomechanical, neuromuscular, genetic, and environmental origins, yet our understanding of scoliosis etiology is still limited. Determining the cause of a disease is crucial to developing the most effective treatment. Associations made with scoliosis do not necessarily point to causality, and it is difficult to determine whether said associations are primary (playing a role in development) or secondary (develop as a result of scoliosis). Scoliosis is a complex condition with highly variable expression, even among family members, and likely has many causes. These causes could be similar among homogenous groups of AIS patients, or they could be individual. Here, we review the most prevalent theories of scoliosis etiology and recent trends in research.

Concordance for curve type in idiopathic scoliosis among family members

OBJECTIVE:

To evaluate the concordance for the curve pattern, side and levels of the superior apical vertebrae, apex and inferior apical vertebrae of curves in patients and their relatives with idiopathic scoliosis.

METHODS:

Concordance according to the Lenke classification for curve pattern, side and levels of the superior apical vertebrae, apex and inferior apical vertebrae were evaluated comparative and prospectively in 243 pairs of patients and respective relatives with idiopathic scoliosis.

RESULTS:

The family concordance for the curve pattern and side was 51.4% (125 pairs). Among these pairs, the concordance of the levels of the vertebrae was 91.2% (114 pairs). The concordance rate for the curve pattern and side between parents/children was 51.6% and between siblings was 50.0% (p-value= 0.411). The concordance rates of the levels of vertebrae were 86.8% and 95.1%, respectively (p-value = 0.219).

CONCLUSION:

Curve shape in idiopathic scoliosis is related to family and degree of kinship, since the data showed a high concordance for the curve pattern, side and levels of the apical vertebrae and apex between patients and relatives with this deformity. The concordance was higher in those with a closer degree of kinship.Level of Evidence II, Lesser Quality Prospective Study.

Genetics and pathogenesis of idiopathic scoliosis

Idiopathic scoliosis (IS), the most common spinal deformity, affects otherwise healthy children and adolescents during growth. The aetiology is still unknown, although genetic factors are believed to be important. The present review corroborates the understanding of IS as a complex disease with a polygenic background. Presumably IS can be due to a spectrum of genetic risk variants, ranging from very rare or even private to very common. The most promising candidate genes are highlighted.

Understanding the role of the immune system in adolescent idiopathic scoliosis: Immunometabolic CONnections to Scoliosis (ICONS) study protocol

INTRODUCTION

Adolescent idiopathic scoliosis (AIS) affects up to 3% of children around the world. There is limited knowledge of AIS aetiopathogenesis, and this evidence is needed to develop new management strategies. Paraspinal muscle in AIS demonstrates evidence of differential fibrosis based on curve sidedness. Fibrosis is the hallmark of macrophage-driven inflammation and tissue remodelling, yet the mechanisms of fibrosis in paraspinal muscle in AIS are poorly understood.

OBJECTIVES

The primary objective of this study is to determine the influence of curve sidedness on paraspinal muscle inflammation. Secondary objectives include defining the mechanisms of macrophage homing to muscle, and determining muscle-macrophage crosstalk in muscle fibrosis in AIS.

METHODS AND ANALYSIS

This is a cross-sectional study conducted in a tertiary paediatric centre in Hamilton, Ontario, Canada. We will recruit boys and girls, 10-17 years of age, who are having surgery to correct AIS. We will exclude children who have an active infection or are on immunosuppressive therapies within 2 weeks of surgery, smokers and pregnant girls. Paraspinal muscle biopsies will be obtained at the start of surgery. Also, blood and urine samples will be collected from participants, who will fill questionnaires about their lifestyle. Anthropometric measures will also be collected including height, weight, waist and hip circumferences.

ETHICS AND DISSEMINATION

This study has received ethics authorisation by the institutional review board. This work will be published in peer-reviewed journals and will be presented in oral and poster formats at scientific meetings.

DISCUSSION

This study will explore the mechanisms of paraspinal muscle inflammation, remodelling and fibrosis in AIS. This will help identify pathways and molecules as potential therapeutic targets to treat and prevent AIS. It may also yield markers that predict scoliosis progression and response to treatment in these children.

Bracing and exercise-based treatment for idiopathic scoliosis

BACKGROUND

Various conservative therapies are available for treating adolescent idiopathic scoliosis (AIS), however, the disparities between them and the evidence of their efficacy and effectiveness is still unclear.

OBJECTIVES

To evaluate the effectiveness of different conservative treatments on AIS.

METHODS

A literature-based narrative review of the English language medical literature.

RESULTS AND CONCLUSIONS

The most appropriate treatment for each patient should be chosen individually and based on various parameters. Bracing has been found to be a most effective conservative treatment for AIS. There is limited evidence that specific physical exercises also an effective intervention for AIS. Exercise-based physical therapy, if correctly administered, can prevent a worsening of the curve and may decrease need for bracing. In addition, physical exercises were found to be the only treatment improving respiratory function. Combining bracing with exercise increases treatment efficacy compared with a single treatment. Additional, well-designed and good quality studies are required to assess the effectiveness of different conservative methods in treating AIS.

Idiopathic Scoliosis Prevalence Is 5 Times Less in Roma Than Greek Children and Adolescents

STUDY DESIGN

Serial screening of Roma children for idiopathic scoliosis.

OBJECTIVE

To confirm or reject the observation that the prevalence of scoliosis is reduced in the Roma population and possibly to explain it.

MATERIALS AND METHODS

The authors conducted serial screening for idiopathic scoliosis of 1,034 indigenous Roma children (542 boys and 492 girls), aged 4-18 years (857 children were aged 8-18 years) from 1997 to 2011. Age, height, weight, body mass index, years of schooling, and menarche for girls were recorded. Children were clinically examined for body asymmetries and a standing posteroanterior spinal radiograph was obtained in selected cases.

RESULTS

Sixty Roma children (6%) had clinical humps. Single humps, according to location, were mostly benign and not related to progressive scoliotic curves. In children with right thoracic humps a left lumbar component could be overlooked. Of 60 children, only 4 (3 girls and 1 boy) with right thoracic and left lumbar or thoracolumbar humps had true progressive scoliotic curves with greater than 10° Cobb angle (prevalence rate, 0.35%). This is 5 times less than the rate of 1.5% in Greek children. One of these 4 children was young and had possible congenital scoliosis; the other 3 were early adolescents.

CONCLUSIONS

A substantial difference in the prevalence of scoliosis between Roma and Greek children was documented. The usual percentage of adolescent scoliosis found in the Greek population (approximately 15-17 cases/1,000 children) was not seen in this sample of Roma children.

Exome sequencing identifies a rare HSPG2 variant associated with familial idiopathic scoliosis

Idiopathic scoliosis occurs in 3% of individuals and has an unknown etiology. The objective of this study was to identify rare variants that contribute to the etiology of idiopathic scoliosis by using exome sequencing in a multigenerational family with idiopathic scoliosis. Exome sequencing was completed for three members of this multigenerational family with idiopathic scoliosis, resulting in the identification of a variant in the HSPG2 gene as a potential contributor to the phenotype. The HSPG2 gene was sequenced in a separate cohort of 100 unrelated individuals affected with idiopathic scoliosis and also was examined in an independent idiopathic scoliosis population. The exome sequencing and subsequent bioinformatics filtering resulted in 16 potentially damaging and rare coding variants. One of these variants, p.Asn786Ser, is located in the HSPG2 gene. The variant p.Asn786Ser also is overrepresented in a larger cohort of idiopathic scoliosis cases compared with a control population (P = 0.024). Furthermore, we identified additional rare HSPG2 variants that are predicted to be damaging in two independent cohorts of individuals with idiopathic scoliosis. The HSPG2 gene encodes for a ubiquitous multifunctional protein within the extracellular matrix in which loss of function mutation are known to result in a musculoskeletal phenotype in both mouse and humans. Based on these results, we conclude that rare variants in the HSPG2 gene potentially contribute to the idiopathic scoliosis phenotype in a subset of patients with idiopathic scoliosis. Further studies must be completed to confirm the effect of the HSPG2 gene on the idiopathic scoliosis phenotype.

Selective estrogen receptor modulation prevents scoliotic curve progression: radiologic and histomorphometric study on a bipedal C57Bl6 mice model

PURPOSE

Previous work has suggested that progression of experimental scoliotic curves in pinealectomized chicken and bipedal C57BL6 mice models may be prevented and reversed with Tamoxifen treatment. Raloxifene is another Selective Estrogen Receptor Modulator (SERM) with estrogen agonist effects on bone and increases bone density but with fewer side effects on humans. To investigate whether scoliosis progression in bipedal C57Bl6 mice model could be prevented with SERM treatment and the mechanisms associated with this effect.

METHODS

Eighty C57BL6 mice were rendered bipedal and divided into Tamoxifen (TMX), Raloxifene (RLX) and control groups. TMX and RLX groups received orally administered TMX and RLX for 40 weeks. Anteroposterior X-ray imaging and histomorphometric analysis (at 20th and 40th weeks) were performed.

RESULTS

At 20th week, TMX and RLX groups displayed higher rates (p = 0.033, p = 0.029) and larger curve magnitudes (p = 0.018). At 40th week, curve rates were similar between the groups but the curve magnitudes in TMX and RLX groups were smaller (p = 0.001). Histomorphometry revealed that treated animals had higher trabecular density (p = 0.04), lower total intervertebral disc (p = 0.038) and growth plate volumes (p = 0.005) and smaller vertebral bodies (p = 0.016).

CONCLUSIONS

Treatment with TMX or RLX did not reduce the incidence of scoliosis but decreased the curve magnitudes at 40 weeks. The underlying mechanism associated with the decrease in curve magnitudes may be the early maturation of growth plates, thereby possible deceleration of the growth rate of the vertebral column and increase in bone density. RLX is as effective as TMX in preventing the progression of scoliotic curves in melatonin deficient bipedal mice.

Family history and its association to curve size and treatment in 1,463 patients with idiopathic scoliosis

PURPOSE

To study family history in relation to curve severity, gender, age at diagnosis and treatment in idiopathic scoliosis.

METHODS

A self-assessment questionnaire on family history of scoliosis was administered to 1,463 untreated, brace or surgically treated idiopathic scoliosis patients.

RESULTS

Out of the 1,463 patients, 51 % had one or more relatives with scoliosis. There was no significant difference between females and males, nor between juvenile and adolescent study participants in this respect (p = 0.939 and 0.110, respectively). There was a significant difference in maximum curve size between patients with one or more relatives with scoliosis (median 35°, interquartile range 25) and patients without any relative with scoliosis (median 32°, interquartile range 23) (p = 0.022). When stratifying patients according to treatment (observation, brace treatment or surgery), we found that it was more common to have a relative with scoliosis among the treated patients (p = 0.011). The OR for being treated was 1.32 (95% CI 1.06-1.64) when the patient had a relative with scoliosis, compared to not having.

CONCLUSIONS

Larger curve sizes were found in patients with a family history of scoliosis than in the ones without. No relation between family history and gender or between family history and age at onset of idiopathic scoliosis was found. Although the presence of a family history of scoliosis may not be a strong prognostic risk factor, it indicates that these patients are at higher risk of developing a more severe curve.

Familial or Sporadic Idiopathic Scoliosis - classification based on artificial neural network and GAPDH and ACTB transcription profile

BACKGROUND

Importance of hereditary factors in the etiology of Idiopathic Scoliosis is widely accepted. In clinical practice some of the IS patients present with positive familial history of the deformity and some do not. Traditionally about 90% of patients have been considered as sporadic cases without familial recurrence. However the exact proportion of Familial and Sporadic Idiopathic Scoliosis is still unknown. Housekeeping genes encode proteins that are usually essential for the maintenance of basic cellular functions. ACTB and GAPDH are two housekeeping genes encoding respectively a cytoskeletal protein β-actin, and glyceraldehyde-3-phosphate dehydrogenase, an enzyme of glycolysis. Although their expression levels can fluctuate between different tissues and persons, human housekeeping genes seem to exhibit a preserved tissue-wide expression ranking order. It was hypothesized that expression ranking order of two representative housekeeping genes ACTB and GAPDH might be disturbed in the tissues of patients with Familial Idiopathic Scoliosis (with positive family history of idiopathic scoliosis) opposed to the patients with no family members affected (Sporadic Idiopathic Scoliosis). An artificial neural network (ANN) was developed that could serve to differentiate between familial and sporadic cases of idiopathic scoliosis based on the expression levels of ACTB and GAPDH in different tissues of scoliotic patients. The aim of the study was to investigate whether the expression levels of ACTB and GAPDH in different tissues of idiopathic scoliosis patients could be used as a source of data for specially developed artificial neural network in order to predict the positive family history of index patient.

RESULTS

The comparison of developed models showed, that the most satisfactory classification accuracy was achieved for ANN model with 18 nodes in the first hidden layer and 16 nodes in the second hidden layer. The classification accuracy for positive Idiopathic Scoliosis anamnesis only with the expression measurements of ACTB and GAPDH with the use of ANN based on 6-18-16-1 architecture was 8 of 9 (88%). Only in one case the prediction was ambiguous.

CONCLUSIONS

Specially designed artificial neural network model proved possible association between expression level of ACTB, GAPDH and positive familial history of Idiopathic Scoliosis.

Genetic epidemiology and heritability of AIS: A study of 415 Chinese female patients

Recent familial segregation studies supported a multifactorial genetic model for the etiology of adolescent idiopathic scoliosis (AIS). However, the extent of quantitative genetic effects, such as heritability, have not been fully evaluated. This genetic epidemiology study examined the sibling recurrent risk and heritability of AIS in first-degree relatives of 415 Chinese female patients, which is up to now the largest cohort. They were first diagnosed by community screening program and compared to 203 age-matched normal controls. Out of the total 531 sibs of AIS cases, 94 sibs had scoliosis (sibling recurrence risk = 17.7%). The prevalence of AIS among male and female sibs of an index case were 11.5% (95% CI = 7.5-15.5) and 23.0% (95% CI = 18.1-27.9), respectively. Female sibs of an index case had an increased risk of 8.9-fold (95% CI = 3.2-34.4) for developing AIS. These recurrent risks were significantly higher than the risk in the control group (p < 0.0001). Overall, heritability was estimated to be 87.5 ± 11.1%. The results confirmed the prevailing impression of strong genetic influence on the risk of AIS. Here we provided a large-scale study for the genetic aggregation estimates in an Asian population for the first time. The finding also positioned AIS among other common disease or complex traits with a high heritability.

Adolescent idiopathic scoliosis (AIS), environment, exposome and epigenetics: a molecular perspective of postnatal normal spinal growth and the etiopathogenesis of AIS with consideration of a network approach and possible implications for medical therapy

Genetic factors are believed to play an important role in the etiology of adolescent idiopathic scoliosis (AIS). Discordant findings for monozygotic (MZ) twins with AIS show that environmental factors including different intrauterine environments are important in etiology, but what these environmental factors may be is unknown. Recent evidence for common chronic non-communicable diseases suggests epigenetic differences may underlie MZ twin discordance, and be the link between environmental factors and phenotypic differences. DNA methylation is one important epigenetic mechanism operating at the interface between genome and environment to regulate phenotypic plasticity with a complex regulation across the genome during the first decade of life. The word exposome refers to the totality of environmental exposures from conception onwards, comprising factors in external and internal environments. The word exposome is used here also in relation to physiologic and etiopathogenetic factors that affect normal spinal growth and may induce the deformity of AIS. In normal postnatal spinal growth we propose a new term and concept, physiologic growth-plate exposome for the normal processes particularly of the internal environments that may have epigenetic effects on growth plates of vertebrae. In AIS, we propose a new term and concept pathophysiologic scoliogenic exposome for the abnormal processes in molecular pathways particularly of the internal environment currently expressed as etiopathogenetic hypotheses; these are suggested to have deforming effects on the growth plates of vertebrae at cell, tissue, structure and/or organ levels that are considered to be epigenetic. New research is required for chromatin modifications including DNA methylation in AIS subjects and vertebral growth plates excised at surgery. In addition, consideration is needed for a possible network approach to etiopathogenesis by constructing AIS diseasomes. These approaches may lead through screening, genetic, epigenetic, biochemical, metabolic phenotypes and pharmacogenomic research to identify susceptible individuals at risk and modulate abnormal molecular pathways of AIS. The potential of epigenetic-based medical therapy for AIS cannot be assessed at present, and must await new research derived from the evaluation of epigenetic concepts of spinal growth in health and deformity. The tenets outlined here for AIS are applicable to other musculoskeletal growth disorders including infantile and juvenile idiopathic scoliosis.

Heritability of scoliosis

PURPOSE

To estimate the heritability of scoliosis in the Swedish Twin Registry.

METHODS

Self-reported data on scoliosis from 64,578 twins in the Swedish Twin Registry were analysed. Prevalence, pair- and probandwise concordances and tetrachoric correlations in mono- and dizygotic same-sex twins were calculated. The relative importance of genetic variance, i.e. the heritability, and unique and shared environmental variance was estimated using structural equation modelling in Mx software. In addition, all twins in the twin registry were matched against the Swedish Inpatient Register on the primary diagnosis idiopathic scoliosis.

RESULTS

The prevalence of scoliosis was 4%. Pair- and probandwise concordance was 0.11/0.17 for mono- and 0.04/0.08 for same-sex dizygotic twins. The tetrachoric correlation (95% CI) was 0.41 (0.33-0.49) in mono- and 0.18 (0.09-0.29) in dizygotic twins. The most favourable model in the Mx analyses estimated the additive genetic effects (95% CI) to 0.38 (0.18-0.46) and the unique environmental effects to 0.62 (0.54-0.70). Shared environmental effects were not significant. The pairwise/probandwise concordance for idiopathic scoliosis in the Swedish Inpatient Register was 0.08/0.15 for monozygotic and zero/zero for same-sex dizygotic twins.

CONCLUSION

Using self-reported data on scoliosis from the Swedish Twin Registry, we estimate that 38% of the variance in the liability to develop scoliosis is due to additive genetic effects and 62% to unique environmental effects. This is the first study of sufficient size to make heritability estimates of scoliosis.

Concordance for curve type in familial idiopathic scoliosis: a survey of one hundred families

STUDY DESIGN

Prospective comparative study on 100 patients with positive family history for idiopathic scoliosis.

OBJECTIVE

To evaluate the concordance rate for curve pattern and side in family members with idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

The pathogenesis of idiopathic scoliosis has been the subject of extensive research. It is termed multifactorial with a genetic component. Similar curve shape has been reported in twins with idiopathic scoliosis.

METHODS

We included prospectively 100 patients with idiopathic scoliosis when a relative of them was also affected with idiopathic scoliosis, and spine radiographs were available for both. Concordance for curve pattern by Lenke classification and side between family members was analyzed.

RESULTS

Familial concordance rate for curve pattern and side was 66% (95% confidence interval, 57-75), whereas the expected random concordance rate was 26% (95% confidence interval, 17-34). The affected relative was in 27 cases a sibling, in 32 cases a parent, in 1 case an uncle, in 2 cases a cousin, in 2 cases a half sister, in 2 cases a grandmother. Concordance rate was 65% (27/42) in siblings' pairs and 67% (32/48) in parents/child's pairs.

CONCLUSION

We report a high concordance rate for curve pattern and side between relatives with idiopathic scoliosis. Curve shape is likely to be genetically determined in familial scoliosis. It seems important that curve type is documented and considered in future genetic studies.

Adolescent idiopathic scoliosis in athletes: is there a connection?

The potential relationship between adolescent idiopathic scoliosis (AIS) and sports is rather vague. Sports have often been considered to be a causative factor of, or a treatment option for the former, particularly among adolescent athletes who are engaged in certain athletic activities. The highly repetitive nature of sports, amenorrhea, exercise-related exerted stress on the immature spine of professional adolescent athletes, and the joint laxity that may coexist during adolescence, have also been associated with an increased incidence of AIS. The purpose of this article is to discuss the potential connection between sports and AIS by reviewing the existing literature.

Variações na apresentação fenotípica da escoliose idiopática do adolescente

OBJETIVO: discutir quais elementos, de acordo com a literatura, são responsáveis pela discordância fenotípica em gêmeos monozigóticos. MÉTODOS: foram levantados os dados ambulatoriais de um par de gêmeas monozigóticas, que incluíram: idade no momento do diagnóstico, tipo de curva, ângulo de Cobb da deformidade na consulta inicial, início do tratamento e último acompanhamento, ápice da curva e ângulo de Cobb aferido nas imagens radiográficas em perfil. RESULTADOS: criança I: curva principal lombar à esquerda, com ângulo de Cobb entre T11-L4 de 17°, e curva torácica direita entre T5-T11 de 14°. Os ápices encontravam-se no disco L1-L2 e na vértebra T8, respectivamente. Um ano depois, se detectou progressão significativa da deformidade, com a curva lombar evoluindo para 24° (T11-L4) e a curva torácica para 23° (T5-T11). Criança II: curva toracolombar de pequena magnitude à direita, com ângulo de Cobb entre T9 e L3 de 18°. O ápice situava-se na vértebra de T12. Um ano depois, observou-se aumento da curva, com o ângulo de Cobb progredindo para 40°. CONCLUSÃO: não obstante a evidência da origem genética para o desenvolvimento da escoliose, admite-se a influência de outros fatores para sua manifestação e progressão. Na literatura, encontram-se algumas explicações para o desenvolvimento da doença, referentes à deficiência de tecidos estruturais encontrada em síndromes e condições específicas, crescimento assimétrico dos membros e tronco, alterações da configuração sagital da coluna vertebral e fatores ligados à natureza, como alimentação.

The role of exercising in a pair of female monozygotic (high-class athletes) twins discordant for adolescent idiopathic scoliosis

STUDY DESIGN

The report of 2 cases and review of the literature.

OBJECTIVE

To report the cases of a pair of female monozygotic (high-class athletes) twins discordant for adolescent idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

The relation between scoliosis and exercising is rather unclear. The latter has often been considered both as a therapeutic means and a causative factor of the former. The existence of genetic predisposition in the development of adolescent idiopathic scoliosis is commonly accepted. According to the best of our knowledge, this is the first report of a pair of female monozygotic (high-class athletes) twins, discordant for adolescent idiopathic scoliosis. METHODS.: A pair of 13.5-year-old female monozygotic twins, high-class level athletes of synchronized swimming, was clinically examined during a school screening program. Both girls were observed in the standing erect position for asymmetries of the lateral contours of the trunk, shoulders, and scapulas and their limb's length was measured. The "forward bending test" was performed to determine the existence of rib hump asymmetry.

RESULTS

One of the sisters was considered to be suspicious of suffering from scoliosis. The radiologic evaluation that followed confirmed the existence of adolescent idiopathic scoliosis (left thoracolumbar curve of 32 degrees as measured by the Cobb angle). The clinical and radiologic evaluation of her sibling failed to reveal the existence of any spinal deformity.

CONCLUSION

Adolescent idiopathic scoliosis seems to be a multifactorial skeletal disorder. The role of exercising and heredity in its development remain controversial.

Non-genetic expression of adolescent idiopathic scoliosis: a case report and review of the literature

Treating children with idiopathic scoliosis can amaze someone at the many different ways in which the deformity can present. Most authors state that genetics stipulates the course of adolescent idiopathic scoliosis. This is mainly based on the high concordance in monozygotic twins. However, there is indication that environmental factors have influences on adolescent idiopathic scoliosis. This is the first report in which a monozygotic twin pair is described concordant for idiopathic scoliosis but with different apical levels, magnitudes and age at detection of scoliosis which stresses the importance of environmental factors.

Adolescent idiopathic scoliosis in twins: a population-based survey

STUDY DESIGN

A questionnaire-based identification of adolescent idiopathic scoliosis (AIS) patients in a twin cohort.

OBJECTIVE

The purpose of this study was to establish a scoliosis twin cohort to provide data on the heritability of AIS.

SUMMARY OF BACKGROUND DATA

The etiology of AIS is still unclear, and the true mode of inheritance has yet to be established. Concordance rates in monozygotic twins have been reported to be between 0.73 and 0.92, and in dizygotic twins between 0.36 and 0.63. Studies on concordance in twin pairs provide a basis for analyzing the influence of genetic versus environmental factors.

METHODS

All 46,418 twins registered in the Danish Twin Registry born from 1931 to 1982 were sent a questionnaire, which included questions about scoliosis. A total of 34,944 (75.3%) representing 23,204 pairs returned the questionnaire.

RESULTS

A subgroup of 220 subjects considered to have AIS was identified, thus giving a prevalence of 1.05%. The concordant twin pairs were all monozygotic. Pairwise, the concordance rate was 0.13 for monozygotic and zero for dizygotic twin pairs; proband-wise concordance was 0.25 for monozygotic and zero for dizygotic pairs. The concordance of monozygotic and dizygotic pairs was significantly different (P < 0.05).

CONCLUSION

We have found evidence for a genetic etiology in AIS, but the risk of developing scoliosis in 1 twin whose other twin has scoliosis is smaller than believed up until now.

Idiopathic scoliosis: how much of a genetic disorder? Report of five pairs of monozygotic twins

PURPOSE

The role of genetic factors in the development of Adolescent Idiopathic Scoliosis (AIS) has been well documented; however, reports of the specific mode of genetic inheritance are inconclusive. These facts, combined with the phenotypic variability of this disorder, suggest that the genetic expression of idiopathic scoliosis may be dependent on multiple factors and genetic interactions. However, it seems questionable whether there is evidence for a genetic aetiology for adolescent idiopathic scoliosis, when in monozygotic twins there is no 100% concordance of the symptoms and prognosis.

METHODS

Five pairs of monozygotic tested twins with the diagnosis of AIS were presented in the outpatient practice of the author. There was no history of scoliosis in any other member of the family.

RESULTS

Pair 1: Growth is still left in both girls, however prognosis is totally different. The progression factor of the first girl was 1.75 and so she has a risk of >65% for curve progression, Cobb angle 40. Progression factor of the second girl was 0.56 and so she has a risk of <5% for curve progression, Cobb angle 18. Pair 2: Both girls presented with Risser 4. Cobb angle was 55 degrees in one of the twins (progression factor: 3.1; risk for progression >95%) and 220 in the other (progression factor: 0.7; risk for progression <5%). Curve pattern was thoracic in the first, double major in the second girl. Pair 3: Two monozygotic tested boys with similar bad prognoses and similar curve pattern and similar degrees of curvature (90 and 100 degrees). Pair 4: Two not tested girls with similar benign prognoses and similar curve patterns (18 and 22 degrees). Pair 5: Two monozygotic tested girls with different prognoses and similar curve patterns (26 and 49 degrees).

CONCLUSIONS

Different curve patterns in two of the five pairs of twins as well as different prognoses can be discussed as phenotypic variability of AIS, however the findings from the other three pairs may be interpreted in the way that genetic factors play a role in the aetiology of AIS.

Evidence of a linkage between matrilin-1 gene (MATN1) and idiopathic scoliosis

Background

In a previous study, a number of genes, associated with spine musculoskeletal deformity phenotypes in mouse and in synteny between mouse and man, were identified as candidate genes for IS. Among these genes, MATN1, which carries a polymorphic microsatellite marker within its sequence, was selected for a linkage analysis. MATN1 is localised at 1p35 and is mainly expressed in cartilage. The objective of this study was to assess a linkage disequilibrium between the matrilin-1 (MATN1) gene and the idiopathic scoliosis (IS).

Methods

The genetic study was conducted on a population of 81 trios, each consistent of a daughter/son affected by idiopathic scoliosis (IS) and both parents. In all trios components, the region of MATN1 gene containing the microsatellite marker was amplified by a polymerase chain reaction. The amplicons were analysed by a DNA sequencer-genotyper. The statistical linkage analysis was performed using the extended transmission/disequilibrium test.

Results

Three microsatellite polymorphisms, respectively consisting of 103 bp, 101 bp and 99 bp, were identified. ETDT evidenced a significant preferential transmission for the 103 bp allele (Chi-square = 5.058, df = 1, P = 0.024)

Conclusion

The results suggest that the familial idiopathic scoliosis is associated to the MATN1 gene.

Scoliosis in association with infantile hypophosphatasia: a case study in two siblings

STUDY DESIGN

A case study of scoliosis in two siblings with infantile hypophosphatasia and review of literature are presented.

OBJECTIVES

To report the rare occurrence of scoliosis in two siblings with infantile hypophosphatasia and detail problems in the surgical management of scoliosis in this rare disease.

SUMMARY OF BACKGROUND DATA

To the authors' knowledge there is only one reported case of scoliosis in infantile hypophosphatasia. However, there is no report describing the nature of the curve, its progression, or the surgical management of scoliosis in infantile hypophosphatasia.

METHODS

The first sibling was diagnosed shortly after birth to have scoliosis that progressed rapidly despite brace treatment. At 4 years, he underwent anterior convex arthrodesis and posterior T6-L1 Luque trolley stabilization. Because of further curve progression, he had to undergo corrective anterior and posterior osteotomies, stabilization, and fusion at 11 years of age. The second sibling was diagnosed to have scoliosis at the age of 3 years and underwent anterior thoracoscopic release and posterior Luque trolley stabilization.

RESULTS

The first sibling with a mild form of infantile hypophosphatasia had to undergo multiple procedures to attain fusion and arrest of curve progression. The second sibling with a severe variety of infantile hypophosphatasia surprisingly attained a spontaneous fusion of the curve following the initial correction and stabilization with no further progression at 9-year follow-up.

CONCLUSIONS

Curve progression and fusion rates following scoliosis correction are not related to the disease severity or biochemical findings. These rapidly progressive curves are amenable to surgical correction despite the unfavorable metabolic nature of the disease. Hypercalcemia and seizures responding to pyridoxine are complications in the postoperative period of which the surgeon should be aware.

A comparison of the microarchitectural bone adaptations of the concave and convex thoracic spinal facets in idiopathic scoliosis

BACKGROUND

A limited number of studies have assessed the changes in bone microarchitecture in spinal facets with use of light microscopy but not with use of electron microscopy techniques. The purpose of this study was to analyze the facets in patients with scoliosis to determine whether there are differences in the bone microarchitecture of contralateral facets at the same anatomic level.

METHODS

In eight patients undergoing posterior spinal arthrodesis for the treatment of idiopathic scoliosis, biopsy specimens of facet pairs at matched anatomic levels were obtained from three locations: (1). the curve apex, (2). one level cephalad to the apex, and (3). one level caudad to the apex. The facets were analyzed for cortical bone porosity and thickness with use of scanning electron microscopy and National Institutes of Health imaging software. The concave and convex facets were compared with use of a paired t test.

RESULTS

The mean porosity (and standard deviation) for the concave and convex facets was 16.5% +/- 5.8% and 24.1% +/- 6.2%, respectively. Those on the convex side were significantly more porous than those on the concave side (p <or= 0.03). The mean cortical width for the concave and convex facets was 798 +/- 266 microm and 377 +/- 124 micro m, respectively. The concave facets had a significantly thicker cortex than did the convex facets (p < 0.01).

CONCLUSIONS

These results suggest that scoliotic deformities apply eccentric forces to spinal facets and that the concave and convex portions of the curve are subject to compression and tension forces, respectively. This analysis complements previous investigations of bone microarchitecture in animal models with use of a known compression-tension environment, and it suggests that the spinal facets remodel in a manner consistent with Wolff's law.

SNTG1, the gene encoding gamma1-syntrophin: a candidate gene for idiopathic scoliosis

Idiopathic scoliosis (IS) affects approximately 2%-3% of the population and has a heritable component. The genetics of this disorder are complex. Here, we describe a family in which a pericentric inversion of chromosome 8 co-segregates with IS. We have used fluorescence in situ hybridization to identify cloned DNAs that span the breakpoints on the two arms of the chromosome. We have identified a bacterial artificial chromosome (BAC) of 150 kb that crosses the q-arm breakpoint and a BAC of 120 kb that crosses the p-arm breakpoint. The complete genomic DNA sequence of these BACs has been analyzed to identify candidate genes and to localize further the precise breakpoints. This has revealed that the p-arm break does not interrupt any known gene and occurs in a region of highly repetitive sequence elements. On the q-arm, the break occurs between exons 10 and 11 of the gamma-1 syntrophin (SNTG1) gene. Syntrophins are a group of cytoplasmic peripheral membrane proteins that associate directly with dystrophin, the Duchenne muscular dystrophy gene; gamma1-syntrophin has been shown to be a neuronal cell-specific protein. Mutational analysis of SNTG1 exons in 152 sporadic IS patients has revealed a 6-bp deletion in exon 10 of SNTG1 in one patient and a 2-bp insertion/deletion mutation occurring in a polypyrimidine tract of intronic sequence 20 bases upstream of the SNTG1 exon 5 splice site in two patients. These changes were not seen in a screen of 480 control chromosomes. Genomic DNAs from seven affected individuals within the family of a patient carrying the 6-bp deletion were typed to determine whether the alteration co-segregated with IS. The deletion was only observed in five out of these seven individuals. Thus, although genetic heterogeneity or multiple alleles cannot be ruled out, the 6-bp deletion does not consistently co-segregate with the disease in this family.

Allelic variants of human melatonin 1A receptor in patients with familial adolescent idiopathic scoliosis

STUDY DESIGN

A genetic study of patients with familial adolescent idiopathic scoliosis.

OBJECTIVES

The purpose of this study was to evaluate the evidence for linkage on chromosome 4q and determine whether mutations in the gene coding for melatonin receptor are present.

SUMMARY OF BACKGROUND DATA

Adolescent idiopathic scoliosis is the most common spine deformity arising during childhood, but its cause remains unknown. The fact that adolescent idiopathic scoliosis is often seen in several members of the same family strongly suggests a genetic factor. Recent work by Wise et al provides evidence for linkage of adolescent idiopathic scoliosis at several different chromosome sites, including 4q. In addition, there is some evidence that adolescent idiopathic scoliosis may be related to a disturbance in melatonin metabolism, and the human melatonin-1A receptor is known to be located on chromosome 4q.

METHODS

Probands having clinically relevant idiopathic scoliosis (Cobb angle >30 degrees) and their relatives were identified. Radiographic confirmation was required for a positive diagnosis. Linkage analysis was performed with 15 microsatellite markers of chromosome 4q spaced at approximately 10-cM resolution and 5 microsatellite markers surrounding the site for human melatonin receptor. The gene for human melatonin receptor was screened for mutations in the coding region using genomic DNA samples by single-strand conformational polymorphism analysis. Amplimers showing a band shift were reamplified and sequenced bidirectionally.

RESULTS

There was no evidence for linkage at chromosome 4q in this study population. Twenty-nine individuals demonstrated aberrant single-strand conformation polymorphism band patterns, and sequence evaluation demonstrated six genetic polymorphisms for the gene for human melatonin receptor. These genetic variations were found in both affected and nonaffected individuals, and there was no correlation between gene variants and the phenotype for adolescent idiopathic scoliosis.

CONCLUSIONS

The results of this study demonstrated no evidence of linkage to chromosome 4q and no mutations in the coding region of the gene for human melatonin receptor. The identification of variants in the human melatonin receptor could provide a useful tool for testing the gene in the predisposition to various other melatonin-related disorders and for clarifying the role of melatonin in adolescent idiopathic scoliosis.

Curve characteristics in monozygotic twins with adolescent idiopathic scoliosis: 3 new twin pairs and a review of the literature

Most authors state that there is strong evidence for a genetic origin of adolescent idiopathic scoliosis (AIS). This conclusion is mainly based on the fact that the rate of concordance for AIS in monozygotic twins is significantly higher than that in dizygotic twins. However, it is of interest to determine whether all elements of scoliosis formation are genetically predetermined. If this were the case, there would perhaps be less place for closed treatment. We surveyed the literature for monozygotic twin pairs in which both members suffered from idiopathic scoliosis and added 3 pairs from our own patient group. The total group consisted of 32 twin pairs. We found that gender, direction of the convexity, the level of the apex and the kyphotic angle were determined more by genetic factors than the lateral Cobb angle of the scoliotic curve. This suggests that variations in the environment may affect the curve patterns in monozygotic twins.

Changing curve pattern in infantile idiopathic scoliosis: family report with a follow-up of 15 years

STUDY DESIGN

The authors monitored a father and his six children, all of whom had idiopathic scoliosis for more than 13 years.

OBJECTIVE

To analyze the similarities and differences in curve pattern between the family members.

SUMMARY OF BACKGROUND DATA

The etiology and pathogenesis of idiopathic scoliosis are not well understood. Genetic factors play an important role, as is shown by the high concordance in monozygotic twins.

METHODS

Radiographs from all family members were analyzed. Location and direction of the curve, Cobb angle, location of the apex, and rib-vertebra angle difference were compared.

RESULTS

A father and his six children had idiopathic scoliosis. The curves differed within the family and changed during follow-up. The father had a left convex thoracic scoliosis of 42 degrees. Only three of the children had a curve of similar severity, and only four children had a left convex thoracic scoliosis. In three children the curve pattern changed during follow-up.

CONCLUSIONS

This report of idiopathic scoliosis in a father and six children supports the present theories on a genetic origin of the disorder but also stresses the importance of dynamic processes in the development of scoliosis.

The association between idiopathic scoliosis and the number of acquired melanocytic nevi

BACKGROUND

Several syndromes in which melanocytic nevi and scoliosis were present in the same patient have been described. No control study has been made to date to determine whether there is a relationship between these disorders.

OBJECTIVE

We attempted to demonstrate the association between acquired melanocytic nevi (AMN) and idiopathic scoliosis (IS).

METHODS

We studied 93 patients with IS, aged 10 to 18 years, from our hospital. Controls were randomly selected from 2 schools; Adam's forward bending test was used to exclude persons with clinical scoliosis, and the control group finally comprised 101 pupils. An observational, cross-sectional study was done. All AMN 2 mm or larger observed on the body were counted by one dermatologist. Other variables reported as risk factors in the number of nevi were also considered. Reliability of AMN counts was previously demonstrated.

RESULTS

The median number of AMN was 18 (range, 10-42) in the IS group and 8 (range, 3-13) in controls (P <.001). The persons with scoliosis had more non-AMN dermatologic lesions than the controls (P <.05). Light phenotype correlated with many AMN. On multivariate analysis only scoliosis and age accounted independently for the number of AMN.

CONCLUSION

IS is associated with many AMN. Multiple AMN may become a diagnostic marker for IS, and these two malformations might constitute a syndromic association.

Idiopathic scoliosis: the relation between the vertebral canal and the vertebral bodies

STUDY DESIGN

The axial length of the vertebral canal and the anterior aspect of the vertebrae were measured in 36 skeletons, 15 with probable idiopathic scoliosis.

OBJECTIVES

To compare the discrepancy in length of the vertebral canal and the anterior spinal column in skeletons having probable idiopathic scoliosis with the degree of deformity.

SUMMARY AND BACKGROUND DATA

In idiopathic scoliosis, the vertebral bodies rotate toward the convexity of the curve, whereas the vertebral canal tends to retain a midline position. The vertebral canal therefore will be relatively short. The degree of shortening has not been described previously, nor its relation with the degree of deformity.

METHODS

The axial length of the vertebral canal and the anterior aspect of the vertebral bodies were measured in 36 skeletons: 8 with normal spines, 13 with kyphosis, and 15 with probable idiopathic scoliosis. The relative shortening in the scoliotic spines was correlated with the Cobb angle and the degree of rotation.

RESULTS

No significant difference in length was found between the vertebral canal and the vertebral column in the normal spines. The kyphotic spines had canals significantly longer than the vertebral length (P<0.025). All but one of the scoliotic spines had short vertebral canals (P<0.01). The degree of discrepancy was related to the Cobb angle (r = -0.50; P< 0.05), and particularly to the degree of rotation (r = -0.88; P< 0.001).

CONCLUSIONS

The findings have surgical and etiologic implications. The results are consistent with a conceivable hypothesis that in some patients with idiopathic scoliosis, there may be impaired growth in the length of the spinal cord, the posterior elements are tethered, and as the vertebral bodies continue to grow, they become lordotic and then rotate.