Genetic association study of growth hormone receptor and idiopathic scoliosis

Investigating the Differential Circulating microRNA Expression in Adolescent Females with Severe Idiopathic Scoliosis: A Proof-of-Concept Observational Clinical Study

Adolescent Idiopathic Scoliosis (AIS) is the most common form of three-dimensional spinal disorder in adolescents between the ages of 10 and 18 years of age, most commonly diagnosed in young women when severe disease occurs. Patients with AIS are characterized by abnormal skeletal growth and reduced bone mineral density. The etiology of AIS is thought to be multifactorial, involving both environmental and genetic factors, but to date, it is still unknown. Therefore, it is crucial to further investigate the molecular pathogenesis of AIS and to identify biomarkers useful for predicting curve progression. In this perspective, the relative abundance of a panel of microRNAs (miRNAs) was analyzed in the plasma of 20 AIS patients and 10 healthy controls (HC). The data revealed a significant group of circulating miRNAs dysregulated in AIS patients compared to HC. Further bioinformatic analyses evidenced a more restricted expression of some miRNAs exclusively in severe AIS females. These include some members of the miR-30 family, which are considered promising regulators for treating bone diseases. We demonstrated circulating extracellular vesicles (EVs) from severe AIS females contained miR-30 family members and decreased the osteogenic differentiation of mesenchymal stem cells. Proteomic analysis of EVs highlighted the expression of proteins associated with orthopedic disease. This study provides preliminary evidence of a miRNAs signature potentially associated with severe female AIS and suggests the corresponding vesicular component may affect cellular mechanisms crucial in AIS, opening the scenario for in-depth studies on prognostic differences related to gender and grade.

Risk factors associated with low bone mineral density in children with idiopathic scoliosis: a scoping review

BACKGROUND

Children with idiopathic scoliosis (IS) have a high risk of osteoporosis and IS with low bone mineral density (BMD) are susceptible to curve progression. This review aims to explore the risk factors of low BMD in children with IS.

METHODS

Studies were retrieved from 5 databases that were published up to January 2022. Search terms are keywords in titles or abstracts, including subject headings related to "Scoliosis", "Bone Mineral Density", and "Risk Factors". Observational studies on risk factors of low BMD in children with IS were enrolled in this review. The number of studies, sample size, outcome measures, research type, endocrine, and lifestyle-related factors, gene/signal pathway, and other contents were extracted for qualitative analysis.

RESULTS

A total of 56 studies were included in this scoping review. Thirty studies involved genetic factors that may affect BMD, including the Vitamin-D receptor gene, RANK/RANKL signal pathway, the function of mesenchymal stem cells, Runx2, Interleukin-6 (IL-6), and miR-145/β-catenin pathway. Eight studies mentioned the influence of endocrine factors on BMD, and the results showed that serum levels of IL-6, leptin and its metabolites, and ghrelin in children with IS were different from the age-matched controls. In addition, there were 18 articles on lifestyle-related factors related to low BMD in children with IS, consisting of physical activity, calcium intake, Vitamin D level, and body composition.

CONCLUSIONS

Genetic, endocrine, and lifestyle-related factors might relate to low BMD and even osteoporosis in IS. To prevent osteoporosis, the effectiveness of regular screening for low BMD risk factors in children with IS needs to be investigated. Additionally, clear risk factors suggest strategies for bone intervention. Future studies should consider the effectiveness of calcium and vitamin D supplements and physical activity in BMD improvement.

Aphanius fasciatus: a molecular model of scoliosis?

STUDY DESIGN

Observational study of Killifish with spinal deformities OBJECTIVE: To evaluate the morphology and molecular biology of Aphanius fasciatus with severe spine deformities. Idiopathic Scoliosis affects 3% of the population and is an abnormal three-dimensional curvature of the spine with unknown cause. The lack of a model system with naturally occurring spinal curvatures has hindered research on the etiology of IS.

METHODS

The Mediterranean killifish Aphanius fasciatus, collected from the coast of Sfax (Tunisia), which has an inborn skeletal deformity was chosen. We used morphologic features to evaluate the severity of scoliosis according to the different types and performed a biochemical analysis using factors previously studied in humans (estradiol, melatonin and Insulin Growth Factor 1 "IGF-1").

RESULTS

We have detected relevant molecular deviations that occur in Killifish deformities and the fish with severe scoliosis are smaller and less old than the ones with milder scolioses. Furthermore, a significant change in levels of ovarian estradiol, liver IGF-1 and brain melatonin was noted between deformed and normal fish.

CONCLUSIONS

Aphanius fasciatus could be used as a molecular model system to study the etiology of IS in humans as the characterization of the Aphanius fasciatus scoliosis syndrome has revealed morphological and biochemical parallels to IS. However, it is important to note the limitations of the proposed model, including the short lifespan of the fish.

LEVEL OF EVIDENCE

III.

Body Composition in Japanese Girls with Adolescent Idiopathic Scoliosis

Introduction

There are few reports on body composition, particularly muscle mass, in patients with adolescent idiopathic scoliosis (AIS). The purpose of this study was to measure body composition including muscle mass and estimated bone mass of patients with AIS using bioelectrical impedance analysis (BIA) and to clarify the relationship between the degree of scoliosis and body composition.

Methods

The subjects were 210 girls (mean age 14.0 years, range 10-18 years) whose body composition was evaluated using BIA (Tanita MC-780). Body mass index (BMI), percent body fat (%BF), lean muscle mass index (LMI: muscle mass/height^2), and estimated bone mass index (eBoneMI: estimated bone mass/height^2) were determined by age and compared with those of previous reports. We divided 111 subjects whose bone maturation was complete into two groups for comparison of body composition metrics: those with Cobb angle <40° (moderate scoliosis group) and those with Cobb angle ≥40° (severe scoliosis group). The relationships between Cobb angle and each body composition parameter were evaluated.

Results

Age-adjusted BMI, %BF, and LMI tended to be low at all ages compared with means for the healthy Japanese population as previously reported. BMI, LMI, and eBoneMI were significantly lower in the severe scoliosis group compared with those in the moderate scoliosis group (p<0.05). In addition, all BMI, LMI, and eBoneMI were weakly correlated with Cobb angle (r= -0.20, -0.26, and -0.24).

Conclusions

On the basis of the results of this study, patients with AIS are thinner, with lower BMI, %BF, and LMI compared with healthy girls of the same age. Furthermore, factors such as lower BMI, lower muscle mass, and lower estimated bone mass were correlated with progressive scoliosis.

Physical Activities and Lifestyle Factors Related to Adolescent Idiopathic Scoliosis

BACKGROUND

In addition to genetic factors, environmental and lifestyle factors are thought to play an important role in the onset of adolescent idiopathic scoliosis (AIS). This cross-sectional study was conducted to explore lifestyle factors related to AIS.

METHODS

This study included 2,759 Japanese female junior high school students who planned a secondary screening after an initial moiré topography screening indicated possible scoliosis. The students and their mothers, or guardians, were asked to fill out a questionnaire consisting of 38 questions about demographic factors, lifestyle-related factors, social factors, household environment, participation in sports, health status, and factors related to the mother's pregnancy and delivery. The questionnaire was completed by 2,747 students (a 99.6% response rate). After excluding students with heart disease, neurological disease, or a congenital vertebral anomaly, 2,600 students were eligible for assessment. After undergoing a secondary screening with standing radiographs of the spine, students were assigned to the normal (control) group if radiographs showed a curve of <15° or to the scoliosis group if they had a curve of ≥15°. The odds ratios (ORs) for AIS in relation to the possible risk or preventive factors were estimated by logistic regression analyses.

RESULTS

No lifestyle-related factor was significantly associated with AIS. However, AIS was associated with classical ballet training (OR, 1.38; 95% confidence interval [CI], 1.09 to 1.75); the odds of AIS developing increased as the child's frequency of training, number of years of experience, and duration of training in ballet increased. The OR for AIS was 1.5 times higher for participants whose mothers had scoliosis. AIS was also associated with a low body mass index (BMI). These associations remained even after mutual adjustment was performed.

CONCLUSIONS

No association was found between AIS and lifestyle-related factors. However, classical ballet training, a family history of scoliosis, and low BMI may be associated with AIS.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Ultrastructure of Intervertebral Disc and Vertebra-Disc Junctions Zones as a Link in Etiopathogenesis of Idiopathic Scoliosis

Background Context. There is no general accepted theory on the etiology of idiopathic scoliosis (IS). An important role of the vertebrae endplate physes (VEPh) and intervertebral discs (IVD) in spinal curve progression is acknowledged, but ultrastructural mechanisms are not well understood. Purpose. To analyze the current literature on ultrastructural characteristics of VEPh and IVD in the context of IS etiology. Study Design/Setting. A literature review. Results. There is strong evidence for multifactorial etiology of IS. Early wedging of vertebra bodies is likely due to laterally directed appositional bone growth at the concave side, caused by a combination of increased cell proliferation at the vertebrae endplate and altered mechanical properties of the outer annulus fibrosus of the adjacent IVD. Genetic defects in bending proteins necessary for IVD lamellar organization underlie altered mechanical properties. Asymmetrical ligaments, muscular stretch, and spine instability may also play roles in curve formation. Conclusions. Development of a reliable, cost effective method for identifying patients at high risk for curve progression is needed and could lead to a paradigm shift in treatment options. Unnecessary anxiety, bracing, and radiation could potentially be minimized and high risk patient could receive surgery earlier, rendering better outcomes with fewer fused segments needed to mitigate curve progression.

Understanding the Basis of Genetic Studies: Adolescent Idiopathic Scoliosis as an Example

STUDY DESIGN

A review of the general concepts of genetics studies with specific reference to adolescent idiopathic scoliosis (AIS).

OBJECTIVES

To equip the average spine surgeon with the vocabulary and understanding needed to understand the genetics of scoliosis and the approaches used to identify risk genes.

SUMMARY OF BACKGROUND DATA

Adolescent idiopathic scoliosis is a multifactorial disease. Increasing evidence from families and monozygotic twins suggests the involvement of genetic factors. An estimation of heritability also indicates a strong influence of genetics on the disease. Increasing focus has been placed on identifying genes and genetic variants associated with AIS.

REVIEW

This is a review of genes and genetic variations, the phenotype definition of AIS in genetics studies, concepts and approaches to identifying associated genes, and the evaluation of results. Different types of genetic variations are present in the genome. These variations may modulate the expression or function of protein products, which in turn alter individuals' susceptibility to disease. Identifying the variants related to AIS requires an objective and clearly defined phenotype, among which the Cobb angle is commonly used. The phenotype helps classify subjects into cases and controls. By selecting candidate genes of growth factors and hormonal receptors, which are speculated to be involved in the mechanism of disease, the variants within these genes were compared between cases and controls to identify any differences. Another approach was to use large families and inspect the co-segregation of variants and phenotypes. Recently, arrays covering the variants of the whole genome were developed and assist in high-throughput screening for associated genes.

CONCLUSIONS

Genetic factors have an important role in AIS. Deciphering the genes and genetic variants associated with AIS can improve our understanding of the mechanisms of the disease, as well as assist in designing treatment methods and preventive measures.

The growth hormone receptor polymorphism in patients with acromegaly: relationship to BMI and glucose metabolism

The aim of this study was to investigate association between the frequencies of Growth Hormone receptor (d3GHR) gene polymorphisms and some clinical parameters of acromegalic patients. Total of 35 acromegalic patients were enrolled to study. The d3GHR polymorphism was identified by using polymerase chain reaction from peripheral blood samples. The levels of systolic and diastolic blood pressure, BMI, fasting plasma glucose (FPG), Fasting insulin, HOMA-IR, IGF-I, GH, IGFBP3, triglyceride, HDL and LDL cholesterol concentrations were evaluated. The frequencies of d3GHR genotypes were found as follows; 5 (14.3%) subjects had d3/d3, 11 (31.4%) had d3/fl and 19 (54.3%) had fl/fl in patients. The prevalence of the d3 and fl alleles was 30 and 70%, respectively. Systolic blood pressure, fasting insulin and HOMA-IR was found significantly increased in homozygote d3GHR genotype group compared to d3/fl subjects (P < 0.05). In addition, BMI was observed significantly different among three genotypes (P = 0.007) and in the subjects with d3/d3 genotype, BMI was found significantly higher than d3/fl and fl/fl genotypes groups. As well as, no significant difference was found between the d3 and fl alleles group in terms of the clinical parameters except for BMI (P = 0.002). It can be said that the d3GHR gene polymorphism may affect BMI, systolic blood pressure and insulin regulation. At the same time we can say homozygote d3GHR genotype and d3 allele carriers may have more risk than other genotypes for high BMI.

The genetic epidemiology of idiopathic scoliosis

Purpose

Idiopathic scoliosis is a complex developmental syndrome defined by an abnormal structural curvature of the spine. High treatment costs, chronic pain/discomfort, and the need for monitoring at-risk individuals contribute to the global healthcare burden of this musculoskeletal disease. Although many studies have endeavored to identify underlying genes, little progress has been made in understanding the etiopathogenesis. The objective of this comprehensive review was to summarize genetic associations/linkages with idiopathic scoliosis, as well as explore the strengths and weaknesses of each study, such that it may serve as a guide for the design and interpretation of future genetic studies in scoliosis.

Methods

We searched PubMed and Human Genome Epidemiology (HuGE) Navigator using the search terms “gene and scoliosis”. Linkage or association studies published in English and available full-text were further analyzed as regards results, experimental design, and statistical approach.

Results

We identified and analyzed 50 studies matching our criteria. These consisted of 34 candidate gene studies (6 linkage, 28 association) and 16 genome-wide studies [14 pedigree-based linkage, 2 genome-wide association studies (GWAS)]. Findings involved genes related to connective tissue structure, bone formation/metabolism, melatonin signaling pathways, puberty and growth, and axon guidance pathways. Variability in results between studies suggested ethnic and/or genetic heterogeneity.

Conclusions

The major difficulty in idiopathic scoliosis research is phenotypic and genetic heterogeneity. Genetic research was overrepresented by underpowered studies. The use of biological endophenotypes, as well as restricted clinical definitions, may help to partition variation and increase the power of studies to detect or confirm an effect.

SNP rs11190870 near LBX1 is associated with adolescent idiopathic scoliosis in southern Chinese

A study was conducted to validate the most significant single nucleotide polymorphism (SNP) from a genome-wide association study of Japanese adolescent idiopathic scoliosis (AIS) patients in an independent southern Chinese population. In total, 300 AIS patients fulfilled the clinical criteria and 788 controls with MRI scans of the spine were included in the replication study. We employed case-control analysis to study the association of SNP rs11190870 near LBX1 (ladybird homeobox 1) with AIS in a southern Chinese population. The results suggest that SNP rs11190870 is significantly associated with AIS (P=9.1 × 10(-10); odds ratio=1.85; 95% confidence interval=1.52-2.25). The results of this study confirm that SNP rs11190870 is associated with AIS.

Biochemistry of adolescent idiopathic scoliosis

This chapter reviews the biochemical, hormonal, and hematological factors in the onset and development of adolescent idiopathic scoliosis (AIS), an orthopedic entity of unknown etiology. Briefly, AIS is defined as a lateral curvature of the spine combined with vertebral rotation that occurs in patients of 10 years of age or older until bone maturity (18-20 years of age). AIS is predominant in females. If untreated, the curvature could evolve with negative long-term prognosis including psychosocial impact, back pain, pulmonary compromise, cor pulmonale, and even death due to respiratory failure. Causes of the disease have been postulated to involve genetics, abnormal muscle, connective tissue and bone structures, and neuroendocrine disorders. Psychological pathways have also been studied. Little data, however, have been collected on bone turnover in these patients. Some studies demonstrated decreased bone mineral density which may be suggestive of increased osteoblast activity. Other studies suggested a correlation to abnormal platelet morphology. Alterations in the spinal muscle contractile function may be responsible for spinal curvature. Measurement of trace elements in serum revealed impaired zinc and selenium metabolism, probably secondary to hormonal deregulation. Subsequent endocrine studies suggested a role for leptin and growth hormone in AIS. Recently, a neuroendocrine hypothesis has been proposed. This theory involves a unique melatonin-signaling dysfunction and opens new frontiers in the elucidation of the pathologic mechanisms for onset and progression of this disease.

The distribution of exon 3-deleted/full-length growth hormone receptor polymorphism in the Turkish population

OBJECTIVE

The exon 3-deleted/full-length (d3/fl) growth hormone receptor (d3/fl-GHR) polymorphism has been associated with responsiveness to GH therapy in some children and also with adult height variation in the general population. We aimed to evaluate the distribution of d3/fl-GHR polymorphism in a Turkish population.

METHODS

The study included 477 (54 females/423 males) healthy adults with a mean±SD age of 31.1±9.0 years (range: 18-57). Height and body mass index (BMI) were expressed as standard deviation score (SDS) according to national standards. All adults had normal height and BMI SDSs (between -2 and +2). GHR exon 3 isoforms were studied by simple multiplex polymerase chain reaction method. Insulin-like growth factor-1 (IGF-1) and IGF-binding protein-3 (IGFBP-3) values were also measured and expressed as SDS.

RESULTS

The distribution of the GHR exon 3 genotypes in the Turkish healthy adults was 35% (n=167) for fl/fl, 39% (n=186) for fl/d3, and 26% (n=124) for d3/d3. There was no difference between genders in GHR exon 3 genotypes. Frequencies of fl allele and d3 allele were 54.5% and 45.5%, respectively. There were no differences in height SDS and BMI SDS among the three d3/fl-GHR genotype groups. There was a significant difference in IGFBP-3 SDS between fl/fl and fl/d3 groups (p=0.022).

CONCLUSIONS

This study presents the results of GHR polymorphism in a Turkish population as a reference for further studies. The distribution was similiar to European populations. There were no correlations between GHR isoforms and height SDS or other clinical/biochemical characteristics of the individuals except for higher IGFBP-3 levels in the fl/d3 group as compared to the fl/fl group. Whether this finding implies an abnormality, needs further investigation.

The growth hormone receptor (GHR) exon 3 polymorphism and its correlation with metabolic profiles in obese Chinese children

OBJECTIVE

We investigated the correlation between the growth hormone receptor (GHR) exon 3 polymorphism and the metabolic profiles of Chinese children with obesity.

SUBJECTS AND METHODS

A total of 409 obese/overweight children and 206 normal weight children were recruited. Anthropological and biochemical indexes including insulin and lipid profiles were measured. Genomic DNA was extracted from the peripheral blood leukocytes, and the GHR exon 3 polymorphism was genotyped by polymerase chain reaction. Homeostasis model of assessment for insulin resistance index (HOMA-IR) and insulin sensitivity index (ISI) were calculated using the homeostasis model.

RESULTS

The frequency of the exon 3-deleted GHR (d3-GHR) polymorphism within the obese group was significantly higher than that of the control group (p < 0.05). Body mass index (BMI), fasting insulin (FIns), HOMA-IR, total cholesterol, and triglycerides were significantly lower in the d3-GHR (d3/d3 and d3/fl) group than in the full-length GHR (fl/fl, fl-GHR) group (p < 0.05). After adjustment for BMI, cholesterol level was still significantly lower and HOMA-IR was marginally lower (p = 0.079) in the d3-GHR obese group. There was no statistically significant difference in BMI, FIns, HOMA-IR, ISI, total cholesterol, or triglyceride levels between the two genotypes in the control group.

CONCLUSION

We report that the d3-GHR polymorphism has a significant effect on BMI and the metabolic parameters of Chinese children with obesity. The d3 allele may have a protective effect on the development of metabolic syndrome by increasing insulin sensitivity.

Lack of association between the promoter polymorphisms of MMP-3 and IL-6 genes and adolescent idiopathic scoliosis: a case-control study in a Chinese Han population

STUDY DESIGN

Case-control study.

OBJECTIVE

This study is to replicate the association between the promoter polymorphisms of matrix metalloproteinase (MMP)-3 (-1171 5A/6A rs3025058) and interleukin (IL)-6 genes (-174G/C rs1800795) and adolescent idiopathic scoliosis (AIS) in a Chinese Han population.

SUMMARY OF BACKGROUND DATA

Recently, promoter polymorphisms in MMP-3 and IL-6 have been reported to be associated with AIS. Such genetic association, if confirmed by replication in other samples, would point to a primary degenerative defect in the disc or nucleus pulposus and inflammation as the key pathogenic mechanisms of AIS.

METHODS

A total of 487 Chinese girls with AIS and 494 healthy age-matched adolescent girls were recruited consecutively during a 3-year period. The same genotyping technique as the original report was used to detect promoter polymorphisms of the MMP-3 and IL-6 genes. Statistical analysis of genotype frequencies between AIS patients and normal controls were performed by chi test.

RESULTS

In this association study of the MMP-3 polymorphism and the risk of scoliosis, no significant difference was found between cases and controls, both in term of allelic association (6A: 81.2% in cases vs. 81.8% in controls, 5A: 18.8% in cases vs. 18.2% in controls, P = 0.745) or genotype association (6A/6A: 65.9% in cases vs. 66.2% in controls, 5A/6A: 30.6% in cases vs. 31.2% in controls, and 5A/5A: 3.5% in cases vs. 2.6% in controls; P = 0.733). Among AIS patients, the maximal Cobb angles were also not different among MMP-3 genotypes (6A/6A: 31.1 degrees +/- 9.7 degrees, 5A/6A: 29.1 degrees +/- 10.5 degrees, and 5A/5A: 29.4 degrees +/- 11.2 degrees; P = 0.392). As for IL-6 polymorphism, -174G/C polymorphism was not found in the Chinese AIS patients, and all 100 AIS patients and 100 normal controls were found to carry the G/G wild type.

CONCLUSION

This study did not find any significant association of promoter polymorphisms of the MMP-3 (-1171 5A/6A rs3025058) and IL-6 gene (-174G/C rs1800795) with AIS. The results indicate that the MMP-3 promoter polymorphism is not associated with AIS in the Chinese population. Further studies, however, are needed to rule out the potential association with other promoter polymorphisms in IL-6.

Disproportionate body lengths correlate with idiopathic-type curvature in the curveback guppy

STUDY DESIGN

A comparative allometric study of body lengths in an animal model for human idiopathic-type scoliosis.

OBJECTIVE

To compare body length variation among adult curved and noncurved curveback female guppies.

SUMMARY OF BACKGROUND DATA

Tallness and/or abnormal anthropometric parameters have been correlated to idiopathic-type scoliosis (IS) in numerous studies. Heritable curvature in curveback has demonstrated morphologic and developmental similarities to human IS. Because control of body length in the guppy is heritable and variable, we investigated whether length might also be correlated to curvature in the curveback population.

METHODS

Component body lengths were measured from digital photographs for 321 (246 curved and 75 noncurved) females. Sources of experimental variation were omitted by only measuring 2-dimensional curves in mature females all from the same pedigree, and raised under controlled conditions of diet and environment. Body length was divided into 2 component parts (precaudal and caudal). Body lengths were tested statistically for correlation to curvature and curve magnitude.

RESULTS

Although absolute length does not correlate to curvature, this survey of length in the curveback model reveals 2 important similarities to anthropometric studies of IS: that there are disproportionate body lengths among females with curvature, and the suggestion of an underlying growth abnormality among curved individuals.

CONCLUSION

In order to better characterize the relationship between growth, length disproportion, and curvature in the guppy, further studies are warranted. However, this inquiry further supports the usefulness of curveback as a model for understanding the basic biology of idiopathic-type scoliosis and encourages study of growth-related factors.

Pathogenesis of adolescent idiopathic scoliosis in girls - a double neuro-osseous theory involving disharmony between two nervous systems, somatic and autonomic expressed in the spine and trunk: possible dependency on sympathetic nervous system and hormones with implications for medical therapy

Anthropometric data from three groups of adolescent girls - preoperative adolescent idiopathic scoliosis (AIS), screened for scoliosis and normals were analysed by comparing skeletal data between higher and lower body mass index subsets. Unexpected findings for each of skeletal maturation, asymmetries and overgrowth are not explained by prevailing theories of AIS pathogenesis. A speculative pathogenetic theory for girls is formulated after surveying evidence including: (1) the thoracospinal concept for right thoracic AIS in girls; (2) the new neuroskeletal biology relating the sympathetic nervous system to bone formation/resorption and bone growth; (3) white adipose tissue storing triglycerides and the adiposity hormone leptin which functions as satiety hormone and sentinel of energy balance to the hypothalamus for long-term adiposity; and (4) central leptin resistance in obesity and possibly in healthy females. The new theory states that AIS in girls results from developmental disharmony expressed in spine and trunk between autonomic and somatic nervous systems. The autonomic component of this double neuro-osseous theory for AIS pathogenesis in girls involves selectively increased sensitivity of the hypothalamus to circulating leptin (genetically-determined up-regulation possibly involving inhibitory or sensitizing intracellular molecules, such as SOC3, PTP-1B and SH2B1 respectively), with asymmetry as an adverse response (hormesis); this asymmetry is routed bilaterally via the sympathetic nervous system to the growing axial skeleton where it may initiate the scoliosis deformity (leptin-hypothalamic-sympathetic nervous system concept = LHS concept). In some younger preoperative AIS girls, the hypothalamic up-regulation to circulating leptin also involves the somatotropic (growth hormone/IGF) axis which exaggerates the sympathetically-induced asymmetric skeletal effects and contributes to curve progression, a concept with therapeutic implications. In the somatic nervous system, dysfunction of a postural mechanism involving the CNS body schema fails to control, or may induce, the spinal deformity of AIS in girls (escalator concept). Biomechanical factors affecting ribs and/or vertebrae and spinal cord during growth may localize AIS to the thoracic spine and contribute to sagittal spinal shape alterations. The developmental disharmony in spine and trunk is compounded by any osteopenia, biomechanical spinal growth modulation, disc degeneration and platelet calmodulin dysfunction. Methods for testing the theory are outlined. Implications are discussed for neuroendocrine dysfunctions, osteopontin, sympathoactivation, medical therapy, Rett and Prader-Willi syndromes, infantile idiopathic scoliosis, and human evolution. AIS pathogenesis in girls is predicated on two putative normal mechanisms involved in trunk growth, each acquired in evolution and unique to humans.

Adolescent idiopathic scoliosis and the single-nucleotide polymorphism of the growth hormone receptor and IGF-1 genes

The etiology of adolescent idiopathic scoliosis is undetermined despite years of research. A number of hypotheses have been postulated to explain its development, including growth abnormalities. The irregular expression of growth hormone and insulin-like growth factor-1 (IGF-1) may disturb hormone metabolism, result in a gross asymmetry, and promote the progress of adolescent idiopathic scoliosis. Initial association studies in complex diseases have demonstrated the power of candidate gene association. Prior to our study, 1 study in this field had a negative result. A replicable study is vital for reliability. To determine the relationship of growth hormone receptor and IGF-1 genes with adolescent idiopathic scoliosis, a population-based association study was performed. Single nucleotide polymorphisms with potential function were selected from candidate genes and a distribution analysis was performed. A conclusion was made confirming the insufficiency of an association between adolescent idiopathic scoliosis and the single-nucleotide polymorphism of the growth hormone receptor and IGF-1 genes in Han Chinese.

Clinical etiological classification of scoliosis: report of 1289 cases

OBJECTIVE

With the development of diagnostic techniques and in-depth understanding of lateral curvature of the spine (scoliosis), it is possible to differentiate idiopathic scoliosis from other forms with various known etiologies. The present study was to analyze data collected at the authors' center according to the current etiological spectrum and classification of scoliosis.

METHODS

One thousand, two hundred and eighty-nine consecutive patients with different forms of structural scoliosis were reviewed. The average age at first visit was 18 years, ranging from 4 months to 79 years. Corrective surgery was performed on patients aged from 9 to 28 years; their clinical data were retrieved for independent statistical analyses, and further compared with those obtained from the whole group.

RESULTS

The prevalence of non-idiopathic scoliosis was 25.3% in the whole series, but it increased to 34% in the surgical group aged from 9 to 28 years. Thirty-nine percent of patients with congenital scoliosis presented at least one developmental spinal cord malformation.

CONCLUSION

The current study has shown that the etiological distribution of scoliosis has changed a lot from what was true decades ago. Developmental malformation related to scoliosis is one of the risk factors for neurological complications during corrective surgery, so it is important to make an accurate diagnosis and take appropriate prophylactic measures to avoid relative neurological complications.

Common exon 3 polymorphism of the GH receptor (GHR) gene and effect of GH therapy on growth in Korean children with idiopathic short stature (ISS)

OBJECTIVE

A human GH receptor (GHR) gene exon 3 polymorphism (d3-GHR) has been reported to be associated with responsiveness to GH therapy. We assessed the frequencies of this polymorphism in Korean control and idiopathic short stature (ISS) populations, and analysed short-term growth response to GH therapy according to GHR-exon 3 genotypes in Korean children with ISS.

DESIGN AND PATIENTS

This was a retrospective study in 158 ISS children. Auxological and endocrine parameters were measured, and the GHR-exon 3 genotype was analysed. Allelic frequencies of GHR-exon 3 genotype were compared between the ISS group and a control group. GH had been administered for 62 patients, 52 of whom remained prepubertal after the first follow-up year. Changes in height velocity (HV) and IGF-1 and IGFBP-3 concentrations following GH therapy were compared in patients with these genotypes.

RESULTS

There was no difference in GHR-exon 3 genotype frequency between ISS and control groups of Koreans. However, the fl/fl genotype was more frequent in Koreans than in Caucasians. ISS children with d3-GHR showed a significantly higher increment in HV (P = 0.002) and a marginally significant increment in IGF-1 concentration (P = 0.064) at the first year of GH therapy.

CONCLUSION

fl-GHR was more frequently detected in a Korean population than in Caucasians. The growth promotion efficacy of GH therapy differed significantly between ISS patients with and without the d3-GHR allele. These findings indicate that the GHR-exon 3 polymorphism can affect the growth promoting efficacy of short-term GH therapy in Korean children with ISS.

Lack of association between the promoter polymorphism of the MTNR1A gene and adolescent idiopathic scoliosis

STUDY DESIGN

A genetic association study to investigate variation of the melatonin receptor 1A (MTNR1A) gene in adolescent idiopathic scoliosis (AIS) patients.

OBJECTIVE

To determine whether the MTNR1A gene promoter polymorphism is associated with the predisposition and/or disease severity of AIS.

SUMMARY OF BACKGROUND DATA

An involvement of the dysfunction of the melatonin pathway in the etiopathogenesis of AIS has been implicated in several studies. Recently, our group has found that the promoter polymorphism of the melatonin receptor 1B (MTNR1B) gene was associated with the occurrence of AIS. Hence, it is of interest to determine whether the promoter polymorphism of the MTNR1A gene could also associated with the occurrence or curve severity of AIS.

METHODS

A total of 226 AIS girls and 277 normal controls were recruited. SNP rs2119882 in the promoter region (-369 bp) of the MTNR1A gene was selected for the present study. Genotyping was performed by PCR-RFLP. Statistical analysis of genotype frequencies between case and control was performed by chi test. One-way ANOVA was used in comparison of mean maximum Cobb angles with different genotypes in case-only analysis.

RESULTS

Genotype and allele frequencies were comparable between case and control for SNP rs2119882 (P > 0.05). The mean maximum Cobb angles of different genotypes were similar with each other for SNP rs2119882.

CONCLUSIONS

Promoter polymorphism of the MTNR1A gene was not associated with the occurrence or curve severity of AIS. The MTNR1A gene may not be involved in the etiopathogenesis of AIS.