Exploring the association between specific genes and the onset of idiopathic scoliosis: a systematic review

Congenital kyphoscoliosis: Analysis of vertebral abnormalities using model animals (Review)

The normal structure of the spinal vertebrae is important for maintaining posture and the normal function of the thoracoabdominal organs and nervous system. Kyphoscoliosis occurs when the spinal vertebrae curve excessively beyond their physiological curvature to the back and side. Congenital kyphoscoliosis, a type of kyphoscoliosis, develops in the fetal period and is present in early childhood. However, neither the mechanism of pathogenesis nor the responsible gene has been identified. The lack of established animal models is a significant hurdle that limits the study of congenital kyphoscoliosis. Over the past 15 years, we have been accumulating data on this issue using rat models, based on the idea that the development of congenital kyphoscoliosis is caused by the abnormal expression of genes involved in normal bone formation. We hypothesize that analysis of an animal model of congenital kyphoscoliosis will provide a basis for the treatment of this disease in humans. The present review aimed to introduce molecules and mechanisms associated with the pathogenesis of kyphoscoliosis and to discuss the usefulness of studying this disease using model rats that develop kyphoscoliosis.

Ultrasonographic assessment of magnetic growing rods overestimates the lengthening of the thoracic spine compared to radiographs in early-onset scoliotic patients

PURPOSE

Magnetic growing rods (MGRs) are one of the most common procedures to treat early-onset scoliosis (EOS). Radiographic examinations (X-ray) or ultrasonographic (US) assessments are used to evaluate the lengthening of the rods. X-ray exposes patients to radiation, while the US has not been validated and may be affected by the radiologist's ability to assess elongation. The research question of the present study is to compare the difference between US and X-ray growth assessments in EOS patients treated with MGRs.

METHODS

The study enrolled 65 patients consecutively from July 2011 to July 2022. Noninvasive lengthening was performed every four months, and X-ray follow-up was performed at different intervals. An experienced radiologist assessed the mean US rod elongation per session. The mean elongation/session of T2-T12 and T2-S1 was calculated, and the results were compared using an independent t-test.

RESULTS

The mean age at operation was 8.8 ± 2 years, and the mean follow-up was four ± two years. The average rod elongation assessed by the US was 3.1 ± 0.1 mm. The average rod elongation evaluated by X-ray was 1.2 ± 2.9 mm (T2-T12) and 1.8 ± 1.9 mm (T2-S1). The difference between the values measured by US and X-ray was statistically significant in the T2-T12 group (p < 0.05) and not significant in the T2-S1 group (p = 0.34).

CONCLUSIONS

This is the most extensive single-center study comparing US and X-ray data for MGRs in EOS patients. US overestimates thoracic spine elongation compared to X-ray. US elongation analysis could be appropriate in long thoracolumbar curves.

Patients treated by magnetic growing rods for early-onset scoliosis reach the expected average growth

INTRODUCTION

Magnetic controlled growing rods (MCGRs) are one of the most common procedures to treat early-onset scoliosis (EOS). One of the major concerns is that patients treated with MGCR do not reach an adequate height with MGCR. The present study has one of the largest sample sizes of EOS patients treated by MGCR. This study aims to demonstrate the efficacy of the treatment with MGCR in EOS patients, comparing our results with the estimated growth.

METHODS

Patients were consecutively enrolled from July 2011 to July 2022. The same surgical equipe performed all the procedures. The mean length of the patients was assessed by X-ray (T2-T12 and T2-S1 distance) by a team of expert radiologists. The estimated growth by Dimeglio was compared with the mean elongation obtained by year.

RESULTS

65 patients were included. 16 patients underwent final surgery. In group 1, patients reached a growth of 3.6 ± 8.7 mm (T2-T12) and 9.6 ± 27.6 mm (T2-S1). In group 2, patients grew 5.4 ± 5.7 mm (T2-T12) and 9 ± 9 mm (T2-S1).81% of the estimated elongation during the treatment was obtained during the first surgery. The difference between Dimeglio's estimated growth and the value obtained by MGCR was -4.3 ± 8.7 mm(T2-T12) and -12.3 ± 12.2 mm (T2-S1) in group 1 (p < 0.001) and -1.1 ± 4.2 mm (T2-T12) and -6.6 ± 6.0 mm (T2-S1) in group 2 (p = 0.001).

CONCLUSIONS

MGCR patients reached and overlapped the growth target according to the score by Dimeglio. However, the value of growth tended to reduce over the years. Lastly, obtaining the most significant elongation possible at the first surgery is mandatory, comprising 81% of the total value.

Are the Spinal Changes in the Course of Scoliogeny Primary but Secondary?

In this opinion article, there is an analysis and discussion regarding the effects of growth on the spinal and rib cage deformities, the role of the rib cage in scoliogeny, the lateral spinal profile in adolescent idiopathic scoliosis (AIS), the genetics and epigenetics of AIS, and the interesting and novel field investigating the sleep impact at nighttime on AIS in relation to the sequence of the scoliogenetic changes in scoliotics. The expressed opinions are mainly based on the published peer-reviewed research of the author and his team of co-authors. Based on the analysis noted above, it can be postulated that the vertebral growth changes in the spine during initial idiopathic scoliosis (IS) development are not primary-intrinsic but secondary changes. The primary cause starting the deformity is not located within the vertebral bodies. Instead, the deformations seen in the vertebral bodies are the secondary effects of asymmetrical loads exerted upon them, due to muscular loads, growth, and gravity.

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.

The Whole-Exome Sequencing of a Cohort of 19 Families with Adolescent Idiopathic Scoliosis (AIS): Candidate Pathways

A significant genetic involvement has been known for decades to exist in adolescent idiopathic scoliosis (AIS), a spine deformity affecting 1-3% of the world population. However, though biomechanical and endocrinological theories have emerged, no clear pathophysiological explanation has been found. Data from the whole-exome sequencing performed on 113 individuals in 19 multi-generational families with AIS have been filtered and analyzed via interaction pathways and functional category analysis (Varaft, Bingo and Panther). The subsequent list of 2566 variants has been compared to the variants already described in the literature, with an 18% match rate. The familial analysis in two families reveals mutations in the BICD2 gene, supporting the involvement of the muscular system in AIS etiology. The cellular component analysis revealed significant enrichment in myosin-related and neuronal activity-related categories. All together, these results reinforce the suspected role of the neuronal and muscular systems, highlighting the calmodulin pathway and suggesting a role of DNA-binding activities in AIS physiopathology.

Sex differences in musculoskeletal injury and disease risks across the lifespan: Are there unique subsets of females at higher risk than males for these conditions at distinct stages of the life cycle?

Sex differences have been reported for diseases of the musculoskeletal system (MSK) as well as the risk for injuries to tissues of the MSK system. For females, some of these occur prior to the onset of puberty, following the onset of puberty, and following the onset of menopause. Therefore, they can occur across the lifespan. While some conditions are related to immune dysfunction, others are associated with specific tissues of the MSK more directly. Based on this life spectrum of sex differences in both risk for injury and onset of diseases, a role for sex hormones in the initiation and progression of this risk is somewhat variable. Sex hormone receptor expression and functioning can also vary with life events such as the menstrual cycle in females, with different tissues being affected. Furthermore, some sex hormone receptors can affect gene expression independent of sex hormones and some transitional events such as puberty are accompanied by epigenetic alterations that can further lead to sex differences in MSK gene regulation. Some of the sex differences in injury risk and the post-menopausal disease risk may be "imprinted" in the genomes of females and males during development and sex hormones and their consequences only modulators of such risks later in life as the sex hormone milieu changes. The purpose of this review is to discuss some of the relevant conditions associated with sex differences in risks for loss of MSK tissue integrity across the lifespan, and further discuss several of the implications of their variable relationship with sex hormones, their receptors and life events.

Association of LBX1 Gene Methylation Level with Disease Severity in Patients with Idiopathic Scoliosis: Study on Deep Paravertebral Muscles

Idiopathic scoliosis (IS) is a multifactorial disease with a genetic background. The association of Ladybird Homeobox 1 (LBX1) polymorphisms with IS has been proven in multiple studies. However, the epigenetic mechanisms have not been evaluated. This study aimed to evaluate the LBX1 methylation level in deep paravertebral muscles in order to analyze its association with IS occurrence and/or IS severity. Fifty-seven IS patients and twenty non-IS patients were examined for the paravertebral muscles’ methylation level of the LBX1 promoter region. There was no significant difference in methylation level within paravertebral muscles between patients vs. controls, except for one CpG site. The comparison of the paravertebral muscles’ LBX1 promoter region methylation level between patients with a major curve angle of ≤70° vs. >70° revealed significantly higher methylation levels in 17 of 23 analyzed CpG sequences at the convex side of the curvature in patients with a major curve angle of >70° for the reverse strand promoter region. The association between LBX1 promoter methylation and IS severity was demonstrated. In patients with severe IS, the deep paravertebral muscles show an asymmetric LBX1 promoter region methylation level, higher at the convex scoliosis side, which reveals the role of locally acting factors in IS progression.