SHOX Variations in Idiopathic Short Stature in North India and a Review of Cases from Asian Countries

Objective: Short stature homeobox (SHOX) haploinsufficiency underlies idiopathic short stature (ISS) and Leri-Weill dyschondrosteosis. The worldwide prevalence of SHOX variations in ISS varies from 2.5% to 15.0%. The aim of this study was to assess the implication of SHOX variation in ISS in North Indians and compare this with other cases of SHOX variations from Asian population. Methods: SHOX gene analysis was carried out by multiplex ligation-dependent probe amplification followed by Sanger sequencing in 54 patients with variable phenotypes. Comparison with other reports in a meta-analysis comprising the current study and 11 previous studies (n=979) was performed. Results: SHOX analysis resulted in 12.9% positivity (7.4% deletions and 5.5% duplications). SHOX association was seen significantly related to gender, with predominance in females (p=0.047). Short arms and forearms were the only significantly associated trait seen in 51.9% of children. The overall prevalence of SHOX variation was 15.2% in Asians with ISS. No significant difference was found in geographical region-specific analysis. Conclusion: This study summarises findings from the last decade and provides an updated picture of the prevalence of SHOX variations in Asians, emphasizing their potential as therapeutic targets in ISS patients. Further high quality, large investigations including functional validation is warranted to validate this association.

Estrogen Receptor 1 Gene Polymorphism and its Association with Idiopathic Short Stature in a North Indian Population

Objective: In the hypothalamic-pituitary-gonadotrophin axis, estrogen plays a key role in the regulation of bone maturation and growth plate closure. This study was designed to explore the link between single nucleotide polymorphisms (SNPs) in the estrogen receptor 1 (ESR1) gene with idiopathic short stature (ISS) susceptibility in a North Indian population. Methods: Four SNPs of ESR1 (rs543650, rs6557177, rs2234693 and rs9340799) were genotyped by Sanger sequencing in ISS patients and controls. Linkage disequilibrium (LD) and haplotyping were done by SNPStat and SHEsisPlus software. The extent of LD was determined by calculating D' and R2 values in SNP paired combinations. Results: Fifty-two ISS patients were compared with 68 controls. A significant positive association was found between rs6557177 and rs543650 genotype and ISS susceptibility. The frequencies of the rs6557177 CC genotype [p=0.030; odds ratio (OR)=0.13; 95% confidence interval (CI): 0.01-1.10] and rs543650 genotype TT (p=0.043; OR=0.29; 95% CI: 0.09-0.92) were increased in the ISS group compared with controls. However, no significant correlation was observed between clinical parameters of patients and these SNPs. rs543650 showed strong LD with rs2234693 and rs9340799, similarly rs2234693 and rs9340799. Conclusion: Our study showed that the CC genotype at rs6557177 and TT genotype at rs543650 of ESR1 constituted a risk factor for developing ISS in North Indian children. These findings may lead to a better understanding of the SNPs associated with ISS susceptibility.

Molecular cloning and expression profile of snow trout GPDH gene in response to abiotic stress.

Glycerol-3-phosphate dehydrogenase (GPDH) gene possibly plays a key role for cold acclimation process in snow trout during winter months when water temperature goes down to 4-5 °C. In this study, 1,012 bp nucleotide fragment of GPDH gene was obtained from two snow trout species (Schizothorax richardsonii and S. niger; family: Cyprinidae), distributed in several Himalayan rivers. The gene encoded a protein of 334 amino acids. The encoded protein sequence was very similar to GPDH of Danio rerio (94.36 %) using BLASTx searches. In S. richardsonii the qRT-PCR showed highest expression in muscle tissue followed by liver and also revealed 19 fold gene expression in liver tissue under cold (5 °C) in comparison with warm (15 °C) condition. The elevated expression levels of GPDH cDNA on cold treatment furthermore suggest that GPDH plays a role in stress related responses in S. richardsonii. The phylogenetic analysis showed that the two snow trout species GPDH share the same clade with characterized GPDHs from other teleost fishes suggesting a common evolutionary origin and a similar catalytic function. In addition, the Ka/Ks ratios of these sequences suggested that they are under purifying selection. Moreover, the expression profile of GPDH gene among co generic species of genus Schizothorax showed that GPDH cDNA expression was highest in S. richardsonii and lowest in S. esocinus which gives an indication of species specific adaptation in relation to different geographical areas.

Mutations of PHOX2B Gene in Patients of Obesity Hypoventilation Syndrome in Central India.

Background Paired-like homeobox 2B (PHOX2B) gene on chromosome 4p12 codes for a transcription factor having a role in the formation of noradrenergic neuronal circuits. Its mutations have been linked to congenital central hypoventilation syndrome (CCHS). The clinical presentation of both, obesity hypoventilation syndrome (OHS) and CCHS in adults (named late-onset central hypoventilation syndrome), is quite similar. Because of this symptomatic similarity, multifactorial causation of OHS, the mutation of PHOX2B gene was studied in patients with OHS in this study. Methods A hospital-based cross-sectional study was performed on patients diagnosed with OHS. The deoxyribonucleic acid was extracted from 2 mL of venous blood and was further amplified, specific to exon 3. The amplified products were cast and run in 2% agarose gel and then subjected to Sanger sequencing. Results Thirty patients of OHS (21 male; 9 female) were enrolled in the present study, average age being 51.7 years. The Sanger sequencing of the samples revealed no apparent areas of deletions and no apparent mutations. Conclusion Primers for exon 3 were used for amplification in thermocycler, as exon 3 is the most frequently mutated exon for PHOX2B gene, as per existing literature. The entire gene needs to be studied for mutations and the sample size needs to be increased.

Morphologic Features of the Distal Femur and Proximal Tibia: A Cross-Sectional Study.

Background The asymmetric medial and lateral condyles of the distal femur and proximal tibia have a direct influence on the biomechanics of knee joint and prostheses design. This study aimed to determine the morphologic data, that is., anteroposterior (AP) and mediolateral (ML) widths, and the radius of curvature (ROC) of the geometric arcs of the distal femur and proximal tibia. Methods One hundred and seventeen adult dry bones (57 femurs and 60 tibias) were studied. Aspect ratios (AP/ML) were calculated. The AP and ML widths were measured using digital Vernier Caliper with a measuring range of 0-150 mm, resolution of 0.01 mm, and accuracy ± 0.02 mm. The geometric arcs of femoral and tibial condyles were divided into three parts namely anterior 1/3rd, distal (femur) or middle (tibia) 1/3rd and posterior 1/3rd and were estimated in the sagittal plane for the femur and transverse plane for tibia using the ROC gauges. Results For the femur, the mean AP length for medial and lateral condyles was 55.62 mm and 57.93 mm, respectively, while the mean ML width was 73.45 mm. For the tibia, the mean AP length for medial condyle (MC) and lateral condyle (LC) was 47.74 mm and 43.46 mm, respectively. The mean aspect ratios for the distal femur and proximal tibia were 1.26 and 1.45, respectively. The mean aspect ratios for MC and LC of the femur were 0.50 and 0.52, respectively, whereas, for tibia, they were 0.61 and 0.71, respectively. The mean ROC for femoral MC - 20.77 mm, 31.42 mm, and 19.68 mm and for LC - 21.48 mm, 64.40 mm and 19.06 mm for the anterior, distal and posterior arcs, respectively. The mean ROC for tibial MC - 22.42 mm, 22.49 mm and 19.94 mm, and LC - 19.92 mm, 21.79 mm and 20.95 mm for the anterior, middle and posterior arcs, respectively. Conclusions The morphologic data accumulated in this study for both the distal femur as well as the proximal tibia would provide guidelines and help the manufacturers of joint prostheses to address the potential for compromised implant fit and re-design and make available 'anatomic' knee prostheses appropriate for the local population which would not only improve function but also prolong the longevity of the prostheses.