Characterization of NPHS2 gene polymorphisms associated to steroid resistance nephrotic syndrome in Indian children

Analysis of the association of NPHS2 and ACTN4 genes polymorphism with nephrotic syndrome in Egyptian children

BACKGROUND

One of the most common kidney illnesses in developing countries is pediatric nephrotic syndrome (PNS), which is frequently associated with dyslipidemia and edema. The rapid discovery of genes related to NS has aided in the understanding of the molecular mechanics of glomerular filtration. The goal of this study is to determine the relationship between NPHS2 and ACTN4 in PNS youngsters.

METHODS

A study with 100 NS children and 100 healthy matched volunteers was conducted. Genomic DNA was extracted from peripheral blood. Single-nucleotide polymorphisms were genotyped using ARMS-PCR.

RESULTS

A substantial decline in the level of albumin was found in NS cases (P < 0.001) Further on, a significantly difference in T.C and TG level between healthy and NS patient. Molecular study showed a highly significant difference of NS patients from controls regarding NPHS2 rs3829795 polymorphic genotypes as the GA heterozygous genotype shows highly significant difference from controls (P < 0.001) as well as GA + AA genotypes (P < 0.001) in comparison with GG genotype. Regarding rs2274625, The GA heterozygous genotype showed no statistically significant difference between genotypes and alleles with NS (P = 0.246). Association of AG haplotype NPHS2 rs3829795-rs2274625 haplotypes found a significant association with the risk of developing NS (P = 0.008). Concerning the ACTN4 rs121908415 SNP, there was no link between this mutation and NS children.

CONCLUSION

The correlation of AG haplotype NPHS2 rs3829795-rs2274625 haplotypes identified a strong association with the likelihood of getting NS, according to our findings. There was no connection found between the ACTN4 rs121908415 SNP and NS children.

NPHS2 gene mutations in azerbaijani children with steroid-resistant nephrotic syndrome

Nephrotic syndrome (NS) is characterized by proteinuria in children. Steroid- resistant NS (SRNS) is defined by resistance to standard steroid therapy, and it continues to be one of the most common causes of chronic renal failure. Molecular studies have revealed specialized molecules in different regions of the podocytes that play a role in proteinuria. Mutations in NPHS2 that encode for podocin constitute a frequent cause of SRNS worldwide. This study aimed to screen for podocin mutations in Azerbaijani patients with SRNS. Our study included 21 pediatric patients with SRNS aged between 0 and 18 years and the same number of healthy control groups. Mutational analysis of the NPHS2 gene was performed using direct sequencing methods. Disease-causing mutations in the NPHS2 gene were detected in eight patients (38%). Thirteen patients (62%) had NPHS2 mutations without causing the disease. Two patients had p.Val290Met homozygous mutation; two had p.Arg229Gln homozygous mutations; and one each had p.Pro20Leu homozygote, p.Leu169Pro homozygote, p.Arg138Gln homozygote, and p.Arg168His homozygous mutations. When we correlated the NPHS2 mutation status with disease progression, there was a statistically significant increase in serum creatinine, proteinuria, and serum albumin values in patients with NPHS2 gene mutations compared to the group without mutation (P <0.05). Our study concludes that mutations of the NPHS2 gene (38%) are heterogeneous in Azerbaijani SRNS patients. Based on our results, we support a model in which ethnicity plays an important role in certain NPHS2 mutations. NPHS2 mutation analysis may help to better predict the course of the disease, remove unnecessary long-term immunosuppressive therapy, and develop specific treatment.

Analysis of NPHS2 Gene Mutations in Egyptian Children with Nephrotic Syndrome

BACKGROUND:

Mutations in the NPHS2 genes are the main aetiology of early-onset and familial steroid-resistant nephrotic syndrome (SRNS). The pathogenic NPHS2 mutation together with the p.R229Q variant has been less described among Egyptian children.

AIM:

This study aims to determine the mutation of NPHS2 in children with NS and discover the role of p.R229Q variant in SRNS

METHODS:

The study included 53 children with NS, and 53 healthy volunteers matched in age and sex controls. The median age at disease onset was 7.3 years. Among NS cases, 31 cases had steroid-sensitive nephrotic syndrome (SSNS) and 22 children with steroid-resistant nephrotic syndrome (SRNS). Polymerase chain reaction amplification of the whole coding region of NPHS2 gene was carried out for its mutational analysis. Restriction digestion testing was carried out after PCR to determine the presence of R229Q polymorphism. Randomly selected samples were re-genotyped by two independent technicians for assessment of Quality control

RESULTS:

NS patients showed a significant higher frequency of heterozygous genotype GA (89.5%) compared to control group (10.5%) with increased risk of NS (OR, 12.04; 95% CI, 2.61 to55.38; p < 0.0001). Moreover, SRNS showed a significant higher frequency of GA genotype (68.2%) than the SSNS group (6.5%). The GA genotype was associated with increased risk of SRNS (OR, 31.1; 95% CI, 5.73 to 168.48; P < 0.001) and the A allele was associated with increased risk of SRNS (OR, 15.52; 95% CI, 3.325 to 72.422; P < .001).

CONCLUSION:

R229Q polymorphisms are associated with SRNS, and any child with SRNS should be searched for mutations in the NPHS2 gene.

Evaluating the effect of BDNF Val66Met polymorphism on complex formation with HAP1 and Sortilin1 via structural modeling

Brain derived neurotrophic factor (BDNF) has a critical role in the neurogenesis, differentiation, survival of the neurons, regulation of the appetite, and energy homeostasis. Two key proteins, Huntingtin associated protein-1 (HAP1) and sortilin1, regulate the intracellular trafficking and stabilization of the precursor proBDNF through interaction with its prodomain region and mark it for secretion. Evidence suggests that the most frequent single nucleotide polymorphism (SNP) of BDNF gene (rs6265) has been associated with different psychiatric, neurodegenerative and eating disorders. In this study, structural bioinformatics and molecular dynamics (MD) simulations were applied, in order to get precise insights into the impact of Val66Met polymorphism on the proBDNF structure and its interaction with HAP1 and Sortilin1. Homology modeling, structure validation, refinement and also protein-protein docking were performed using appropriate servers. The stability, the fluctuations and the compactness of protein complexes were measured by MD simulation parameters including root mean square deviation (RMSD), root mean square fluctuation (RMSF) and Radius of gyration (Rg), respectively. The mutant proBDNF complexes with HAP1 and Sortilin1 revealed higher RMSD and RMSF values and also variable R_g over time compared with wild-type proBDNF. These computational results indicated that, wild-type proBDNF possessed more stable structure in binding with HAP1 and Sortilin1 compared with its mutant form. Therefore, Val66Met SNP could be deleterious due to making structural changes. It may cause a decrease in proBDNF secretion, which could possibly lead to different psychiatric, neurodegenerative and eating disorders. Further experimental lab studies are required for a more accurate conclusion.