The significance of Pax2 expression in the ureter epithelium of children with vesicoureteric reflux

Genetic determinants of renal scarring in children with febrile UTI

BACKGROUND

Febrile urinary tract infections (UTIs) are among the most severe bacterial infections in infants, in which a subset of patients develops complications. Identifying infants at risk of recurrent infections or kidney damage based on clinical signs is challenging. Previous observations suggest that genetic factors influence UTI outcomes and could serve as predictors of disease severity. In this study, we conducted a nationwide survey of infant genotypes to develop a strategy for infection management based on individual genetic risk. Our aims were to identify genetic susceptibility variants for renal scarring (RS) and genetic host factors predisposing to dilating vesicoureteral reflux (VUR) and recurrent UTIs.

METHODS

To assess genetic susceptibility, we collected and analyzed DNA from blood using exome genotyping. Disease-associated genetic variants were identified through bioinformatics analysis, including allelic frequency tests and odds ratio calculations. Kidney involvement was defined using dimercaptosuccinic acid (DMSA) scintigraphy.

RESULTS

In this investigation, a cohort comprising 1087 infants presenting with their first episode of febrile UTI was included. Among this cohort, a subset of 137 infants who underwent DMSA scanning was subjected to gene association analysis. Remarkable genetic distinctions were observed between patients with RS and those exhibiting resolved kidney involvement. Notably, the genetic signature indicative of renal scarring prominently featured mitochondrial genes.

CONCLUSIONS

In this nationwide study of genetic susceptibility to RS after febrile UTIs in infancy, we identified a profile dominated by mitochondrial polymorphisms. This profile can serve as a predictor of future complications, including RS and recurrent UTIs.

Associations between neurofilament light-chain protein, brain structure, and chronic kidney disease

BACKGROUND

Neurofilament light-chain (NfL) protein is a blood-based marker of neuroaxonal injury. We sought to (1) compare plasma NfL levels in children with chronic kidney disease (CKD) and healthy peers, (2) characterize the relationship between NfL level and kidney function, and (3) evaluate NfL as a predictor of abnormal brain structure in CKD.

METHODS

Sixteen children with CKD due to congenital kidney anomalies and 23 typically developing peers were included. Plasma NfL was quantified using single-molecule array immunoassay. Participants underwent structural magnetic resonance imaging. Multiple linear regression models were used to evaluate the association between plasma NfL levels, kidney function, and brain structure.

RESULTS

An age × group interaction was identified whereby NfL levels increased with age in the CKD group only (estimate = 0.65; confidence interval (CI) = 0.08-1.22; p = 0.026). Decreased kidney function was associated with higher NfL levels (estimate = -0.10; CI = -0.16 to -0.04; p = 0.003). Lower cerebellar gray matter volume predicted increased plasma NfL levels (estimate = -0.00024; CI = -0.00039 to 0.00009; p = 0.004) within the CKD group.

CONCLUSIONS

Children with CKD show accelerated age-related increases in NfL levels. NfL level is associated with lower kidney function and abnormal brain structure in CKD.

IMPACT

NfL is a component of the neuronal cytoskeleton providing structural axonal support. Elevated NfL has been described in relation to gray and white matter brain volume loss. We have previously described the abnormal cerebellar gray matter in CKD. We explored the relationship between NfL, CKD, and brain volume. There is an accelerated, age-related increase in NfL level in CKD. Within the CKD sample, NfL level is associated with abnormal kidney function and brain structure. Decreased kidney function may be linked to abnormal neuronal integrity in pediatric CKD.

Molecular Screening of PAX2 Gene Polymorphism in Primary Vesicoureteral Reflux Patients in Taif Governorate, KSA

<b>Background and Objective:</b> Primary Nonsyndromic Vesicoureteral Reflux (PVUR) is a widespread genetic malformation and considered a prevalent Congenital Abnormality of the Kidney and Urinary Tract (CAKUT). Mutations in the <i>PAX2 </i>gene have been associated with abnormalities in the kidney extending from CAKUT to oncogenic processes. The present study analyzes the <i>PAX2</i> polymorphisms and their association with primary VUR in Saudi children patients from the Taif governorate. <b>Materials and Methods:</b> Fifteen children with primary VUR were identified and screened for gene mutations in the <i>PAX2</i> gene by direct sequencing method of purified Polymerase Chain Reaction (PCR) products of all exons to elucidate the correlation between <i>PAX2</i> gene and VUR. <b>Results:</b> Seven new variants have been defined. Three polymorphic missense variants in homozygous genotype form were found in intron 8 and detected in eight patients, One missense mutation was found in exon 10 in the site of transactivation domain and detected in ten patients and <i>in-silico</i> analysis predicted it as a pathogenic one, Three mutations were found in exon 11 and detected in all patients as a compound homozygous. <b>Conclusion:</b> <i>PAX2</i>is important for normal kidney development and mutations in the gene possibly lead to disturbance in the protein structure and could be non-functional thus mutations in <i>PAX2</i> may be one of the causes of PVUR in Saudi Arabia. Further investigation is necessary to understand the aetiology of disease and maybe other genes implicated in VUR.

Impact of next generation sequencing on our understanding of CAKUT

Congenital abnormalities of the kidney and urinary tract (CAKUT) form the leading cause of pediatric end-stage renal disease. Knowledge on the molecular mechanisms that underlie CAKUT leads to the improvement of DNA diagnostics and counseling regarding prognosis and recurrence risk estimation for CAKUT patients and their relatives. Implementation of next generation sequencing in research and diagnostic settings has led to the identification of the molecular basis of many developmental diseases. In this review, we summarize the efforts on next generation sequencing in CAKUT research and we discuss how next generation sequencing added to our understanding of CAKUT genetics. Although next generation sequencing has certainly proven to be a game changer in the field of disease gene identification and novel CAKUT-causing gene variants have been identified, most CAKUT cases still remain unsolved. Occurring with genetic and phenotypic heterogeneity along with incomplete penetrance, the identification of CAKUT etiology poses many challenges. We see great potential for combined -omics approaches that include next generation sequencing in the identification of CAKUT-specific biomarkers, which is necessary to optimize the care for CAKUT patients.