PAX2 variant associated with bilateral kidney agenesis and broad intrafamilial disease variability

PAX2 Gene Mutation in Pediatric Renal Disorders-A Narrative Review

The PAX2 gene is a transcription factor that is essential for the development of the urinary system among other transcription factors. The role of PAX2 is highlighted from the seventh week of gestation, when it is involved in development processes and the emergence of nephrons and collecting tubes. Being an important factor in renal development, mutations of this gene can produce severe alterations in the development of the urinary tract, namely congenital anomalies of the kidneys and urinary tract. The first reported cases described with the PAX2 mutation included both renal anomalies and the involvement of other organs, such as the eyes, producing renal coloboma syndrome. Over the years, numerous cases have been reported, including those with only renal and urinary tract anomalies. The aim of this review is to present a summary of pediatric patients described to have mutations in the PAX2 gene to contribute to a better understanding of the genetic mechanism causing anomalies of the kidneys and urinary tract. In this review, we have included only pediatric cases with renal and urinary tract disorders, without the involvement of other organs. From what we know so far from the literature, this is the first review gathering pediatric patients presenting the PAX2 mutation who have been diagnosed exclusively with renal and urinary tract disorders.

Decreased Microglia in Pax2 Mutant Mice Leads to Impaired Learning and Memory

Impaired learning and memory ability is one of the characteristics of a variety of neurological diseases, and its molecular mechanisms are complex and diverse and are regulated by a variety of factors. It is generally believed that synaptic plasticity plays an important role in the process of learning and memory. The protein encoded by the Pax2 gene is a transcription factor involved in neuron migration and cell fate determination during neural development. Mice knocked out of BDNF in the Pax2 lineage-derived interneuron precursor exhibited learning disabilities and severe cognitive impairment. In this study, Pax2 heterozygous gene (Pax2^+/- mice) deletion mice were used as the research objects and behavioral tests were used to observe the effect of Pax2 gene deletion on learning and memory ability; morphological and molecular biological methods were used to observe the effect of Pax2 gene deletion on the neural structure. Single-cell transcriptome sequencing was used to observe the cell subtypes and differentially expressed genes (DEGs) and signaling pathways affected by Pax2 gene deletion and the possible molecular mechanisms. The results showed that Pax2^+/- mice had impaired learning and memory ability, abnormal synaptic structure, and significantly reduced number of microglia clusters, and DEGs were associated with pro-inflammatory chemokines. Finally, we speculate that Pax2 gene deletion may lead to abnormal chemokines and chemokine receptors by affecting microglia.

Autosomal dominant tubulointerstitial kidney disease: more than just HNF1β

Autosomal dominant tubulointerstitial kidney disease (ADTKD) refers to a group of disorders with a bland urinary sediment, slowly progressive chronic kidney disease (CKD), and autosomal dominant inheritance. Due to advances in genetic diagnosis, ADTKD is becoming increasingly recognized as a cause of CKD in both children and adults. ADTKD-REN presents in childhood with mild hypotension, CKD, hyperkalemia, acidosis, and anemia. ADTKD-UMOD is associated with gout and CKD that may present in adolescence and slowly progresses to kidney failure. HNF1β mutations often present in childhood with anatomic abnormalities such as multicystic or dysplastic kidneys, as well as CKD and a number of other extra-kidney manifestations. ADTKD-MUC1 is less common in childhood, and progressive CKD is its sole clinical manifestation, usually beginning in the late teenage years. This review describes the pathophysiology, genetics, clinical characteristics, diagnosis, and treatment of the different forms of ADTKD, with an emphasis on diagnosis. We also present data on kidney function in children with ADTKD from the Wake Forest Rare Inherited Kidney Disease Registry.

The term CAKUT has outlived its usefulness: the case for the defense

Congenital anomalies of the kidney and urinary tract form a spectrum of congenital structural disorders that are generally known under the term CAKUT. The term CAKUT was introduced 20 years ago and has been used extensively in literature since. Prof. Woolf has made a plea for abandoning this term in his "case for the prosecution." Here, I advocate for the continued use of CAKUT as an umbrella term for these related congenital kidney and urinary tract abnormalities. I explain why the term CAKUT accurately and usefully defines this group of related structural disorders with prenatal origin and why it makes sense to continue grouping these disorders given accumulating evidence for shared etiology of CAKUT phenotypes and the importance of grouping CAKUT phenotypes in genetic counseling.