Identification and Characterization of Novel Mutations in Chronic Kidney Disease (CKD) and Autosomal Dominant Polycystic Kidney Disease (ADPKD) in Saudi Subjects by Whole-Exome Sequencing

Abstract

Background: Autosomal dominant polycystic kidney disease (ADPKD) is a condition usually caused by a single gene mutation and manifested by both renal and extrarenal features, eventually leading to end-stage renal disease (ESRD) by the median age of 60 years worldwide. Approximately 89% of ADPKD patients had either PKD1 or PKD2 gene mutations. The majority (85%) of the mutations are in the PKD1 gene, especially in the context of family history. Objectives: This study investigated the genetic basis and the undiscovered genes that are involved in ADPKD development among the Saudi population. Materials and Methods: In this study, 11 patients with chronic kidney disease were enrolled. The diagnosis of ADPKD was based on history and diagnostic images: CT images include enlargement of renal outlines, renal echogenicity, and presence of multiple renal cysts with dilated collecting ducts, loss of corticomedullary differentiation, and changes in GFR and serum creatinine levels. Next-generation whole-exome sequencing was conducted using the Ion Torrent PGM platform. Results: Of the 11 Saudi patients diagnosed with chronic kidney disease (CKD) and ADPKD, the most common heterozygote nonsynonymous variant in the PKD1 gene was exon15: (c.4264G > A). Two missense mutations were identified with a PKD1 (c.1758A > C and c.9774T > G), and one patient had a PKD2 mutation (c.1445T > G). Three detected variants were novel, identified at PKD1 (c.1758A > C), PKD2L2 (c.1364A > T), and TSC2 (deletion of a’a at the 3’UTR, R1680C) genes. Other variants in PKD1L1 (c.3813_381 4delinsTG) and PKD1L2 (c.404C > T) were also detected. The median age of end-stage renal disease for ADPK patients in Saudi Arabia was 30 years. Conclusion: This study reported a common variant in the PKD1 gene in Saudi patients with typical ADPKD. We also reported (to our knowledge) for the first time two novel missense variants in PKD1 and PKD2L2 genes and one indel mutation at the 3’UTR of the TSC2 gene. This study establishes that the reported mutations in the affected genes resulted in ADPKD development in the Saudi population by a median age of 30. Nevertheless, future protein–protein interaction studies to investigate the influence of these mutations on PKD1 and PKD2 functions are required. Furthermore, large-scale population-based studies to verify these findings are recommended.

In Silico Evaluation of the Potential Association of the Pathogenic Mutations of Alpha Synuclein Protein with Induction of Synucleinopathies

“…Nucleotide variations influence the physiological processes and contributing to various pathological conditions [ 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 ]. The pathogenic mutations can adversely affect protein function, protein-protein interactions (PPI), charge or spatial structure [ 49 , 50 ].…”

A Current Landscape on Alport Syndrome Cases: Characterization, Therapy and Management Perspectives

“…In the US, patients with various mutation types have significantly variable starting ages for ESRD. The following are the median (and 95% CIs) times from birth to end-stage renal disease: missense, 37 years (34)(35)(36)(37)(38)(39)(40); splice site, 28 years (26)(27)(28)(29)(30)(31)(32); truncating, 25 years (21-31); major deletion, 22 years (16-23); and small deletion, 22 years (19-27); P 0.0001 [13].…”

“…Recently, the 100,000 Genomes Project's 39,421 participants were tested for the bioinformatically predicted harmful missense mutations and 5.6% of them had a history of hematuria [36]. In Saudi Arabia, due to the high consanguinity rate (58%), several recessive mutations were reported [37][38][39][40].…”

Relationship between kidney ultrasound data and blood creatinine and urea levels in cats with autosomal dominant polycystic kidney disease

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