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.

Mammalian target of rapamycin inhibitors (mTOR-I) lacks nephrotoxicity, has antineoplastic effects, and reduces viral infections in kidney transplant recipients. Earlier studies reported a significant incidence of wound healing complications and lymphocele. This resulted in the uncomfortable willingness of transplant clinicians to use these agents in the immediate posttransplant period. As evidence and experience evolved over time, much useful information became available about the optimal use of these agents. Understandably, mTOR-I effects wound healing through their antiproliferative properties. However, there are a lot of other immunological and nonimmunological factors which can also contribute to wound healing complications. These risk factors include obesity, uremia, increasing age, diabetes, smoking, alcoholism, and protein-energy malnutrition. Except for age, the rest of all these risk factors are modifiable. At the same time, mycophenolic acid derivatives, steroids, and antithymocyte globulin (ATG) have also been implicated in wound healing complications. A lot has been learnt about the optimal dose of mTOR-I and their trough levels, its combinations with other immunosuppressive medications, and patients’ profile, enabling clinicians to use these agents appropriately for maximum benefits. Recent randomized control trials have further increased the confidence of clinicians to use these agents in immediate posttransplant periods.

Marchiafava-Bignami disease (MBD) is a rare fatal neurological disorder characterized by demyelination, primary degeneration, and necrosis of the corpus callosum. Although MBD is mostly associated with chronic alcohol consumption and malnutrition, it has been reported in non-alcoholic patients. Serotonin syndrome is a rare but potentially fatal side effect of antidepressants that results from overstimulation of both central and peripheral serotonergic receptors. In this report, we present a case with fatal serotonin syndrome happening in a non-alcoholic patient with the chronic form of MBD. To our knowledge, this case is the first report of fatal serotonin syndrome due to citalopram in an MBD patient. The present report may indicate that citalopram and other SSRIs should not be used in patients with MBD. Our case is also among few reported cases in the literature where no cause was identified in a patient with no previous history of alcohol intake.

Hyperkalemia is a frequent complication in patients with chronic kidney disease (CKD) or heart failure (HF) and associated with neuromuscular manifestations, changes in the electrocardiogram, and increased risk of mortality. While data on the prevalence and management of hyperkalemia in the gulf region are scarce, risk factors such as preference for potassium-rich foods (e.g., dates and dried fruits/vegetables), periods of intense fasting (e.g., Ramadan), and diabetes (an ancestor of CKD and HF) are common.Therefore, a panel of nephrologists and cardiologists from countries of the Gulf Cooperation Council (GCC) convened to collate and review available data on the prevalence, regional drivers, and current practice in the management of hyperkalemia in the region.Eventually, this review provides consensus recommendations on a balanced utilization of dietary and pharmacological options including new potassium binders for achieving and sustainably maintaining desirable serum potassium levels in countries of the GCC region. Alignment with regional habits and practice was a key aspect to facilitate the uptake of the recommendations into physicians' practice and patients' lives. K E Y W O R D Schronic kidney disease, heart failure, hyperkalemia, potassium binding INTRODUCTIONHyperkalemia is a frequent complication in chronic kidney disease (CKD) and heart failure (HF) patients, particularly those on reninangiotensin-aldosterone inhibitor (RAASi) therapy. 1,2 It is associ-All authors contributed equally to the preparation of this manuscript.