Performance of the ACMG-AMP criteria in a large familial renal glucosuria cohort with identified SLC5A2 sequence variants.

Familial Renal Glucosuria (FRG) is a co-dominantly inherited trait characterized by orthoglycaemic glucosuria. From 2003 to 2015 we have reported several cohorts validating SLC5A2 (16p11.2), encoding SGLT2 (Na+/glucose cotransporter family member 2), as the gene responsible for FRG. The aim of this work was to validate the variants identified in our extended FRG cohort of published, as well more recent unreported cases, according to the ACMG-AMP 2015 criteria. Forty-six variants were evaluated, including 16 novel alleles first described in this study. All are rare, ultra-rare or absent from population databases and most are missense changes. According to the ACMG-AMP standards, only 74% of the variants were classified as P/LP. The lack of descriptions of unrelated patients with similar variants or failing to test additional affected family members, averted a conclusion for pathogenicity in the alleles that scored VUS, highlighting the importance of both family testing and variant reporting. Finally, the cryo-EM structure of the hSGLT2-MAP17 complex in the empagliflozin-bound state improved the ACMG-AMP pathogenicity score by identifying critical/functional protein domains.

The Complexity of Decisions in Genetics: Annotation of Three Novel Variants in the PKD1 and PKD2 Genes.

As nephrology practice is evolving toward precision medicine, and genetic tests are becoming widely available, basic genetic literacy is increasingly required for clinical nephrologists. Yet, decisions based on results of genetic tests are seldom straightforward. We report a 37-year-old woman with autosomal dominant polycystic kidney disease (ADPKD) who was referred for medically assisted reproduction with monogenic preimplantation genetic testing (PGT-M). The PKD1 and PKD2 genes were screened for pathogenic variants. Sequencing analysis revealed the presence of three novel missense single nucleotide variants, two in the PKD1 gene - c.349T>G, p.(Leu117Val) and c.1736C>T, p.(Pro579Leu); and the third in the PKD2 gene - c.1124A>G, p.(Asn375Ser). Bioinformatic predictions of the functional effects of those three missense variants were inconsistent across different software tools. The family segregation analysis, which was mandatory to identify the relevant variant(s) for PGT-M, strongly supported that the disease-causing variant was PKD1 c.349T>G p.(Leu117Val), while the other two were nonpathogenic or, at most, phenotypic modulators. Proving the pathogenicity of novel variants is often complex but is critical to guide genetic counseling and screening, particularly when discussing reproductive alternatives for primary prevention in the progeny of at-risk couples. The family reported herein illustrates those challenges in the setting of ADPKD, and the invaluable importance of a detailed family history and segregation analysis for proper clinical annotation of novel variants. Basic genetic knowledge and proper clinical annotation of novel allelic variants in genes associated with hereditary kidney disorders are increasingly necessary for the contemporary practice of clinical nephrology.

Urinary Sediment Microscopy and Correlations with Kidney Biopsy: Red Flags Not To Be Missed.

BACKGROUND: Urinary sediment is a noninvasive laboratory test that can be performed by an automated analyzer or manually by trained personnel. Manual examination remains the diagnostic standard because it excels at differentiating isomorphic from dysmorphic red blood cells and identifying other urinary particles such as renal tubular epithelial cells (RTECs), lipids, crystals, and the composition of casts. This study aimed to investigate the prevalence of a complete profile of urinary sediment particles and its associations with histologic lesions on kidney biopsy, regardless of diagnosis. METHODS: This was a single-center, observational retrospective study of 131 patients who had contemporary manual urinary sediment evaluation and kidney biopsy. A comprehensive set of urinary particles and histologic lesions were quantified, and their associations were analyzed. RESULTS: In our samples, we found an elevated frequency of findings suggestive of proliferative kidney disease and a low frequency of particles evoking urologic damage. The association of histologic lesions and urinary particles was explored with a multivariate model. We identified urinary sediment characteristics that independently correlated with the presence of some histologic lesions: urinary lipids with mesangial expansion (OR=2.86; 95% confidence interval [95% CI], 1.3 to 6.3), mesangial hypercellularity (OR=2.44; 95% CI, 1.06 to 5.58), and wire loops and/or hyaline deposits (OR=2.89; 95% CI, 1.13 to 7.73); Urinary renal tubular epithelial cells with endocapillary hypercellularity (OR=3.17; 95% CI, 1.36 to 7.39), neutrophils and/or karyorrhexis (OR=4.51; 95% CI, 1.61 to 12.61), fibrinoid necrosis (OR=4.35; 95% CI, 1.48 to 12.74), cellular/fibrocellular crescents (OR=5.27; 95% CI, 1.95 to 14.26), and acute tubular necrosis (OR=2.31; 95% CI, 1.08 to 4.97). CONCLUSIONS: In a population of patients submitted to kidney biopsy, we found that the presence of some urinary particles (renal tubular epithelial cells, lipids, and dysmorphic erythrocytes), which are seldom reported by automated analyzers, is associated with active proliferative histologic lesions. In this regard, manual urinary sediment evaluation may help to shape the indications for performing a kidney biopsy.

Acute interstitial nephritis due to dolutegravir: The first case reported.

Kidney disease is frequent in HIV-patients. We present a case of a 44-year-old woman, with known uncontrolled HIV infection and chronic kidney disease due to HIV-associated nephropathy. After starting dolutegravir, the patient developed eosinophilia and worsening kidney function. A kidney biopsy confirmed the diagnosis of acute interstitial nephritis. Given the time relation with dolutegravir introduction, it was deemed the culprit medication. Dolutegravir was stopped, and corticosteroids were initiated, with moderate improvement in renal function. To our knowledge, this is the first reported case of acute interstitial nephritis to dolutegravir, which should raise awareness of previously undocumented renal effects of antiretroviral therapy.

Ulcerating stasis dermatitis of the forearm associated with arteriovenous graft and central vein stenosis.

INTRODUCTION: Stasis dermatitis is a pathologic condition of the skin that most commonly occurs in the lower limb, where it is caused by chronic venous insufficiency. Stasis dermatitis of the upper limb is rare. CASE REPORT: A 45-year-old male, resident in Angola, presented to the emergency department with an ulcer encompassing the entire left forearm. Past medical history comprised arterial hypertension and end stage renal disease treated with hemodialysis. Dialysis access consisted of a left brachial-basilic AV graft obtained 4 years before. The patient also reported that a right internal jugular vein catheter was used previously during the maturation of the left brachial-basilic AV graft. Stenosis of the left brachiocephalic vein was documented at angiography. Angioplasty was performed, with complete resolution of the wound 2 months after admission. CONCLUSION: The differential diagnosis of extensive ulcer of the forearm must include neoplasms, cellulitis, and/or deep tissue infection with secondary ulceration, but it is also important to maintain suspicion for venous stasis syndrome as a rare but possible cause of these lesions.

Complexes of In(III) with 8-hydroxyquinoline-5-sulfonate in solution: structural studies and the effect of cationic surfactants on the photophysical behaviour.

Following previous studies on the complexation in aqueous solutions of 8-hydroxyquinoline-5-sulfonate (8-HQS) with the trivalent metal ions, Al(III) and Ga(III) and various other metal ions, using multinuclear NMR, DFT calculations, UV-vis absorption and luminescence techniques, we have extended our studies on 8-HQS complexation to the trivalent metal ion In(III). The study combines the high sensitivity of luminescence techniques and the selectivity of multinuclear NMR spectroscopy with the structural details accessible through DFT calculations, and aims to obtain a complete understanding of the complexation between the In3+ metal ion and 8-HQS, and how this influences the luminescence behaviour. A full speciation study has been performed and, as has been reported for the complexes of 8-hydroxyquinoline (8-HQ), the dominant complexes of 8-HQS with In(III) show marked differences in the complexation behaviour when compared with the equivalent complexes with the other group 13 cations Al(III) and Ga(III). While all three complexes have a 1 : 3 (metal : ligand) stoichiometry, those with Al(III) and Ga(III) show a mer-geometry of the ligands around the metal centre, whereas the fac-geometry is observed for the complexes with In(III). On binding to metal ions, 8-HQS shows a marked increase in the intensity of the fluorescence emission band compared to that of the virtually non-luminescent free ligand. However, the increase for In(III) is less pronounced than with Al(III) or Ga(III). These observations have important implications for the application of the complexes in sensing, light emitting devices (e.g. OLEDs), or as electron transport layers in photovoltaics for solar energy conversion. Furthermore, surfactant complexation is known to improve the fluorescence intensity in metal complexes with 8-HQS, by inhibiting the ligand exchange, as we have reported for complexes of HQS with Al(III) and Ga(III). Accordingly, in view of the development of applications in either sensing or optoelectronics, our interest also includes the study of HQS complexes of In(III) in the presence of cationic surfactants, in comparison with previous results with Al(III) and Ga(III).

Outcomes of excessive alcohol drinkers without baseline evidence of chronic liver disease after 15 years follow-up: Heavy burden of cancer and liver disease mortality.

BACKGROUND: Most long-term heavy drinkers do not have clinically evident chronic liver disease (CLD). However, at any time-point, their risk of developing CLD remains unknown. We aimed to evaluate the long-term outcomes of a group of heavy drinkers, without evidence of CLD at baseline. METHODS: A cohort of 123 long-term heavy drinkers without CLD were prospectively recruited in 2002 and retrospectively followed until 2018. RESULTS: At baseline (2002), median alcohol consumption was 271±203g/day during 21.5±20 years, 65% being abstinent during the previous 1.75±5 months. Patients were followed for 14±3 years. During follow-up, 53% reported any alcohol intake. Alcohol consumption during follow-up associated weakly with either 1- or 6-months previous abstinence at baseline. Until 2018, progression to CLD occurred in 6%, associating with years of alcohol intake during follow-up (OR 1.15 [1.01-1.31]) and baseline alkaline-phosphatase (OR 1.05 [1.01-1.10]). During follow-up, being abstinent for at least 1 year positively associated with CLD-free survival. 27% died (55% of cancer-mostly oropharyngeal cancer, 27% of cardiovascular disease, and 9% of liver disease), with a mean age of 71 years [69-74] (10 years less than the expected in the Portuguese population). Achieving abstinence for at least 1 year positively associated with overall survival, while smoking, and hepatic steatosis at baseline associated negatively. CONCLUSION: Long-term heavy drinkers seemed to have a decreased life expectancy compared with the overall Portuguese population. Cancer was the main cause of death. Our results suggest that progression to CLD depends mostly on continued alcohol intake. Alcohol abstinence, even if temporary, seems to decrease the risks of CLD and mortality.

[A rare presentation of kidney allograft intolerance syndrome: Bullous pemphigoid]. / Une présentation rare du syndrome d'intolérance au greffon renal : la pemphigoïde bulleuse.

Bullous pemphigoid is an autoimmune bullous cutaneous disease. We report the case of a 60 year-old male patient whose kidney allograft failed and was on hemodialysis for the previous 16 months. After tapering immunosuppressive medication, he presented simultaneous bullous eruption and kidney allograft intolerance syndrome. Investigation showed a positive BP180 anti-basement membrane zone antibody and skin biopsy was consistent with bullous pemphigoid. The patient was treated with corticotherapy and bullous pemphigoid resolved. The development of new onset diabetes and concerns over long term immunosuppression, halted the decision to continue corticotherapy and the patient underwent graft nephrectomy, with resolution of the kidney allograft intolerance syndrome without recurrence of the bullous disease. The occurrence of bullous pemphigoid in patients with failed renal allograft is rare, with only eleven cases reported in literature. This case illustrates how graft nephrectomy can provide a definitive cure to bullous pemphigoid in this setting.

Oxocomplexes of U(vi) with 8-hydroxyquinoline-5-sulfonate in solution: structural studies and photophysical behaviour.

Multinuclear (1H and 13C) NMR, and Raman spectroscopy, combined with DFT calculations, provide detailed information on the complexation between U(vi) oxoions and 8-hydroxyquinoline-5-sulfonate (8-HQS) in aqueous solution. Over the concentration region studied, U(vi) oxoions (uranyl ions) form one dominant complex with 8-HQS in water in the pH range 3-6, a mononuclear 1 : 2 (metal : ligand) complex, with the metal centre (UO22+) coordinated to two 8-HQS ligands, together with one or more water molecules. An additional minor 1 : 1 complex has also been detected for solutions with a 1 : 1 metal : ligand molar ratio. The geometry of the dominant complex is proposed based on the combination of the NMR and Raman results with DFT calculations. Further information on the electronic structure of the complex has been obtained from UV/visible absorption and luminescence spectra. The complex of U(vi) and 8-HQS is non-luminescent, in contrast to what has been observed with this ligand and many other metal ions. We suggest that this is due to the presence of low-lying ligand-to-metal charge transfer (LMCT) states below the emitting ligand-based and uranyl-based levels which quench their emission. These studies have fundamental importance and are also relevant in the context of environmental studies, and the water soluble ligand 8-HQS has been chosen for application in uranium remediation of aqueous environments.