Epidemiology and risk factors for resistance to treatment of Kawasaki disease in Cyprus

Kawasaki disease (KD) is one of the most common vasculitides of early childhood. There are no previous studies on KD in Cyprus. The aim of this study was to evaluate the epidemiology of KD in Cyprus, risk factors for resistance to treatment and the development of cardiac complications. This is a retrospective multicenter study of pediatric patients with KD hospitalized between January 2000 and-December 2019. The data were collected from medical records. A total of 136 patients with KD were included in the study. 83% of patients were < 5 years of age and 10% were < 6 months. Thirty patients (22%) developed coronary artery lesions. Serum sodium ≤ 133 mmol/L, albumin ≤ 3.2 g/dl, ALT ≥ 80 U/L and neutrophils percentage ≥ 80% at diagnosis, were identified as risk factors for resistance to IVIG. Clinical and epidemiological characteristics of KD in Cyprus population were similar to those reported in the literature. Although the majority of cases received appropriate treatment in time, cardiac complications still occurred

COL4A5 and LAMA5 variants co-inherited in familial hematuria: digenic inheritance or genetic modifier effect?

Abstract Background About 40–50% of patients with familial microscopic hematuria (FMH) caused by thin basement membrane nephropathy (TBMN) inherit heterozygous mutations in collagen IV genes (COL4A3, COL4A4). On long follow-up, the full phenotypic spectrum of these patients varies a lot, ranging from isolated MH or MH plus low-grade proteinuria to chronic renal failure of variable degree, including end-stage renal disease (ESRD). Methods Here, we performed Whole Exome Sequencing (WES) in patients of six families, presenting with autosomal dominant FMH, with or without progression to proteinuria and loss of renal function, all previously found negative for severe collagen IV mutations. Hierarchical filtering of the WES data was performed, followed by mutation prediction analysis, Sanger sequencing and genetic segregation analysis. Results In one family with four patients, we found evidence for the contribution of two co-inherited variants in two crucial genes expressed in the glomerular basement membrane (GBM); LAMA5-p.Pro1243Leu and COL4A5-p.Asp654Tyr. Mutations in COL4A5 cause classical X-linked Alport Syndrome, while rare mutations in the LAMA5 have been reported in patients with focal segmental glomerulosclerosis. The phenotypic spectrum of the patients includes hematuria, proteinuria, focal segmental glomerulosclerosis, loss of kidney function and renal cortical cysts. Conclusions A modifier role of LAMA5 on the background of a hypomorphic Alport syndrome causing mutation is a possible explanation of our findings. Digenic inheritance is another scenario, following the concept that mutations at both loci more accurately explain the spectrum of symptoms, but further investigation is needed under this concept. This is the third report linking a LAMA5 variant with human renal disease and expanding the spectrum of genes involved in glomerular pathologies accompanied by familial hematurias. The cystic phenotype overlaps with that of a mouse model, which carried a Lama5 hypomorphic mutation that caused severely reduced Lama5 protein levels and produced kidney cysts

Clinico-pathological correlations in 127 patients in 11 large pedigrees, segregating one of three heterozygous mutations in the COL4A3/ COL4A4 genes associated with familial haematuria and significant late progression to proteinuria and chronic kidney disease from focal segmental glomerulosclerosis

&lt;p&gt;&lt;strong&gt;Background.&lt;/strong&gt; Heterozygous mutations in the &lt;i&gt;COL4A3/ COL4A4&lt;/i&gt; genes are currently thought to be responsible for familial benign microscopic haematuria and maintenance of normal long-term kidney function.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods.&lt;/strong&gt; We report on 11 large Cypriot pedigrees with three such mutations. A total of 236 at-risk family members were genetically studied, and 127 (53.8%) carried a heterozygous mutation. Clinico-pathological correlations were available in all of these patients. Renal biopsies in 21 of these patients all showed various stages of focal, segmental glomerulosclerosis (FSGS). Thirteen of these biopsies were also studied with EM and showed thinning of the glomerular basement membrane.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results.&lt;/strong&gt; Mutation G1334E (&lt;i&gt;COL4A3&lt;/i&gt;) was found in six pedigrees, mutation G871C (&lt;i&gt;COL4A3&lt;/i&gt;) in four and mutation 3854delG (&lt;i&gt;COL4A4&lt;/i&gt;) in one pedigree. Clinical and laboratory correlations in all 127 mutation carriers (MC) showed that microscopic haematuria was the only urinary finding in patients under age 30. The prevalence of 'haematuria alone' fell to 66% between 31 and 50 years, to 30% between 51 and 70 and to 23% over age 71. Proteinuria with CRF developed on top of haematuria in 8% of all MC between 31 and 50 years, to 25% between 51 and 70 years and to 50% over 71 years. Altogether 18 of these 127 MC (14%) developed ESRD at a mean age of 60 years. Two members with different mutations married, and two of their children inherited both mutations and developed adolescent, autosomal recessive Alport syndrome (ATS), confirming that these mutations are pathogenic.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions.&lt;/strong&gt; Our data confirm for the first time a definite association of heterozygous &lt;i&gt;COL4A3/COL4A4&lt;/i&gt; mutations with familial microscopic haematuria, thin basement membrane nephropathy and the late development of familial proteinuria, CRF, and ESRD, due to FSGS, indicating that the term 'benign familial haematuria' is a misnomer, at least in this cohort. A strong hypothesis for a causal relationship between these mutations and FSGS is also made. Benign familial haematuria may not be so benign as commonly thought.&lt;/p&gt

Additional file 1: of COL4A5 and LAMA5 variants co-inherited in familial hematuria: digenic inheritance or genetic modifier effect?

WES statistics. Number of genetic variants called after the WES analysis. (DOCX 15 kb

Description of cohorts and patients under study.

<p>Please note that cohort B1 is the male only patients with CFHR5 nephropathy.</p><p>MH: Microscopic Hematuria, ESKD: End Stage Kidney Disease, XLAS: X-linked Alport syndrome.</p>1<p>“Mild” patients born before 01/1963. Gender difference (Mild vs Severe) is not significant (p = 0.141).</p>2<p>“Mild” patients born before 01/1975. Gender difference (Mild vs Severe) is significant (p = 0.001).</p>3<p>“Severe” patients: ESKD≤40 yo.</p>4<p>“Mild” patients born before 01/1979. Gender difference (Mild vs Severe) is significant (p = 0.001).</p

Genotype associations for the three <i>MYH9</i> variants genotyped in this study.

<p>P-values were calculated by Pearson Chi-Square test. The whole CFHR5 cohort (B) was genotyped only for <i>MYH9</i> rs11089788, the only SNP that gave p-value close to 0.1 for the male CFHR5 patients (B1).</p>*<p>P-values calculated by Fisher's Exact Test (2-sided) due to existence of genotypes values less than 10.</p>**<p>Odds ratio (OR) cannot be estimated due to zero genotypic values in the “Severe” category.</p

Genotype distribution of the studied <i>MYH9</i> variants, by cohort and by severity.

<p>Genotype distribution of the studied <i>MYH9</i> variants, by cohort and by severity.</p

<i>MYH9</i> rs11089788 statistical analysis for a replicate cohort (D) and for the sum of cohorts B and D, that gave statistical significance.

<p>Patients in cohort D belong to families that segregate microscopic hematuria but no known mutation has been found in any of the genes <i>COL4A3</i>, <i>COL4A4</i>, or <i>CFHR5</i>, so far.</p

Frequency of COL4A3/COL4A4 mutations amongst families segregating glomerular microscopic hematuria and evidence for activation of the unfolded protein response. Focal and segmental glomerulosclerosis is a frequent development during ageing.

Familial glomerular hematuria(s) comprise a genetically heterogeneous group of conditions which include Alport Syndrome (AS) and thin basement membrane nephropathy (TBMN). Here we investigated 57 Greek-Cypriot families presenting glomerular microscopic hematuria (GMH), with or without proteinuria or chronic kidney function decline, but excluded classical AS. We specifically searched the COL4A3/A4 genes and identified 8 heterozygous mutations in 16 families (28,1%). Eight non-related families featured the founder mutation COL4A3-p.(G1334E). Renal biopsies from 8 patients showed TBMN and focal segmental glomerulosclerosis (FSGS). Ten patients (11.5%) reached end-stage kidney disease (ESKD) at ages ranging from 37-69-yo (mean 50,1-yo). Next generation sequencing of the patients who progressed to ESKD failed to reveal a second mutation in any of the COL4A3/A4/A5 genes, supporting that true heterozygosity for COL4A3/A4 mutations predisposes to CRF/ESKD. Although this could be viewed as a milder and late-onset form of autosomal dominant AS, we had no evidence of ultrastructural features or extrarenal manifestations that would justify this diagnosis. Functional studies in cultured podocytes transfected with wild type or mutant COL4A3 chains showed retention of mutant collagens and differential activation of the unfolded protein response (UPR) cascade. This signifies the potential role of the UPR cascade in modulating the final phenotype in patients with collagen IV nephropathies