Reassuring pregnancy outcomes in women with mild COL4A3-5-related disease (Alport syndrome) and genetic type of disease can aid personalized counseling.

Individualized pre-pregnancy counseling and antenatal care for women with chronic kidney disease (CKD) require disease-specific data. Here, we investigated pregnancy outcomes and long-term kidney function in women with COL4A3-5 related disease (Alport Syndrome, (AS)) in a large multicenter cohort. The ALPART-network (mAternaL and fetal PregnAncy outcomes of women with AlpoRT syndrome), an international collaboration of 17 centers, retrospectively investigated COL4A3-5 related disease pregnancies after the 20th week. Outcomes were stratified per inheritance pattern (X-Linked AS (XLAS)), Autosomal Dominant AS (ADAS), or Autosomal Recessive AS (ARAS)). The influence of pregnancy on estimated glomerular filtration rate (eGFR)-slope was assessed in 192 pregnancies encompassing 116 women (121 with XLAS, 47 with ADAS, and 12 with ARAS). Median eGFR pre-pregnancy was over 90ml/min/1.73m2. Neonatal outcomes were favorable: 100% live births, median gestational age 39.0 weeks and mean birth weight 3135 grams. Gestational hypertension occurred during 23% of pregnancies (reference: 'general' CKD G1-G2 pregnancies incidence is 4-20%) and preeclampsia in 20%. The mean eGFR declined after pregnancy but remained within normal range (over 90ml/min/1.73m2). Pregnancy did not significantly affect eGFR-slope (pre-pregnancy ß=-1.030, post-pregnancy ß=-1.349). ARAS-pregnancies demonstrated less favorable outcomes (early preterm birth incidence 3/11 (27%)). ARAS was a significant independent predictor for lower birth weight and shorter duration of pregnancy, next to the classic predictors (pre-pregnancy kidney function, proteinuria, and chronic hypertension) though missing proteinuria values and the small ARAS-sample hindered analysis. This is the largest study to date on AS and pregnancy with reassuring results for mild AS, though inheritance patterns could be considered in counseling next to classic risk factors. Thus, our findings support personalized reproductive care and highlight the importance of investigating kidney disease-specific pregnancy outcomes.

Clinical Significance of the Cystic Phenotype in Alport Syndrome.

RATIONALE & OBJECTIVE: Alport syndrome (AS) is the most common genetic glomerular disease caused by mutations that affect type IV collagen. However, the clinical characteristics and significance of AS with kidney cysts are not well defined. This study investigated the prevalence and clinical significance of cystic kidney phenotype in AS. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: One hundred-eight patients with AS and a comparison cohort of 79 patients with IgA nephropathy (IgAN). Clinical, genetic, and imaging data were collected from medical records. EXPOSURE: Cystic kidney phenotype evaluated by ultrasonography and defined as the presence of≥3 cysts in each kidney; demographic characteristics and estimated glomerular filtration rate (eGFR) at disease onset. OUTCOME: Cystic kidney phenotype in the AS and IgAN cohorts; time to chronic kidney disease (CKD) stage 3b and longitudinal changes in eGFR in the AS cohort. ANALYTICAL APPROACH: Logistic regression analysis to test independent strengths of associations of clinical/demographic features with the binary outcome of cystic phenotype. Survival analysis for the outcome of reaching CKD stage 3b and linear mixed models for changes in eGFR over time in the AS cohort. RESULTS: We studied 108 patients with AS; 76 (70%) had a genetic diagnosis. Autosomal dominant AS was prevalent, accounting for 68% of patients with a genetic diagnosis. Cystic kidney phenotype was observed in 38% of patients with AS and was associated with normal-sized kidneys in all but 3 patients, who showed increased total kidney volume, mimicking autosomal dominant polycystic kidney disease. The prevalence of cystic kidney phenotype was significantly higher in patients with AS when compared with the group of patients with IgAN (42% vs 19%; P=0.002). Patients with the cystic kidney phenotype were older and had more marked reduction in eGFR than patients without cystic changes. Among patients with AS, the cystic phenotype was associated with older age and a faster decline eGFR. LIMITATIONS: Retrospective, single-center study. CONCLUSIONS: Cystic kidney phenotype is a common finding in AS. The cystic kidney phenotype is a common finding in AS, suggesting a possible role in cystogenesis for the genetic variants that cause this disease. PLAIN-LANGUAGE SUMMARY: Hematuria is the classic renal presentation of Alport syndrome (AS), a hereditary glomerulopathy caused by pathogenic variants of the COL4A3-5 genes. An atypical kidney cystic phenotype has been rarely reported in individuals with these variants. To determine the prevalence of kidney cysts, we performed abdominal ultrasonography in a large group of patients with AS and a comparison group of patients with another glomerular kidney disease, IgA nephropathy (IgAN). Multiple kidney cysts, usually with normal kidney volume, were found in 38% of patients with AS. A few patients' kidney volumes were large enough to mimic a different hereditary cystic kidney disease, autosomal dominant polycystic kidney disease. The overall prevalence of kidney cysts in AS was more than double that observed in the well-matched comparison group with IgAN. These findings emphasize the high prevalence of cystic kidney phenotype in AS, suggesting a likely association between the genetic variants that cause this disease and the development of kidney cysts.

Is there a dominant-negative effect in individuals with heterozygous disease-causing variants in COL4A3/COL4A4?

Alport syndrome (AS) shows a broad phenotypic spectrum ranging from isolated microscopic hematuria (MH) to end-stage kidney disease (ESKD). Monoallelic disease-causing variants in COL4A3/COL4A4 have been associated with autosomal dominant AS (ADAS) and biallelic variants with autosomal recessive AS (ARAS). The aim of this study was to analyze clinical and genetic data regarding a possible genotype-phenotype correlation in individuals with disease-causing variants in COL4A3/COL4A4. Eighty-nine individuals carrying at least one COL4A3/COL4A4 variant classified as (likely) pathogenic according to the American College of Medical Genetics guidelines and current amendments were recruited. Clinical data concerning the prevalence and age of first reported manifestation of MH, proteinuria, ESKD, and extrarenal manifestations were collected. Individuals with monoallelic non-truncating variants reported a significantly higher prevalence and earlier diagnosis of MH and proteinuria than individuals with monoallelic truncating variants. Individuals with biallelic variants were more severely affected than those with monoallelic variants. Those with biallelic truncating variants were more severely affected than those with compound heterozygous non-truncating/truncating variants or individuals with biallelic non-truncating variants. In this study an association of heterozygous non-truncating COL4A3/COL4A4 variants with a more severe phenotype in comparison to truncating variants could be shown indicating a potential dominant-negative effect as an explanation for this observation. The results for individuals with ARAS support the, still scarce, data in the literature.

Increased prevalence of Kidney cysts in individuals carrying heterozygous COL4A3 or COL4A4 pathogenic variants.

BACKGROUND: Clinical variability among individuals with heterozygous pathogenic/likely pathogenic (P/LP) variants in the COL4A3/COL4A4 genes (also called autosomal dominant Alport syndrome or COL4A3/COL4A4 related disorder) is huge; many individuals are asymptomatic or show microhematuria, while others may develop proteinuria and chronic kidney disease (CKD). The prevalence of simple kidney cysts (KC) in the general population varies according to age, and patients with advanced CKD are prone to have them. A possible association between heterozygous COL4A3, COL4A4, and COL4A5 P/LP variants and KC has been described in small cohorts. The presence of KC in a multicenter cohort of individuals with heterozygous P/LP variants in the COL4A3/COL4A4 genes is assessed in this study. METHODS: We evaluated the presence of KC by ultrasound in 157 individuals with P/LP variants in COL4A3 (40.7%) or COL4A4 (53.5%) without kidney replacement therapy. The association between presence of KC and age, proteinuria, eGFR, and causative gene was analyzed. Prevalence of KC was compared with historical case series in the general population. RESULTS: Half of the individuals with P/LP variants in COL4A3/COL4A4 showed KC, which is a significantly higher percentage than in the general population. Only 3.8% (6/157) had cystic nephromegaly. Age and eGFR showed an association with the presence of KC (p<0.001). No association was found between KC and proteinuria, sex, or causative gene. CONCLUSIONS: Individuals with COL4A3/COL4A4 P/LP variants are prone to develop KC more frequently than the general population, and their presence is related to age and to eGFR. Neither proteinuria, sex nor the causative gene influences the presence of KC in these individuals.

Liposome-lentivirus for miRNA therapy with molecular mechanism study.

BACKGROUND: Cancer stem cells (CSCs) play a vital role in the occurrence, maintenance, and recurrence of solid tumors. Although, miR-145-5p can inhibit CSCs survival, poor understanding of the underlying mechanisms hamperes further therapeutic optimization for patients. Lentivirus with remarkable transduction efficiency is the most commonly used RNA carrier in research, but has shown limited tumor-targeting capability. METHODS: We have applied liposome to decorate lentivirus surface thereby yielding liposome-lentivirus hybrid-based carriers, termed miR-145-5p-lentivirus nanoliposome (MRL145), and systematically analyzed their potential therapeutic effects on liver CSCs (LCSCs). RESULTS: MRL145 exhibited high delivery efficiency and potent anti-tumor efficacy under in vitro and in vivo. Mechanistically, the overexpressed miR-145-5p can significantly suppress the self-renewal, migration, and invasion abilities of LCSCs by targeting Collagen Type IV Alpha 3 Chain (COL4A3). Importantly, COL4A3 can promote phosphorylating GSK-3ß at ser 9 (p-GSK-3ß S9) to inactivate GSK3ß, and facilitate translocation of ß-catenin into the nucleus to activate the Wnt/ß-catenin pathway, thereby promoting self-renewal, migration, and invasion of LCSCs. Interestingly, COL4A3 could attenuate the cellular autophagy through modulating GSK3ß/Gli3/VMP1 axis to promote self-renewal, migration, and invasion of LCSCs. CONCLUSIONS: These findings provide new insights in mode of action of miR-145-5p in LCSCs therapy and indicates that liposome-virus hybrid carriers hold great promise in miRNA delivery.

Pseudodominant Alport syndrome caused by pathogenic homozygous and compound heterozygous COL4A3 splicing variants.

Alport syndrome is a genetic disorder affecting the basement membranes of the kidney, ear and eye, and represents a leading cause of monogenic kidney disease. Alport syndrome is genetically heterogeneous with three key genes involved (COL4A3-5) and several transmission patterns, including monogenic X-linked, autosomal recessive/dominant and digenic. We report a consanguineous family where 13 individuals presented variable features of Alport syndrome including kidney failure on two generations and male-to-male transmission, suggesting autosomal dominant inheritance. COL4A3-5 gene panel analysis surprisingly reveals two distinct, confirmed splice-altering variants in COL4A3 (NM_000091.4: c.1150+5G>A and c.4028-3C>T) present in homozygous or compound heterozygous state in individuals with kidney failure. This adds a further mode of transmission for Alport syndrome where, in a consanguineous family, the independent segregation of two variants at the same locus may create a pseudodominant transmission pattern. These findings highlight the importance of a molecular diagnosis in Alport syndrome for genetic risk counselling, given the variable modes of inheritance, but also the pitfalls of assuming identity by descent in consanguineous families.

Heterozygous COL4A3/COL4A4 mutations: the hidden part of the iceberg?

BACKGROUND: Single mutations in COL4A3/COL4A4 genes have been described in patients with autosomal dominant Alport syndrome and thin basement membrane nephropathy, without a shared definition of these patients within the medical community. We aimed to better categorize this clinical entity by examining clinical manifestations, family history, pathological features and genetics. METHODS: We retrospectively analyzed patients with causative heterozygous COL4A3/COL4A4 mutations referred to us between 1990 and 2019. Index cases were defined as children who were the first to be diagnosed in their families. RESULTS: The study included 24 index cases and 29 affected relatives, belonging to 25 families with a heterozygous mutation in the COL4A3/COL4A4 genes. During the follow-up, nine patients developed proteinuria [median age 15.7 years (range 5.6-33)], six at clinical diagnosis and four with progression toward chronic kidney disease (CKD) (three required kidney replacement therapy at 25, 45 and 53 years and one had CKD Stage 2 at 46 years). Extrarenal involvement was observed in 24.5% of patients. Hematuria was transmitted in consecutive generations, while CKD was reported in nonconsecutive generations of 11 families [median age 53 years (range 16-80)]. Seventeen patients (32%) underwent kidney biopsy: findings were consistent with Alport syndrome in 12 cases and with thin basement membrane nephropathy in 5 cases. CONCLUSIONS: Despite the benign course for these patients described in the literature, a significant percentage is at risk for disease progression. Consequently, we suggest that the assessment of these patients must take into account family history, genetic analysis and pathologic findings. After comparison with the literature, our data suggest that a different definition for Alport syndrome must be considered.

Disruption of the glomerular basement membrane associated with nutcracker syndrome and double inferior vena cava in Noonan syndrome: a case report.

BACKGROUND: Nutcracker syndrome (NCS) is characterized by compression of the left renal vein (LRV) between the aorta and the superior mesenteric artery. While rare, NCS was reported to be accompanied by double inferior vena cava (IVC). We herein report a case of Noonan syndrome (NS) with double IVC who presented with macrohematuria and proteinuria. CASE PRESENTATION: The patient was a 23-year-old man, who had been diagnosed with NS due to RIT1 mutation, after showing foamy macrohematuria 3 weeks previously. A physical examination revealed low-set ears and a webbed neck. A urinalysis showed hematuria and proteinuria, and urinary sediments showed more than 100 isomorphic red blood cells per high-power field. His proteinuria and albuminuria concentrations were 7.1 and 4.5 g/g⋅Cr, respectively. Three-dimensional contrast-enhanced computed tomography (CT) showed double IVC and narrowing of the LRV after interflow of the left IVC. The aortomesenteric angle on a sagittal reconstruction of the CT image was 14.7°. Cystoscopy revealed a flow of macrohematuria from the left ureteral opening. On Doppler ultrasonography, there was scant evidence to raise the suspicion of the nutcracker phenomenon. Since severe albuminuria continued, a left kidney biopsy was performed. Light microscopy showed red blood cells in Bowman's space and the tubular lumen. Electron microscopy revealed disruption of the glomerular basement membrane (GBM). Vulnerability of the GBM was suspected and a genetic analysis revealed a heterozygous mutation at c.4793 T > G (p.L1598R) in the COL4A3 gene. Screening for coagulation disorders revealed the factor VIII and von Willebrand factor (vWF) values were low, at 47.6 and 23%, respectively. A multimer analysis of vWF showed a normal multimer pattern and he was diagnosed with von Willebrand disease type 1. As the bleeding tendency was mild, replacement of factor VIII was not performed. His macrohematuria and proteinuria improved gradually without treatment, and his urinalysis results have been normal for more than 6 months. CONCLUSIONS: The present case showed macrohematuria and proteinuria due to NCS in NS with double IVC and von Willebrand disease type 1. The macrohematuria and proteinuria originated from glomerular hemorrhage because of vulnerability of the GBM due to COL4A3 mutation.

Prevalence Estimates of Predicted Pathogenic COL4A3-COL4A5 Variants in a Population Sequencing Database and Their Implications for Alport Syndrome.

BACKGROUND: The reported prevalence of Alport syndrome varies from one in 5000 to one in 53,000 individuals. This study estimated the frequencies of predicted pathogenic COL4A3-COL4A5 variants in sequencing databases of populations without known kidney disease. METHODS: Predicted pathogenic variants were identified using filtering steps based on the ACMG/AMP criteria, which considered collagen IV α3-α5 position 1 Gly to be critical domains. The population frequencies of predicted pathogenic COL4A3-COL4A5 variants were then determined per mean number of sequenced alleles. Population frequencies for compound heterozygous and digenic combinations were calculated from the results for heterozygous variants. RESULTS: COL4A3-COL4A5 variants resulting in position 1 Gly substitutions were confirmed to be associated with hematuria (for each, P<0.001). Predicted pathogenic COL4A5 variants were found in at least one in 2320 individuals. p.(Gly624Asp) represented nearly half (16 of 33, 48%) of the variants in Europeans. Most COL4A5 variants (54 of 59, 92%) had a biochemical feature that potentially mitigated the clinical effect. The predicted pathogenic heterozygous COL4A3 and COL4A4 variants affected one in 106 of the population, consistent with the finding of thin basement membrane nephropathy in normal donor kidney biopsy specimens. Predicted pathogenic compound heterozygous variants occurred in one in 88,866 individuals, and digenic variants in at least one in 44,793. CONCLUSIONS: The population frequencies for Alport syndrome are suggested by the frequencies of predicted pathogenic COL4A3-COL4A5 variants, but must be adjusted for the disease penetrance of individual variants and for the likelihood of already diagnosed disease and non-Gly substitutions. Disease penetrance may depend on other genetic and environmental factors.

Natural Ligand-Mimetic and Nonmimetic Inhibitors of the Ceramide Transport Protein CERT.

Lipid transfer proteins (LTPs) are recognized as key players in the inter-organelle trafficking of lipids and are rapidly gaining attention as a novel molecular target for medicinal products. In mammalian cells, ceramide is newly synthesized in the endoplasmic reticulum (ER) and converted to sphingomyelin in the trans-Golgi regions. The ceramide transport protein CERT, a typical LTP, mediates the ER-to-Golgi transport of ceramide at an ER-distal Golgi membrane contact zone. About 20 years ago, a potent inhibitor of CERT, named (1R,3S)-HPA-12, was found by coincidence among ceramide analogs. Since then, various ceramide-resembling compounds have been found to act as CERT inhibitors. Nevertheless, the inevitable issue remains that natural ligand-mimetic compounds might directly bind both to the desired target and to various undesired targets that share the same natural ligand. To resolve this issue, a ceramide-unrelated compound named E16A, or (1S,2R)-HPCB-5, that potently inhibits the function of CERT has recently been developed, employing a series of in silico docking simulations, efficient chemical synthesis, quantitative affinity analysis, protein-ligand co-crystallography, and various in vivo assays. (1R,3S)-HPA-12 and E16A together provide a robust tool to discriminate on-target effects on CERT from off-target effects. This short review article will describe the history of the development of (1R,3S)-HPA-12 and E16A, summarize other CERT inhibitors, and discuss their possible applications.

Clinical and Genetic Features of Autosomal Dominant Alport Syndrome: A Cohort Study.

RATIONALE & OBJECTIVE: Alport syndrome is a common genetic kidney disease accounting for approximately 2% of patients receiving kidney replacement therapy (KRT). It is caused by pathogenic variants in the gene COL4A3, COL4A4, or COL4A5. The aim of this study was to evaluate the clinical and genetic spectrum of patients with autosomal dominant Alport syndrome (ADAS). STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 82 families (252 patients) with ADAS were studied. Clinical, genetic, laboratory, and pathology data were collected. OBSERVATIONS: A pathogenic DNA variant in COL4A3 was identified in 107 patients (35 families), whereas 133 harbored a pathogenic variant in COL4A4 (43 families). Digenic/complex inheritance was observed in 12 patients. Overall, the median kidney survival was 67 (95% CI, 58-73) years, without significant differences across sex (P=0.8), causative genes (P=0.6), or type of variant (P=0.9). Microhematuria was the most common kidney manifestation (92.1%), and extrarenal features were rare. Findings on kidney biopsies ranged from normal to focal segmental glomerulosclerosis. The slope of estimated glomerular filtration rate change was-1.46 (-1.66 to-1.26) mL/min/1.73m2 per year for the overall group, with no significant differences between ADAS genes (P=0.2). LIMITATIONS: The relatively small size of this series from a single country, potentially limiting generalizability. CONCLUSIONS: Patients with ADAS have a wide spectrum of clinical presentations, ranging from asymptomatic to kidney failure, a pattern not clearly related to the causative gene or type of variant. The diversity of ADAS phenotypes contributes to its underdiagnosis in clinical practice.

Pathogenic Variants in the Genes Affected in Alport Syndrome (COL4A3-COL4A5) and Their Association With Other Kidney Conditions: A Review.

Massively parallel sequencing identifies pathogenic variants in the genes affected in Alport syndrome (COL4A3-COL4A5) in as many as 30% of individuals with focal and segmental glomerulosclerosis (FSGS), 10% of those with kidney failure of unknown cause, and 20% with familial immunoglobulin A (IgA) glomerulonephritis. FSGS associated with COL4A3-COL4A5 variants is usually present by the onset of kidney failure and may develop because the abnormal glomerular membranes result in podocyte loss and secondary hyperfiltration. The association of COL4A3-COL4A5 variants with kidney failure or IgA glomerulonephritis may be coincidental. However, pathogenic variants in these conditions occur more often than they should by chance, which suggests that the variants are disease-causing. COL4A3-COL4A5 variants are also found in cystic kidney diseases after autosomal dominant polycystic kidney disease has been excluded. COL4A3-COL4A5 variants should be suspected in individuals with FSGS, kidney failure of unknown cause, or familial IgA glomerulonephritis, especially where there is persistent hematuria and a family history of hematuria or kidney failure.

Alport Syndrome: Achieving Early Diagnosis and Treatment.

Alport syndrome is a genetically and phenotypically heterogeneous disorder of glomerular, cochlear, and ocular basement membranes resulting from mutations in the collagen IV genes COL4A3, COL4A4, and COL4A5. Alport syndrome can be transmitted as an X-linked, autosomal recessive, or autosomal dominant disorder. Individuals with Alport syndrome have a significant lifetime risk for kidney failure, as well as sensorineural deafness and ocular abnormalities. The availability of effective intervention for Alport syndrome-related kidney disease makes early diagnosis crucial, but this can be impeded by the genotypic and phenotypic complexity of the disorder. This review presents an approach to enhancing early diagnosis and achieving optimal outcomes.

Precise variant interpretation, phenotype ascertainment, and genotype-phenotype correlation of children in the EARLY PRO-TECT Alport trial.

Early initiation of therapy in patients with Alport syndrome (AS) slows down renal failure by many years. Genotype-phenotype correlations propose that the location and character of the individual's variant correlate with the renal outcome and any extra renal manifestations. In-depth clinical and genetic data of 60/62 children who participated in the EARLY PRO-TECT Alport trial were analyzed. Genetic variants were interpreted according to current guidelines and criteria. Genetically solved patients with X-linked inheritance were then classified according to the severity of their COL4A5 variant into less-severe, intermediate, and severe groups and disease progress was compared. Almost 90% of patients were found to carry (likely) pathogenic variants and classified as genetically solved cases. Patients in the less-severe group demonstrated a borderline significant difference in disease progress compared to those in the severe group (p = 0.05). While having only limited power according to its sample size, an obvious strength is the precise clinical and genetic data of this well ascertained cohort. As in published data differences in clinical progress were shown between patients with COL4A5 less-severe and severe variants. Therefore, clinical and segregational data are important for variant (re)classification. Genetic testing should be mandatory allowing early diagnosis and therapy of AS.

Genotype-phenotype correlations and nephroprotective effects of RAAS inhibition in patients with autosomal recessive Alport syndrome.

BACKGROUND: Autosomal recessive Alport syndrome (ARAS) is caused by pathogenic variants in both alleles of either COL4A3 or COL4A4 genes. Reports on ARAS are rare due to small patient numbers and there are no reports on renin-angiotensin-aldosterone system (RAAS) inhibition therapy in ARAS. METHODS: Retrospective study in 101 patients with ARAS from Chinese Registry Database of Hereditary Kidney Diseases and European Alport Registry. Genotype-phenotype correlations and nephroprotective effects of RAAS inhibition in ARAS were evaluated. RESULTS: Median age was 15 years (range 1.5-46 years). Twelve patients progressed to stage 5 chronic kidney disease (CKD5) at median age 20.5 years. Patients without missense variants had both higher prevalence and earlier onset age of hearing loss, nephrotic-range proteinuria, more rapid decline of eGFR, and earlier onset age of CKD5 compared to patients with 1 or 2 missense variants. Most patients (79/101, 78%) currently are treated with RAAS inhibitors; median age at therapy initiation was 10 years and mean duration 6.5 ± 6.0 years. Median age at CKD5 for untreated patients was 24 years. RAAS inhibition therapy delayed CKD5 onset in those with impaired kidney function (T-III) to median age 35 years, but is undefined in treated patients with proteinuria (T-II) due to low number of events. No treated patients with microalbuminuria (T-I) progressed to CKD5. ARAS patients with 1 or 2 missense variants showed better response to treatment than patients with non-missense-variants. CONCLUSIONS: Our study provides the first evidence for early use of RAAS inhibition therapy in patients with ARAS. Furthermore, genotype in ARAS correlates with response to therapy in favor of missense variants.

COL1A1, COL4A3, TIMP2 and TGFB1 polymorphisms in cervical insufficiency.

OBJECTIVES: To investigate the association between selected single nucleotide polymorphisms (SNPs) with cervical insufficiency and its relationship with obstetric history. METHODS: Twenty-eight women with cervical insufficiency (case group) and 29 non-pregnant women (control group) were included. The SNPs sequenced included rs2586490 in collagen type I alpha 1 chain (COL1A1), rs1882435 in collagen type IV alpha 3 chain (COL4A3), rs2277698 in metallopeptidase inhibitor 2 (TIMP2), and rs1800468 in transforming growth factor beta 1 (TGFB1). RESULTS: We found a higher frequency of the normal allele in the control group (65.5%) and the homozygous mutated genotype in the case group (64.3%) for rs2586490 in COL1A1 (p=0.023). An unplanned finding in the cervical insufficiency group was a higher gestational age of delivery (median≥38 weeks) in the mutated allele than in the wild-type genotype (median of 28.2 weeks) for rs2857396, which is also in the COL1A1 gene (p=0.011). CONCLUSIONS: The findings of the present study corroborate the hypothesis that cervical insufficiency has a genetic component and probably involves genes encoding proteins in the extracellular matrix, in addition to inflammatory processes.

The importance of clinician, patient and researcher collaborations in Alport syndrome.

Alport syndrome is caused by mutations in the genes COL4A3, COL4A4 or COL4A5 and is characterised by progressive glomerular disease, sensorineural hearing loss and ocular defects. Occurring in less than 1:5000, Alport syndrome is a rare genetic disorder but still accounts for > 1% of the prevalent population receiving renal replacement therapy. There is also increasing awareness about the risk of chronic kidney disease in individuals with heterozygous mutations in Alport syndrome genes. The mainstay of current therapy is the use of angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, yet potential new therapies are now entering clinical trials. The 2017 International Workshop on Alport Syndrome in Glasgow was a pre-conference workshop ahead of the 50th anniversary meeting of the European Society for Pediatric Nephrology. It focussed on updates in clinical practice, genetics and basic science and also incorporated patient perspectives. More than 80 international experts including clinicians, geneticists, researchers from academia and industry, and patient representatives took part in panel discussions and breakout groups. This report summarises the workshop proceedings and the relevant contemporary literature. It highlights the unique clinician, patient and researcher collaborations achieved by regular engagement between the groups.

How to resolve confusion in the clinical setting for the diagnosis of heterozygous COL4A3 or COL4A4 gene variants? Discussion and suggestions from nephrologists.

Both thin basement membrane nephropathy (TBMN) and autosomal dominant Alport syndrome (ADAS) are types of hereditary nephritis resulting from heterozygous mutations in COL4A3 or COL4A4 genes. Although TBMN is characterized by hematuria and thinning of the glomerular basement membrane (GBM) with excellent renal prognosis, some patients develop end-stage renal disease (ESRD) later in life. In contrast, although AS is characterized by progressive nephropathy with lamellation of the GBM, there are some patients diagnosed with ADAS from a family history of ESRD but who only suffer from hematuria with GBM thinning. These findings indicate a limitation in distinction between TBMN and ADAS. Diagnosis of AS is significant because it facilitates careful follow-up and early treatment, whereas diagnosis of TBMN can underestimate the risk of ESRD. However, some experts are against using the term ADAS as the phenotypes of heterozygous variants vary from no urinary abnormality to ESRD, even between family members with the same mutations, indicating that unknown secondary factors may play a large role in the disease severity. These diagnostic difficulties result in significant confusion in clinical settings. Moreover, recent studies revealed that the number of patients with chronic kidney disease caused by these gene mutations is far higher than previously thought. The aim of this article is to review differing opinions regarding the diagnosis of heterozygous COL4A3 or COL4A4 variants, and to highlight the importance for nephrologists to recognize this disease, and the importance of the need to reclassify this disease to minimize the current confusion.

Alport syndrome: Proteomic analysis identifies early molecular pathway alterations in Col4a3 knock out mice.

AIM: Alport syndrome (AS) is the second most common hereditary kidney disease caused by mutations in collagen IV genes. Patients present with microhaematuria that progressively leads to proteinuria and end stage renal disease. Currently, no specific treatment exists for AS. Using mass spectrometry based proteomics, we aimed to detect early alterations in molecular pathways implicated in AS before the stage of overt proteinuria, which could be amenable to therapeutic intervention. METHODS: Kidneys were harvested from male Col4a3-/- knock out and sex and age-matched Col4a3+/+ wild-type mice at 4 weeks of age. Purified peptides were separated by liquid chromatography and analysed by high resolution mass spectrometry. The Cytoscape bioinformatics tool was used for function enrichment and pathway analysis. PPARα expression levels were evaluated by immunofluorescence and immunoblotting. RESULTS: Proteomic analysis identified 415 significantly differentially expressed proteins, which were mainly involved in metabolic and cellular processes, the extracellular matrix, binding and catalytic activity. Pathway enrichment analysis revealed among others, downregulation of the proteasome and PPAR pathways. PPARα protein expression levels were observed to be downregulated in Alport mice, supporting further the results of the discovery proteomics. CONCLUSION: This study provides additional evidence that alterations in proteins which participate in cellular metabolism and mitochondrial homeostasis in kidney cells are early events in the development of chronic kidney disease in AS. Of note is the dysregulation of the PPAR pathway, which is amenable to therapeutic intervention and provides a new potential target for therapy in AS.

CG200745, a Novel HDAC Inhibitor, Attenuates Kidney Fibrosis in a Murine Model of Alport Syndrome.

Histone deacetylases have been a target of therapy for organ fibrosis. Here, we report the protective effect of CG200745 (CG), a novel histone deacetylase inhibitor, on tubulointerstitial fibrosis in Col4a3-/- mice, a murine model of Alport syndrome. Morphological analyses revealed CG treatment markedly alleviated kidney fibrosis in Col4a3-/- mice at the age of 7 weeks. CG prevented the activation of transforming growth factor ß (TGFß) and its downstream SMAD signaling in the kidney of Col4a3-/- mice. As critical upstream regulators of TGFß signaling, immunoblotting of whole kidney lysate of Col4a3-/- mice reveled that intra-renal renin-angiotensin system (RAS) was activated with concurrent upregulation of inflammation and apoptosis, which were effectively suppressed by CG treatment. CG suppressed both activation of RAS and up-regulation of TGFß signals in angiotensin II-stimulated HK-2 cells, a human kidney proximal tubular epithelial cell line. CG inhibited activation of TGFß-driven signals and fibrosis in NRK-49F cells, a rat kidney fibroblast cell line, under angiotensin II-rich conditions. Collectively, CG was found to be effective both in proximal tubular epithelial cells by inhibiting local RAS and TGFß signaling activation, as well as in fibroblasts by blocking their transition to myofibroblasts, attenuating renal fibrosis in a murine model of Alport syndrome.