Genetic and Epigenetic Biomarkers Linking Alzheimer's Disease and Age-Related Macular Degeneration.

Alzheimer's disease (AD) represents a prominent neurodegenerative disorder (NDD), accounting for the majority of dementia cases worldwide. In addition to memory deficits, individuals with AD also experience alterations in the visual system. As the retina is an extension of the central nervous system (CNS), the loss in retinal ganglion cells manifests clinically as decreased visual acuity, narrowed visual field, and reduced contrast sensitivity. Among the extensively studied retinal disorders, age-related macular degeneration (AMD) shares numerous aging processes and risk factors with NDDs such as cognitive impairment that occurs in AD. Histopathological investigations have revealed similarities in pathological deposits found in the retina and brain of patients with AD and AMD. Cellular aging processes demonstrate similar associations with organelles and signaling pathways in retinal and brain tissues. Despite these similarities, there are distinct genetic backgrounds underlying these diseases. This review comprehensively explores the genetic similarities and differences between AMD and AD. The purpose of this review is to discuss the parallels and differences between AMD and AD in terms of pathophysiology, genetics, and epigenetics.

Genetic and Epigenetic Features of Uveal Melanoma-An Overview and Clinical Implications.

Uveal melanoma (UM) is rare, but it is the most common primary intraocular malignancy among adults. This review represents the molecular, genetic, and immunobiological mechanisms involved in UM carcinogenesis and progression, as well as data about the association of chromosomal changes, genetic mutations, selective proteins, and biochemical biomarkers with the clinical implications of UM. Genetic analysis has the potential to identify patients with a high risk of UM metastasis, enabling management that is more effective and allowing for the follow-up of patients. Advancements in molecular characterization of UM offer opportunities to develop targeted therapeutic strategies by focusing on relevant signaling pathways. Changes in miRNA expression could be useful in the diagnosis and prognosis of UM, due to unique miRNA profiles in melanoma cells or tissue and its association with metastasis. Although liver function tests do not provide enough data on the prognosis of UM, due to the high frequency of liver metastasis, liver function tests (LFTs) might be useful indicators; however, the absence of rising LFT values cannot lead to the exclusion of liver metastases. Molecular analysis of tumor tissue will allow us to identify patients with the added benefit of new therapeutic agents and provide a better insight into melanoma pathogenesis and its biological behavior.

Clinical and pathohistological characteristics of Alport spectrum disorder caused by COL4A4 mutation c.193-2A>C: a case series.

AIM: To present the pathohistological and clinical characteristics of five Croatian families with Alport spectrum disorders caused by splice acceptor pathogenic variant c.193-2A>C in COL4A4 at the genomic position chr2:227985866. METHODS: The study enrolled five probands with kidney biopsy analysis and five family members. Mutation screening was performed with Illumina MiSeq platform. The pathogenic variant was confirmed with standard dye-terminator sequencing. RESULTS: The only homozygous patient, aged two, had proteinuria and hematuria with preserved kidney function and no extrarenal manifestations. This patient had changes characteristic for Alport syndrome observed on electron microscopy of the kidney biopsy. In the heterozygous group, six patients had hematuria, four biopsied probands had proteinuria, and only one had moderately reduced kidney function. Heterozygous probands had variable kidney biopsy findings. Three patients had thin glomerular basement membrane nephropathy visible on electron microscopy and focal segmental glomerulosclerosis on light microscopy, two of them with focal lamellation on electron microscopy. One heterozygous patient had changes characteristic for Alport syndrome on electron microscopy without focal segmental glomerulosclerosis. CONCLUSION: The homozygous patient had hematuria and proteinuria with preserved kidney function. The heterozygous patients presented with reasonably mild clinical phenotype and variable pathohistological findings.

THE FREQUENCY OF FOLLICLE-STIMULATING HORMONE RECEPTOR 2039A>G GENE POLYMORPHISM AND THE RISK OF MALE INFERTILITY IN ALBANIAN POPULATION.

The purpose of this study was to determine the prevalence of allele and genotype variants of the follicle-stimulating hormone receptor (FSHR) gene polymorphic region at position Asn680Ser in the Albanian male population and associate them with the clinical parameters of infertility. The study included 114 infertile men (mean age 35.04±5.85 years) stratified according to the level of spermatogenetic impairment (oligoasthenozoospermia, asthenozoospermia and normospermia) and 112 fertile men (mean age 36.44±7.05 years) with normal semen parameters. Genotyping of the FSHR gene at position 680 was performed by TaqMan genotyping assay. All the participants underwent semen analysis, and serum reproductive hormones (FSH, luteinizing hormone, prolactin and testosterone) were also measured. The FSHR Asn680Ser genotype frequencies were as follows: Asn/Ser 42%, Ser/Ser 33.9% and Asn/Asn 24.1% in the control group, and Asn/Ser 56.1%, Ser/Ser 22.8% and Asn/Asn 21.1% in the whole group of infertile men (χ2-test: P=0.08). There was no statistically significant correlation between serum hormone levels and semen characteristics or between fertility status and FSHR Asn680Ser gene variants in the control group and the group of infertile men. However, adjusted logistic regression analysis (age, body mass index, smoking and alcohol as covariates) revealed increased odds ratio for male infertility among heterozygous Asn/Ser genotype carriers associated with lower values of semen parameters (normal morphology, concentration, total sperm count and motility). In conclusion, our case-control study further confirmed previous reports on no significant association between the FSHR Asn680Ser polymorphisms and male infertility. Nevertheless, the data presented herein indicate that the Asn/Ser genotype may increase the risk of male infertility in Albanian population.

Autosomal recessive Alport syndrome caused by a novel COL4A4 splice site mutation: a case report.

Alport syndrome (AS) is a genetically heterogenic, structural disorder of the glomerular basement membrane (GBM) due to the mutation of COL4A3, COL4A4, or COL4A5 genes, which clinically presents as progressive hematuric nephritis with ultrastructural changes of the GBM, high tone sensorineural hearing loss, and ocular lesions. About 15% of AS cases have autosomal mutations of COL4A3 and COL4A4 genes, including homozygous and compound heterozygous mutations. Here, we present a case of a two-year-old boy with autosomal recessive Alport syndrome (ARAS) caused by a novel c.193-2A>C COL4A4 mutation. The patient had a delayed motor and sensory development coupled with speech and language delay, megalencephaly, hematuria and proteinuria, and normal tonal audiogram and ophthalmology exam. Extensive genetic, metabolic, and neurologic workup performed at the age of 10 months was unremarkable and patient's megalencephaly was described as familial benign megalencephaly. Kidney biopsy analysis showed characteristic signs of AS. Mutations screening with use of Illumina MiSeq platform revealed that the patient was homozygous for a newly discovered splice acceptor pathogenic variant c.193-2A>C found in COL4A4 at the genomic position chr2:227985866 and both parents were heterozygous carriers. The genetic heterogeneity of AS makes the diagnostic process challenging. Although renal biopsy provides information about the characteristic GBM changes and the degree of renal parenchyma damage (interstitial fibrosis and tubular atrophy ratio), genetic testing is a more sensitive and specific method that also gives insight into potential disease severity and clinical course, and provides the basis for genetic counseling.

Association of polymorphic variants in serotonin re-uptake transporter gene with Crohn's disease: a retrospective case-control study.

AIM: To analyze the distribution of SLC6A4 gene polymorphisms in Crohn's disease (CD) patients and their association with the disease. METHODS: We evaluated the presence/absence of promoter (5-HTTLPR, rs25531) and intron 2 (STin2 VNTR) polymorphic variants of SLC6A4 gene in a retrospective case-control study including 192 CD patients and 157 healthy controls (HC). Genotyping was performed by polymerase chain reaction. The association of polymorphisms with CD and its clinical subtypes was analyzed using χ2 and Fisher exact test, binary logistic regression, and haplotype analysis. RESULTS: CD patients and healthy controls had similar sex (88 [45.8%] vs 84 [53.5%] women, respectively; P=0.154) and age (41.3±12.8 years vs 41.7±8.8 years, respectively, P=0.091) distribution. Significant differences were observed in the STin2 genotype and allele distribution between CD patients and healthy controls (P=0.003 and P=0.002, respectively) and between the corresponding female subgroups (P=0.004 and P=0.007, respectively), with a significant negative association of biallelic ss (STin2.9 and Stin2.10) STin2 genotype with CD (P=0.013, age- and sex-adjusted odds ratio [OR] 0.5, 95% confidence interval [CI] 0.29-0.86; women: P=0.006, age-adjusted OR 0.32, 95% CI 0.14-0.72) and a significantly higher S-STin2.12 (5-HTTLPR/rs25531: S-STin2: STin2.12) haplotype distribution in CD patients (P=0.004, OR 1.62, 95% CI 1.16-2.26). There was no significant association between 5-HTTLRP and rs25531 genotype or allele frequencies and CD and between any SLC6A4 polymorphic loci with clinical CD subtypes. CONCLUSION: STin2 VNTR polymorphism of SLC6A4 gene may contribute to CD pathogenesis.

Biological characteristics and clinical management of uveal and conjunctival melanoma.

Uveal and conjunctival melanomas are relatively rare tumors; nonetheless, they pose a significant risk of mortality for a large number of affected individuals. The pathogenesis of melanoma at different sites is very similar, however, the prognosis for patients with ocular melanoma remains unfavourable, primarily due to its distinctive genetic profile and tumor microenvironment. Regardless of considerable advances in understanding the genetic characteristics and biological behaviour, the treatment of uveal and conjunctival melanoma remains a formidable challenge. To enhance the prospect of success, collaborative efforts involving medical professionals and researchers in the fields of ocular biology and oncology are essential. Current data show a lack of well-designed randomized clinical trials and limited benefits in current forms of treatment for these tumors. Despite advancements in the development of effective melanoma therapeutic strategies, all current treatments for uveal melanoma (UM) and conjunctival melanoma (CoM) remain unsatisfactory, resulting in a poor long-term prognosis. Ongoing trials offer hope for positive outcomes in advanced and metastatic tumors. A more comprehensive understanding of the genetic and molecular abnormalities involved in the development and progression of ocular melanomas opens the way for the development of personalized therapy, with various potential therapeutic targets currently under consideration. Increased comprehension of the molecular pathogenesis of UM and CoM and their specificities may aid in the development of new and more effective systemic therapeutic agents, with the hope of improving the prognosis for patients with metastatic disease.

Unraveling the Complexity of Childhood Polycystic Kidney Disease: A Case Study of Three Sisters.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disorder, estimated to affect 1 in 1000 people. It displays a high level of variability in terms of onset and severity among affected individuals within the same family. In this case study, three sisters (4, 8, and 10 years of age) were suspected of having ADPKD due to their positive family history. While the two younger sisters aged 8 and 4 showed no disease complications and had normal kidney function, the oldest sister was found to have no dipping status on ambulatory blood pressure measurement (ABPM). Two of the sisters were discovered to have a PKD1 mutation, while the third sister aged 8 was heterozygous for TTC21B c.1593_1595del, p. (Leu532del), which is a variant of uncertain significance (VUS). Environmental factors and genetic modifying factors are believed to contribute to the phenotypic variability observed in ADPKD. Identifying and understanding potential genetic and environmental modifiers of ADPKD could pave the way to targeted treatments for childhood ADPKD.

Clinical and histopathological characteristics of COL4A3 c.2881+1G>A variant causing Alport spectrum disorders in Croatian population.

Alport syndrome (AS) and thin basement membrane nephropathy (TBMN) are part of the spectrum of kidney disorders caused by pathogenic variants in α3, α4, or α5 chains of the collagen type IV, the major structural component of the glomerular basement membrane (GBM). Using targeted next-generation sequencing (NGS), 34 AS/TBMN patients (58.8% male) from 12 unrelated families were found positive for heterozygous c.2881+1G>A variant of the COL4A3gene, that is considered disease-causing. All patients were from the continental or island part of Croatia. Clinical, laboratory, and histopathological data collected from the medical records were analyzed and compared to understand the clinical course and prognosis of the affected patients. At the time of biopsy or first clinical evaluation, the mean age was 31 years (median: 35 years; range: 1 - 72 years). Hematuria was present in 33 patients (97.1%) and 19 (55.9%) patients had proteinuria. There were 6 (17.6%) patients with hearing loss, 4 (11.8%) with ocular lesions, and 11 (32.4%) with hypertension. Twenty-three (67.6%) patients had proteinuria at follow-up, and 5 (14.7%) patients with the median age of 48 years (range: 27-55) progressed to kidney failure, started dialysis, or underwent kidney transplantation. Of the 13 patients who underwent kidney biopsy, 4 (30.8%) developed focal segmental glomerulosclerosis (FSGS), and 8 (66.7%) showed lamellation of the GBM, including all patients with FSGS. It is essential to conduct a detailed analysis of each collagen type IV genetic variant to optimize the prognosis and therapeutic approach for affected patients.

Frequency of loss of heterozygosity of the NF2 gene in schwannomas from Croatian patients.

AIM: To identify gross deletions in the NF2 gene in a panel of schwannomas from Croatian patients in order to establish their frequencies in Croatian population. METHODS: Changes of the NF2 gene were tested by polymerase chain reaction/loss of heterozygosity (LOH) using two microsatellite markers, D22S444 and D22S929. RESULTS: The analysis with both markers demonstrated that 43.75% of schwannomas exhibited LOH of the NF2 gene. The D22S444 region exhibited 45.5% of LOHs and the D22S929 region exhibited 14.3% of LOHs. Four LOHs were found in Antoni B, 2 in Antoni A, and 1 in Antoni A and B type tumors. CONCLUSION: The frequency of changes observed in Croatian patients is broadly similar to that reported in other populations and thus confirms the existing hypothesis regarding the tumorigenesis of schwannomas and contributes to schwannoma genetic profile helping us to better understand its etiology and treatment.

Aberrant expression of SFRP1, SFRP3, DVL2 and DVL3 Wnt signaling pathway components in diffuse gastric carcinoma.

Diffuse gastric carcinoma (DGC) is characterized by poorly cohesive cells, highly invasive growth patterns, poor prognosis and resistance to the majority of available systemic therapeutic strategies. It has been previously reported that the Wnt/ß-catenin signaling pathway serves a prominent role in the tumorigenesis of gastric carcinoma. However, the mechanism underlying the dysregulation of this pathway in DGC has not been fully elucidated. Therefore, the present study aimed to investigate the expression profiles of Wnt antagonists, secreted frizzled-related protein 1 (SFRP1) and secreted frizzled-related protein 3 (SFRP3), and dishevelled protein family members, dishevelled segment polarity protein 2 (DVL2) and dishevelled segment polarity protein 3 (DVL3), in DGC tissues. The association between the expression levels of these factors and the clinicopathological parameters of the patients was determined. Protein and mRNA expression levels in 62 DGC tumor tissues and 62 normal gastric mucosal tissues obtained from patients with non-malignant disease were measured using immunohistochemical and reverse transcription-quantitative PCR (RT-qPCR) analysis. Significantly lower protein expression levels of SFRP1 (P<0.001) and SFRP3 (P<0.001), but significantly higher protein expression levels of DVL2 (P<0.001) and DVL3 (P<0.001) were observed in DGC tissues compared with in control tissues by immunohistochemistry. In addition, significantly lower expression levels of SFRP1 (P<0.05) and higher expression levels of DVL3 (P<0.05) were found in in DGC tissues compared with those in normal gastric mucosal tissues using RT-qPCR. According to correlation analysis between the SFRP1, SFRP3, DVL2 and DVL3 protein expression levels and the clinicopathological characteristics of patients with DGC, a statistically significant correlation was found between the SFRP3 volume density and T stage (r=0.304; P=0.017) and between the SFRP3 volume density and clinical stage (r=0.336; P=0.008). In conclusion, the findings of the present study suggested that the Wnt signaling pathway components SFRP1, SFRP3, DVL2 and DVL3 may be aberrantly expressed in DGC tissues, implicating their possible role in the development of this malignant disease. The present data also revealed a positive relationship between SFRP3 protein expression and the clinical and T stage of DGC.

Dishevelled family proteins in serous ovarian carcinomas: a clinicopathologic and molecular study.

Dishevelled family proteins (DVL1, DVL2, and DVL3) are cytoplasmic mediators involved in canonical and non-canonical Wnt signaling that are important for embryonic development. Since Wnt signaling promotes cell proliferation and invasion, its increased activation is associated with cancer development as well. To get deeper insight into the behavior of Dishevelled proteins in cancer, we studied their expression in serous ovarian carcinomas [both low- (LGSC) and high-grade (HGSC)], and HGSC cell lines OVCAR5, OVCAR8, and OVSAHO. DVL protein expression in serous ovarian carcinomas tissues was analyzed using immunohistochemistry, while DVL protein and mRNA expressions in HGSC cell lines were analyzed using Western blot and quantitative real-time PCR. DVL1 protein expression was significantly higher in LGSC compared with normal ovarian tissue, while DVL3 was overexpressed in both LGSC and HGSC. DVL2 and DVL3 protein expression was higher in HGSC cell lines when compared with normal control cell line FNE1, while DVL1, DVL2, and DVL3 mRNA expression was significantly increased only in OVSAHO cell line. Survival analysis revealed no significant impact of DVL proteins on patients' outcome. Our data show an active involvement of Dishevelled family proteins in serous ovarian carcinomas. Further studies should confirm the clinical relevance of these observations.

Negative regulators of Wnt signaling pathway SFRP1 and SFRP3 expression in preterm and term pathologic placentas.

OBJECTIVE: Since Wnt signaling pathway plays a pivotal role in the placental development, we explored the expression of its negative regulators, SFRP1 and SFRP3 proteins in placentas from pathological pregnancies and compared their levels with those in healthy placentas. METHODS: Placentas (n = 79) were stained for SFRP1, and SFRP3 proteins by immunohistochemistry and their expression levels were quantified by stereological variable of volume density (Vv, mm°). RESULTS: Significantly higher expressions of SFRP1 and SFRP3 were found in all investigated groups of term and preterm pathologic placentas as well as in preterm control placentas in comparison with normal-term placentas. CONCLUSIONS: Our findings indicate the active involvement of negative Wnt regulators SFRP1/SFRP3 in placental development and important role in pathology of pregnancy.

Genetic changes of CDH1, APC, and CTNNB1 found in human brain tumors.

This paper focuses on changes in E-cadherin (CDH1), adenomatous polyposis coli (APC), and beta-catenin (CTNNB1) in 50 tumors of the central nervous system. All gene products are components of adherens junctions, but are also involved in wnt signaling. The results of our analysis showed LOH of CDH1 gene in 31% of meningiomas examined (significant correlation; p=0.002). LOH was noted in a single case of germinoma, while other tumor types did not demonstrate any change in CDH1. Fourteen samples (29.2%) with changes in APC gene were observed. The changes were seen in 33.3% of glioblastomas and in 27% of meningiomas; LOH occurred in five informative astocytomas (20%) and in six informative neurinomas (17%). One oligoastrocytoma showed LOH at exon 11, and one medulloblastoma had allelic imbalance at both exons. Five samples (10%) showed heteroduplexes in exon 3 of beta-catenin. Potential mutations were confined to two meningiomas, one astrocytoma, one glioblastoma, and one germinoma. Our results suggest that genetic changes in wnt components are involved in brain tumor genesis. Changes in E-cadherin are involved in meningiomas, while changes in APC gene occur in different tumor types, with glioblastomas showing the highest percentage.

ELF5 transcription factor expression during gestation in humans and rats - an immunohistochemical analysis.

OBJECTIVE: The purpose of this study was to measure immunohistochemically the expression of ELF5 protein in term human and rat placentas and in human placentas associated with gestational diabetes (GD) and intrauterine growth restriction (IUGR). METHODS: The results were quantitated stereologically using the stereological variable of volume density. A semiquantitative analysis was performed independently by a certified pathologist. RESULTS: Total expression of ELF5 protein was higher in pathological pregnancies than in corresponding control term placentas, with both methods of quantifications showing similar results. In addition, ELF5 expression was also higher in connective tissue and blood vessels in chorionic villi in IUGR placentas (but not in GD placentas) compared to healthy controls. ELF5 is higher in placenta as a whole and in most of its components in both pathologies. The two exceptions are chorionic plates in IUGR and decidua in GD, where its expression is lower than in healthy controls. CONCLUSIONS: We have shown that IUGR and GD are associated with significantly increased levels of ELF5 protein in placentas, which suggests that ELF5 may play an important role in normal placentation. However, these are term placentas and to study ELF5 in premature births would give better insight into human placentation in health and disease.

Loss of heterozygosity of APC and CDH1 genes in laryngeal squamous cell carcinoma.

The molecular mechanisms involved in the development and progression of laryngeal cancer, specifically squamous cell carcinoma, still need further investigation and elucidation. Twenty-two laryngeal squamous cell carcinomas were analyzed in our study regarding genetic changes of two tumor suppressor genes: Adenomatous polyposis coli (APC) and E-cadherin (CDH1). APC gene instability was tested by polymerase chain reaction (PCR)/loss of heterozygosity (LOH) using the restriction fragment length polymorphism (RFLP) method. The samples were also screened for mutations using the heteroduplex method. E-cadherin gene was analyzed by PCR amplification of tetranucleotide marker (D16S752) linked to E-cadherin gene. The results of our analysis showed three samples with LOH of the APC gene out of 15 heterozygous patients (20%). Only one LOH of the CDH1 gene (5.5%) out of 18 heterozygous patients was discovered. D16S752 marker did not reveal any replication error-positive samples. There were six samples showing heteroduplexes (33%) encompassed in APC's exon 11. Altogether, nine samples (41%) showed alterations of the APC gene. Our results suggest that alterations of APC gene may have a role in squamous cell carcinoma development. Detected LOH of the E-cadherin gene indicates that genetic changes of this gene are not very frequent, but that other components of the wnt signaling cascade may also be involved.

Replication error-positive samples found in pheochromocytomas.

UNLABELLED: Adenomatous polyposis coli, (APC) and E-cadherin (CDH1) tumor suppressor genes were investigated in human pheochromocytoma. Both genes are components of adherens junctions, but are also involved in wnt signalling in which one of the target molecules is c-myc protein. MATERIALS AND METHODS: Fifteen sporadic pheochromocytomas were tested for gene instability by PCR/loss of heterozygosity. Detection of c-myc protein was performed using immunohistochemistry. RESULTS: One sample with allelic imbalance of the APC gene and one with allelic imbalance of the CDH1 gene were found. Interestingly, another type of genomic instability was detected--replication error-positive samples (RER+). Four out of 13 heterozygous samples were RER-positive (30.8%). The instability is the result of impaired cellular mismatch repair. Immunohistochemistry showed increased levels of c-myc in comparison to normal adrenal tissue. CONCLUSION: Our results suggest that microsatellite genetic instabilities of the E-cadherin gene have a role in pheochromocytoma development and progression. Detected instability indicates that mismatch repair may be targeted in pheochromocytoma. Increased expression of c-myc protein as well as allelic imbalances of APC and CDH 1 genes suggest that the wnt signalling pathway may have a role in this malignancy.

[New insights on genetics of malignant melanoma]. / Najnovije spoznaje o genskoj osnovi melanoma.

This review seeks to bring novel findings of genetic basis of melanoma. CDKN2A and CDK4 genes residing on chromosomes 9p21 and 12q14, as well as MC1R gene located at 16q24 are main candidates responsible for melanoma development and progression. These genes together with signal transduction pathways in which they are implied are primarily changed in hereditary melanoma. Moreover, changes of genes: BRAF, RAS, c-MET and PTEN characterize sporadic forms of melanoma. Today's knowledge on melanoma genetics is rather inconsistent and involves different genes and signalling pathways. Series of consecutive genetic events that lead to melanoma progression is a very dinamic scientific field in medicine.