Huseyin Onay

Vitiligo pathogenesis: autoimmune disease, genetic defect, excessive reactive oxygen species, calcium imbalance, or what else?

Abstract:  The pathobiology of vitiligo has been hotly disputed for as long as one remembers, and has been a magnet for endless speculation. Evidently, the different schools of thought – ranging, e.g. from the concept that vitiligo essentially is a free‐radical disorder to that of vitiligo being a primary autoimmune disease – imply very different consequences for the best therapeutic strategies that one should adopt. As a more effective therapy for this common, often disfiguring pigmentary disorder is direly needed, we must strive harder to settle the pathogenesis debate definitively – on the basis of sound experimental evidence, rather than by a war of dogmatic theories.

Testing the Psychosis Continuum: Differential Impact of Genetic and Nongenetic Risk Factors and Comorbid Psychopathology Across the Entire Spectrum of Psychosis

A growing number of studies demonstrate high rates of subthreshold psychotic experiences, but there is considerable heterogeneity in rates due to study cohort and design factors, obscuring how prevalent psychotic experiences may or may not relate to rare psychotic disorders. In a representative general population sample (n = 4011) in Izmir, Turkey, the full spectrum of expression of psychosis was categorized across 5 groups representing (1) absence of psychosis, (2) subclinical psychotic experiences, (3) low-impact psychotic symptoms, (4) high-impact psychotic symptoms, and (5) full-blown clinical psychotic disorder and analyzed for continuity and discontinuity in relation to (1) other symptom dimensions associated with psychotic disorder and (2) proxies of genetic and nongenetic etiology. Results were tested for linear and extralinear contrasts between clinical and nonclinical and between disorder and nondisorder expression of psychosis. Demographic variables, indexing premorbid social adjustment and socioeconomic status, impacted mostly linearly; proxy variables of genetic loading (more or more severely affected relatives) impacted in a positive extralinear fashion; environmental risk factors sometimes impacted linearly (urbanicity and childhood adversity) and sometimes extralinearly (cannabis), occasioning a disproportional shift in risk at the clinical disorder end of the spectrum. Affective symptoms were associated with a disproportionally higher risk below the disorder threshold, whereas a disproportionally higher risk above the threshold was associated with psychotic symptom load, negative symptoms, disorganization, and visible signs of mental illness. Liability associated with respectively affective and nonaffective symptom domains, in interaction with environmental risks, may operate by impacting differentially over a quasi-continuous extended psychosis phenotype in the population.

Mannose-binding lectin gene polymorphism and early neonatal outcome in preterm infants.

Background: Mannose-binding lectin (MBL) as a component of innate immunity plays an important role in preterm infants in whom adaptive immunity is not sufficiently developed. Polymorphisms in immunoregulatory genes influence the response to infection and subsequent inflammation. Infection and inflammation have been implicated in the mechanisms responsible for many of the diseases in the preterm newborns. Objectives: The aim of the study was to investigate the relationship between MBL gene polymorphism and early neonatal outcome in preterm infants. Methods: Codon 54 and 57 polymorphisms in MBL2 gene were genotyped in 99 preterm infants admitted to the Neonatal Intensive Care Unit at Ege University Children’s Hospital. Results: Overall frequencies of sepsis and early-onset sepsis were higher in the group of infants with MBL polymorphism when compared to infants with wild-type MBL genotype (p = 0.008, 0.009, respectively). Maximum Tollner sepsis score in the first 3 days of life was higher for the infants with variant MBL genotype (p = 0.0278). More infants in the variant MBL group had significant patent ductus arteriosus when compared to infants with wild-type MBL (27.8 vs. 9.5% respectively, p = 0.037). Conclusion: MBL gene polymorphism was associated with increased frequency of clinical sepsis particularly with early neonatal sepsis and also with higher Tollner sepsis scores and increased frequency of patent ductus arteriosus in infants. Overall mortality and incidence of culture proven sepsis, respiratory distress syndrome, bronchopulmonary dysplasia, intraventricular hemorrhage, periventricular leukomalacia and necrotizing enterocolitis were not found to be related to MBL genotype.

Association between IL4 (–590), ACE (I)/(D), CCR5 (Δ32), CTLA4 (+49) and IL1-RN (VNTR in intron 2) gene polymorphisms and vitiligo

Vitiligo is a common skin disorder characterized by patterned depigmentation, because of a decrease of melanin pigment resulting from apparent melanocyte loss. The aim of this study was to investigate interleukin 4 (IL4), Angiotensin Converting Enzyme (ACE), C-C Chemocine Receptor 5 (CCR5), Cytotoxic T Lymphocyte-associated Antigen Receptor 4 (CTLA4) and Interleukin 1 Receptor Antagonist (IL1-RN) gene polymorphisms in 48 Turkish vitiligo patients and 50 healthy controls. Polymorphisms for the genes ACE insertion(I)/deletion(D), CCR5 (Delta32), IL1-RN (VNTR in intron 2) were detected by PCR methods. IL4 (-590) and CTLA4 (+49) gene polymorphisms were typed using PCR-RFLP methods. No significant differences in either the genotype distribution or allele frequencies of IL4, CCR5 and ACE gene polymorphisms were observed. GG genotype and G allele in CTLA4 genes were found to be significantly higher in vitiligo patients compared to the controls. (0.002, 0.000). CTLA4 (AA) and IL1-RN (1/5) genotypes and 5 allele frequency in the IL1-RN gene were found to be significantly lower in vitiligo patients compared to healthy controls (p: 0.014, 0.015, 0.016, respectively). As a conclusion, CTLA4 and IL1-RN genes might play roles in the genetic etiology of vitiligo.

Assessment of Toll-like receptor-4 gene polymorphism on pyelonephritis and renal scar

The aim of this study was to evaluate the effect of the TLR‐4 gene TLR4 c.896A

Natural History of Congenital Generalized Lipodystrophy: A Nationwide Study From Turkey

CONTEXT Congenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by near-total lack of body fat. OBJECTIVE We aimed to study natural history and disease burden of various subtypes of CGL. DESIGN We attempted to ascertain nearly all patients with CGL in Turkey. SETTING This was a nationwide study. PATIENTS OR OTHER PARTICIPANTS Participants included 33 patients (22 families) with CGL and 30 healthy controls. MAIN OUTCOME MEASURE(S) We wanted to ascertain genotypes by sequencing of the known genes. Whole-body magnetic resonance imaging was used to investigate the extent of fat loss. Metabolic abnormalities and end-organ complications were measured on prospective follow-up. RESULTS Analysis of the AGPAT2 gene revealed four previously reported and four novel mutations (CGL1; c.144C>A, c.667_705delinsCTGCG, c.268delC, and c.316+1G>T). Analysis of the BSCL2 gene revealed four different homozygous and one compound heterozygous possible disease-causing mutations (CGL2), including four novel mutations (c.280C>T, c.631delG, c.62A>T, and c.465-468delGACT). Two homozygous PTRF mutations (c.481-482insGTGA and c.259C>T) were identified (CGL4). Patients with CGL1 had preservation of adipose tissue in the palms, soles, scalp, and orbital region, and had relatively lower serum adiponectin levels as compared to CGL2 patients. CGL4 patients had myopathy and other distinct clinical features. All patients developed various metabolic abnormalities associated with insulin resistance. Hepatic involvement was more severe in CGL2. End-organ complications were observed at young ages. Two patients died at age 62 years from cardiovascular events. CONCLUSIONS CGL patients from Turkey had both previously reported and novel mutations of the AGPAT2, BSCL2, and PTRF genes. Our study highlights the early onset of severe metabolic abnormalities and increased risk of end-organ complications in patients with CGL.

Comprehensive Analysis of Deafness Genes in Families with Autosomal Recessive Nonsyndromic Hearing Loss.

Comprehensive genetic testing has the potential to become the standard of care for individuals with hearing loss. In this study, we investigated the genetic etiology of autosomal recessive nonsyndromic hearing loss (ARNSHL) in a Turkish cohort including individuals with cochlear implant, who had a pedigree suggestive of an autosomal recessive inheritance. A workflow including prescreening of GJB2 and a targeted next generation sequencing panel (Illumına TruSightTM Exome) covering 2761 genes that we briefly called as mendelian exome sequencing was used. This panel includes 102 deafness genes and a number of genes causing Mendelian disorders. Using this approach, we identified causative variants in 21 of 29 families. Three different GJB2 variants were present in seven families. Remaining 14 families had 15 different variants in other known NSHL genes (MYO7A, MYO15A, MARVELD2, TMIE, DFNB31, LOXHD1, GPSM2, TMC1, USH1G, CDH23). Of these variants, eight are novel. Mutation detection rate of our workflow is 72.4%, confirming the usefulness of targeted sequencing approach in NSHL.

Evidence that the wider social environment moderates the association between familial liability and psychosis spectrum outcome.

BACKGROUND Familial liability to both severe and common mental disorder predicts psychotic disorder and psychotic symptoms, and may be used as a proxy in models examining interaction between genetic risk and the environment at individual and contextual levels. METHOD In a representative general population sample (n=4011) in Izmir, Turkey, the full spectrum of expression of psychosis representing (0) no symptoms, (1) subclinical psychotic experiences, (2) low-impact psychotic symptoms, (3) high-impact psychotic symptoms and (4) full-blown clinical psychotic disorder was assessed in relation to mental health problems in the family (proxy for familial liability) and the wider social environment. Quality of the wider social environment was assessed in an independent sample using contextual measures of informal social control, social disorganization, unemployment and low income, aggregated to the neighbourhood level. RESULTS The association between familial liability to severe mental illness and expression of psychosis spectrum was stronger in more deprived neighbourhoods [e.g. this association increased from β=0.33 (p=0.01) in low-unemployment neighbourhoods to β=0.92 (p<0.001) in high-unemployment neighbourhoods] and in neighbourhoods high in social control, while neighbourhood variables did not modify the association between familial liability to common mental disorder and the psychosis outcome. Neighbourhood variables mediated urbanicity effects. CONCLUSIONS Contextual effects may be important in moderating the expression of psychosis liability in populations, representing a specific pathway independent of the link between common mental disorder and psychosis.

Multigene Methylation Analysis of Conventional Renal Cell Carcinoma

Renal cell carcinoma (RCC) is the most common malignancy of the kidney. Since RCC is curable when it is confined to the renal capsule, early diagnosis is extremely important. Promoter hypermethylation is the most common mechanism for the inactivation of the tumor suppressor genes (TSG) in the development of human cancer. This study aimed to investigate the methylation profiles of 7 TSG (RASSF1A, ECAD, TIMP3, APC, MGMT, p16 and RARβ2) in 3 different tissue samples (normal, premalign, malign) of patients with RCC. Twenty-one patients diagnosed with RCC were included in the study. Methylation-specific polymerase chain reaction was performed to detect the methylation patterns of the 7 TSG. High methylation rates for the genes RASSF1A (76%), p16 (80%), ECAD (42%), TIMP3 (33%) and MGMT (33%) were observed in the patients with RCC. The APC (14%) and RARβ2 (19%) genes showed low methylation rates. In conclusion, 5 TSG (RASSF1A, ECAD, TIMP3, MGMT and p16) showed high methylation rates in RCC patients. A methylation-based gene test including these genes may be useful in the early detection of RCC.

A Severe α Thalassemia Case Compound Heterozygous for Hb Adana in α1 Gene and 20.5 kb Double Gene Deletion

We report a 6-year-old boy diagnosed as transfusion dependent chronic nonspherocytic hemolytic anemia since 40 days old. Hemoglobin H inclusions were detected with brilliant cresyl blue preparation. His parents were found to be normal on physical examination. His mother had hemoglobin level of 9.34 g/dL, accompanied by typical thalassemic changes of the red cells, and inclusion bodies were also detected with brilliant cresyl blue staining. His father had normal hemoglobin level and borderline red cell indices. Mutation analysis using strip assay capable of detecting 22 mutations within the alpha genes was performed for the proband and the parents which revealed that the case was compound heterozygous for Hb Adana in alpha1 gene and 20.5 kb double gene deletion. The father was found to be heterozygous for Hb Adana alpha1 gene whereas the mother was found to be compound heterozygous for 20.5 kb double gene deletion and 3.7 kb single gene deletion. It is well known that non deletional forms of HbH disease are more severe than the deletional forms. This case represents another example of the nondeletional mutation underlying Hb Adana, which is rarely seen in alpha1 gene, and illustrates the distinctive phenotypes of both the deletional and nondeletional forms of hemoglobin H disease within the same family.