Search For Susceptibility Genes In Schizophrenia

Schizophrenia is a severe mental disorder affecting 0.4-1% of the population worldwide. It is characterized by impairments in the perception of reality and by significant social or occupational dysfunction. The disorder is one of the major contributors to the global burden of diseases. Studies of twins, families, and adopted children point to strong genetic components for schizophrenia, but environmental factors also play a role in the pathogenesis of disease. Molecular genetic studies have identified several potential positional candidate genes. The strongest evidence for putative schizophrenia susceptibility loci relates to the genes encoding dysbindin (DTNBP1) and neuregulin (NRG1), but studies lack impressive consistency in the precise genetic regions and alleles implicated. We have studied the role of three potential candidate genes by genotyping 28 single nucleotide polymorphisms in the DNTBP1, NRG1, and AKT1 genes in a large schizophrenia family sample consisting of 441 families with 865 affected individuals from Finland. Our results do not support a major role for these genes in the pathogenesis of schizophrenia in Finland. We have previously identified a region on chromosome 5q21-34 as a susceptibility locus for schizophrenia in a Finnish family sample. Recently, two studies reported association between the γ-aminobutyric acid type A receptor cluster of genes in this region and one study showed suggestive evidence for association with another regional gene encoding clathrin interactor 1 (CLINT1, also called Epsin 4 and ENTH). To further address the significance of these genes under the linkage peak in the Finnish families, we genotyped SNPs of these genes, and observed statistically significant association of variants between GABRG2 and schizophrenia. Furthermore, these variants also seem to affect the functioning of the working memory. Fetal events and obstetric complications are associated with schizophrenia. Rh incompatibility has been implicated as a risk factor for schizophrenia in several epidemiological studies. We conducted a family-based candidate-gene study that assessed the role of maternal-fetal genotype incompatibility at the RhD locus in schizophrenia. There was significant evidence for an RhD maternal-fetal genotype incompatibility, and the risk ratio was estimated at 2.3. This is the first candidate-gene study to explicitly test for and provide evidence of a maternal-fetal genotype incompatibility mechanism in schizophrenia. In conclusion, in this thesis we found evidence that one GABA receptor subunit, GABRG2, is significantly associated with schizophrenia. Furthermore, it also seems to affect to the functioning of the working memory. In addition, an RhD maternal-fetal genotype incompatibility increases the risk of schizophrenia by two-fold.Skitsofrenia on vakava mielenterveyden häiriö ja sitä esiintyy noin 0,4-1 % maailman väestöstä. Skitsofreniaa sairastavilla on ongelmia todellisuuden havainnoinnissa ja heidän sosiaalinen toimintansa on yleensä häiriintynyt. Perhe-, kaksos- ja adoptiotutkimusten perusteella skitsofrenialla on merkittävä perinnöllinen tausta, mutta myös ympäristötekijätkin vaikuttavat taudin syntyyn. Olemme aikaisemmin löytäneet kromosomista 5 alueen, joka kytkeytyi skitsofreniaan perhemateriaalissamme. Aineistomme koostui 441 perheestä käsittäen 865 skitsofreniaa sairastavaa ihmistä. Viime aikoina on tältä samalta alueelta löydetty muissa väestöissä useita geenejä, joiden variaatiot näyttäisivät altistavan skitsofrenialle. Erityisesti hermoston välittäjäaineen γ-aminovoihappo A-tyypin reseptoreiden alayksiköistä muodostuva geenirykelmä näyttäisi liittyvän suurentuneeseen riskiin sairastua tautiin. Halusimme tutkia näiden geenien roolia skitsofreniassa myös suomalaisessa väestössä analysoimalla niissä sijaisevia variaatioita. Havaitsimme, että GABRG2 geenin variaatiot näyttäisivät liittyvän skitsofrenian sairastumisriskiin. Lisäksi nämä variaatiot näyttivät liittyvän myös työmuistin toimintaan. Skitsofreniaa sairastavien kongnitiiviset toiminnot ovat usein huonontuneet, joten löydös voi tulevaisuudessa avata uusia mahdollisuuksia työmuistin toiminnan tutkimuksessa. Viime aikaiset molkyyligeneettiset tutkimukset maailmalla ovat löytäneet useita lupaavia skitsofrenialle altistavia ehdokasgeenejä, mutta eri väestöistä saadut tulokset eivät ole yksiselitteisiä. Kaksi ehkä vahvinta ehdokasta ovat dysbindin (DTNBP1) ja neureguliini (NRG1). Tutkimme näiden sekä AKT1-geenin roolia suomalaisessa perhemateriaalissamme analysoimalla 28 yhden nukelotidin muutosta (SNP, single nucelotide polymorphism). Tulostemme valossa näiden kolmen geenin variaatiot eivät ole merkittäviä riskitekijöitä skitsofrenialle meidän väestössämme. Raskauden aikaiset komplikaatiot lisäävät sikiön riskiä sairastua skitsofreniaan noin kaksinkertaiseksi myöhemmin elämässä. Rhesus -veriryhmän yhteenopimattomuus on epidemiologisissa tutkimuksissa yhdistetty skitsofreniaan. Tämän veriryhmän yhteensopimattomuus voi vakavammillaan johtaa sikiölle vaaralliseen hemolyyttiseen tautiin. Tutkimme tätä äidin ja sikiön RhD-geenin yhteensopimattomuutta skitsofrenia perheaineistossamme. RhD-geenin yhteensopimattomuus äidin ja sikiön välillä nosti sikiön sairastumisriskiä 2,26-kertaiseksi meidän. Tämä on maailmassa ensimmäin tutkimus, joka suoraan pystyi yhdistämään äidin ja sikiön yhteensopimattomuuden geenitasolla skitsofreniaan. On kuitenkin humioitava, että tutkimukseen osallistuneet henkilöt olivat syntyneet suurimmaksi osaksi ennen 70-lukua, joten anti-D-vasta-aineiden anto äidille ei ollut vakiintunut käytäntö Suomessa. RhD geenin yhteensopimattomuuden roolia skitsofrenialle altistavana tekijänä myöhemmin syntyneiden joukossa ei tiedetä. Tässä väitöskirjassa löysimme viitteitä, että yhden GABA välittäjäainereseptorin (GABRG2) variaatiot perimässä altistavat skitsofrenialle. Osoitimme myös, että RhD veriryhmän yhteensopimattomuus äidin ja sikiön välillä näyttäisi lisäävän sikiön riskiä sairastua myöhemmin skitsofrenialle

Effect of Rhesus D incompatibility on schizophrenia depends on offspring sex.

Rhesus D incompatibility increases risk for schizophrenia, with some evidence that risk is limited to male offspring. The purpose of this study is to determine whether risk for schizophrenia due to Rhesus D incompatibility differs by offspring sex using a nuclear family-based candidate gene approach and a meta-analysis approach. The genetic study is based on a sample of 277 nuclear families with RHD genotype data on at least one parent and at least one child diagnosed with schizophrenia or related disorder. Meta-analysis inclusion criteria were (1) well-defined sample of schizophrenia patients with majority born before 1970, (2) Rhesus D incompatibility phenotype or genotype data available on mother and offspring, and by offspring sex. Two of ten studies, plus the current genetic study sample, fulfilled these criteria, for a total of 358 affected males and 226 affected females. The genetic study found that schizophrenia risk for incompatible males was significantly greater than for compatible offspring (p=0.03), while risk for incompatible and compatible females was not significantly different (p=.32). Relative risks for incompatible males and females were not significantly different from each other. Meta-analysis using a larger number of affected males and females supports their difference. Taken together, these results provide further support that risk of schizophrenia due to Rhesus D incompatibility is limited to incompatible males, although a weak female incompatibility effect cannot be excluded. Sex differences during fetal neurodevelopment should be investigated to fully elucidate the etiology of schizophrenia

BAP1 germline variants in Finnish patients with malignant mesothelioma

Objectives: Although asbestos exposure is the most common cause of malignant mesothelioma (MM), an aggressive cancer of the pleura or peritoneum, up to 7% of patients harbor a genetic predisposition to MM. Pathogenic germline variants in the BRCA1-associated protein 1 (BAP1) gene cause a dominantly inherited tumor predisposition syndrome, BAP1-TPDS, in which MM is the second most common associated cancer. Other frequent cancers in BAP1-TPDS are uveal melanoma (UM), cutaneous melanoma and renal cell carcinoma. Additionally patients can exhibit benign skin lesions, BAP1-inactivated nevi (BIN). Most BINs arise sporadically, but patients with BAP1-TPDS may harbor multiple BINs before other tumors or as the only indication of the syndrome. Our objective was to establish the frequency of pathogenic germline BAP1 variants in Finnish patients with MM. Materials and methods: 56 DNA samples archived in the Helsinki Biobank from Finnish patients with MM were sequenced for germline BAP1 variations. Formalin fixed paraffin embedded nevi from a pathogenic variant carrier were subjected to immunohistochemistry and exome sequencing. Results: Sanger sequencing identified one patient with Finnish founder mutation c.1780_1781insT, p. (G549Vfs*49) in BAP1. The carrier was diagnosed with MM over fifteen years before the cohorts mean onset age (mean 68, range 27 to 82) although the patient had no asbestos exposure or family history of BAP1-TPDS. However, the patient had three BINs removed prior to the MM. The c.1780_1781insT is now found from five Finnish BAP1-TPDS families with unknown common ancestor. Conclusion: The frequency of pathogenic germline BAP1 variants in Finnish patients with MM is 1.8 % (95 % CI, 0.04 to 9.2), comparable to the frequency in Finnish patients with UM (1.9 %). The frequency of recurring BINs in patients with BAP1-TPDS should be studied further and genetic testing for BAP1 variants considered if the patient has >= 2 BAP1-TPDS core tumors, including BINs.Peer reviewe

Clinical Spectrum and Geographic Distribution of Keratitis Fugax Hereditaria Caused by the Pathogenic Variant c.61G>C in NLRP3

Publisher Copyright: © 2021 The Author(s)PURPOSE: To chart clinical findings in individuals with keratitis fugax hereditaria (KFH) and the geographic distribution of their ancestors. DESIGN: A prospective cross-sectional study. METHODS: This study took place in a tertiary referral center with a cohort of 84 Finnish patients (55% female) from 25 families with the pathogenic nucleotide-binding domain, leucine-rich repeat (NLR) family pyrin domain containing 3 (NLRP3) variant c.61G>C. Observation procedures and main outcome measures were Sanger sequencing, clinical examination, corneal imaging, and a questionnaire regarding symptoms, quality of life, treatment, and comorbidities. RESULTS: The oldest members in each family were born in Ostrobothnia in Western Finland or in Southwestern Finland with historical ties to Sweden. One carrier was asymptomatic. Most (77%, 46/60) experienced their first attack between age 6 and 20 years. Three-quarters had unilateral attacks 3 to 5 times annually, primarily triggered by cold wind or air, or stress. Eighty percent (48/60) reported ocular pain (median, 7 on scale 1-10), conjunctival injection, photophobia, foreign body sensation, and tearing during attacks. Visual blur occurred in 75% (45/60) and 91% (55/60) during and after the attack, respectively, for a median of 10 days (range, 1 day-2 months). Forty-seven percent (39/60) had corneal oval opacities with irregular tomography patterns and mild to moderate decrease (20/60 or better) in best-corrected visual acuity that improved with scleral contact lenses. Except for headache in 40%, systemic symptoms were absent during the attacks. CONCLUSIONS: Symptoms and signs of KFH are restricted to the anterior segment of the eye and vary widely between individuals. We recommend scleral contact lenses as the first-line treatment for reduced vision. Allele frequencies suggest that KFH goes unrecognized in Sweden and populations with Scandinavian heritage.Peer reviewe

Natural history and biomarkers of retinal dystrophy caused by the biallelic TULP1 variant c.148delG

Purpose To report clinical features and potential disease markers of inherited retinal dystrophy (IRD) caused by the biallelic c.148delG variant in the tubby-like protein 1 (TULP1) gene. Methods A retrospective observational study of 16 IRD patients carrying a homozygous pathogenic TULP1 c.148delG variant. Clinical data including fundus spectral-domain optical coherence tomography (SD-OCT) were assessed. A meta-analysis of visual acuity of previously reported other pathogenic TULP1 variants was performed for reference. Results The biallelic TULP1 variant c.148delG was associated with infantile and early childhood onset IRD. Retinal ophthalmoscopy was primarily normal converting to peripheral pigmentary retinopathy and maculopathy characterized by progressive extra-foveal loss of the ellipsoid zone (EZ), the outer plexiform layer (OPL), and the outer nuclear layer (ONL) bands in the SD-OCT images. The horizontal width of the foveal EZ showed significant regression with the best-corrected visual acuity (BCVA) of the eye (p < 0.0001, R-2 = 0.541, F = 26.0), the age of the patient (p < 0.0001, R-2 = 0.433, F = 16.8), and mild correlation with the foveal OPL-ONL thickness (p = 0.014, R-2 = 0.245, F = 7.2). Modelling of the BCVA data suggested a mean annual loss of logMAR 0.027. The level of visual loss was similar to that previously reported in patients carrying other truncating TULP1 variants. Conclusions This study describes the progression of TULP1 IRD suggesting a potential time window for therapeutic interventions. The width of the foveal EZ and the thickness of the foveal OPL-ONL layers could serve as biomarkers of the disease stage.Peer reviewe

Association of the MYOC p.(Gln368Ter) Variant With Glaucoma in a Finnish Population

IMPORTANCE The c.1102C>T, p.(Gln368Ter) variant in themyocilin (MYOC) gene is a known risk allele for glaucoma. It is the most common MYOC risk variant for glaucoma among individuals of European ancestry, and its prevalence is highest in Finland. Furthermore, exfoliation syndrome has high prevalence in Scandinavia, making the Finnish population ideal to study the association of the variant with different types of glaucoma. OBJECTIVES To examine the association and penetrance of MYOC p.(Gln368Ter) (rs74315329) variant with different types of glaucoma in a Finnish population. DESIGN, SETTING, AND PARTICIPANTS This genetic association study included individuals of Finnish ancestry in the FinnGen project. The participants were collected from Finnish biobanks, and the disease end points were defined using nationwide registries. The MYOC c.1102C>T variant was either directly genotyped or imputed with microarrays. Recruitment of samples to FinnGen was initiated in 2017, and data analysis was performed between December 2019 and May 2020. MAIN OUTCOMES AND MEASURES The main outcomes were odds ratios (ORs) and penetrance with different types of glaucoma and in different age groups. RESULTS A total of 218 792 individuals were included in this study (mean [SD] age 52.4 [17.5] years; 123 579 women [56.5%]), including 8591 (3.9%) with glaucoma, 3412 (1.6%) with primary open-angle glaucoma, 1515 (0.7%) with exfoliation glaucoma, 892 (0.4%) with normal-tension glaucoma, and 4766 (2.2%) with suspected glaucoma. The minor allele frequency of MYOC p.(Gln368Ter) was 0.28%. Individuals with the heterozygous variant had higher odds of primary open-angle glaucoma (OR, 3.36; 95% CI, 2.55-4.37), overall glaucoma (OR, 2.58; 95% CI, 2.12-3.13), suspected glaucoma (OR, 2.53; 95% CI, 1.93-3.26), exfoliation glaucoma (OR, 2.61; 95% CI, 1.60-4.02), and undergoing glaucoma-related operations (OR, 5.45; 95% CI, 2.95-9.28). The penetrance of heterozygous MYOC p.(Gln368Ter) was 5.2% in individuals with primary open-angle glaucoma, 9.6% in individuals with glaucoma, 5.4% in individuals with suspected glaucoma, and 1.9% in individuals with exfoliation glaucoma. There was no significant association with normal-tension glaucoma (OR, 1.69; 95% CI, 0.72-3.35). CONCLUSIONS AND RELEVANCE This genetic association study found that the MYOC p.(Gln368Ter) variant was associated with exfoliation glaucoma. The association with normal-tension glaucoma could not be replicated. These findings suggest that MYOC p.(Gln368Ter) was associated with open-angle glaucoma and exfoliation glaucoma in a Finnish population.Peer reviewe

Keratoendotheliitis Fugax Hereditaria : A Novel Cryopyrin-Associated Periodic Syndrome Caused by a Mutation in the Nucleotide-Binding Domain, Leucine-Rich Repeat Family, Pyrin Domain-Containing 3 (NLRP3) Gene

PURPOSE: To describe the phenotype and the genetic defect in keratoendotheliitis fugax hereditaria, an autosomal dominant keratitis that periodically affects the corneal endothelium and stroma, leading in some patients to opacities and decreased visual acuity. DESIGN: Cross-sectional, hospital-based study. METHODS: PATIENT POPULATION: Thirty affected and 7 unaffected subjects from 7 families, and 4 sporadic patients from Finland. OBSERVATION PROCEDURES: Ophthalmic examination and photography, corneal topography, specular microscopy, and optical coherence tomography in 34 patients, whole exome sequencing in 10 patients, and Sanger sequencing in 34 patients. MAIN OUTCOME MEASURES: Clinical phenotype, disease causing genetic variants. RESULTS: Unilateral attacks of keratoendotheliitis typically occurred 1-6 times a year (median, 2.5), starting at a median age of 11 years (range, 5-28 years), and lasted for 1-2 days. The attacks were characterized by cornea pseudoguttata and haze in the posterior corneal stroma, sometimes with a mild anterior chamber reaction, and got milder and less frequent in middle age. Seventeen (50%) patients had bilateral stroma! opacities. The disease was inherited as an autosomal dominant trait. A likely pathogenic variant c.61G > C in the NLRP3 gene, encoding cryopyrin, was detected in all 34 tested patients and segregated with the disease. This variant is present in both Finnish and non-Finnish European populations at a frequency of about 0.02% and 0.01%, respectively. CONCLUSION: Keratoendotheliitis fugax hereditaria is an autoinflammatory cryopyrin-associated periodic syndrome caused by a missense mutation c.61G > C in exon 1 of NLRP3 in Finnish patients. It is additionally expected to occur in other populations of European descent. ((c) 2018 The Author(s). Published by Elsevier Inc.Peer reviewe