Grażyna Kostrzewa

M34T and V37I mutations in GJB2 associated hearing impairment: Evidence for pathogenicity and reduced penetrance

Despite research the role of the M34T and V37I variants of GJB2 in causing hearing impairment (HI) remains controversial. Our purpose was to test a hypothesis that M34T and V37I are pathogenic but have distinct features resulting in a reduced penetrance. We screened for known GJB2/GJB6 mutations 233 Polish consecutive unrelated subjects with non‐syndromic, sensorineural HI who were previously found to carry 35delG mutation on one chromosome. The most frequent mutations were also analyzed in ∼1,000 controls. We found that M34T and V37I were significantly (P ≪ 10−6) overrepresented among patients, but their penetrance was estimated as 1/10 relative to mutations of undisputed pathogenicity. This finding apparently could not be explained by low degree of HI associated with M34T and V37I since another mutation causing comparably mild HI (L90P) did not have reduced penetrance. Subsequent analyses showed that the patients with M34T/35delG and V37I/35delG had significantly later onset of HI than patients with other genotypes (P < 10−6) including the L90P/35delG (P = 0.006). Also, among these patients (but not others) a strong correlation between the degree of HI and its duration was found (r = 0.79, P < 10−5). We tentatively suggest that M34T and V37I might cause mild HI characterized by relatively late onset and progression.

Molecular background of polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome in a Polish population: novel AIRE mutations and an estimate of disease prevalence.

Autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy (APECED) is an autosomal‐recessive autoimmune disease caused by autoimmune regulator gene mutations. The aim of this study was to examine the mutation profile of Polish APECED patients, determine the carrier rate of the most frequent mutation(s) and estimate disease prevalence. While studying 14 unrelated patients, we identified three novel mutations (c.1A>T, affecting the start codon; [IVS1 + 1G>C; IVS1 + 5delG], a complex mutation affecting splice site; c. 908G>C, p.R303P, a missense mutation in plant homeodomain (PHD) and three previously reported mutations (c.769C>T, p.R257X; c.967_979del13bp, C322fsX372; c.931delT, p.C311fsX376). Eleven patients had mutations on both chromosomes, whereas in three patients only a single alteration with proven or likely pathogenic effect was detected. The most frequent was the p.R257X mutation (71% of chromosomes); its carriage rate was assessed in the background population. Analysis of 2008 samples showed eight heterozygotes, indicating the frequency of 0.40% (1:250) and the disease prevalence – 1:129,000 (95% confidence interval: 1:555,000 to 1:30,000). Comparison with an epidemiological estimate (1:619,000, derived for women) suggested that in Poland, APECED is underdiagnosed. Among the patients, no genotype/phenotype correlations were found, but we noted that women had earlier onset of hypoparathyroidism (p < 0.02) and were younger at diagnosis (p < 0.05) than men.

Filaggrin Gene Defects Are Independent Risk Factors for Atopic Asthma in a Polish Population: A Study in ECAP Cohort

Background FLG null variants of which 2282del4 and R501X are the most frequent in Caucasians are established risk factors for atopic dermatitis (AD) with an effect probably mediated through impairment of epidermal barrier. Among subjects with AD FLG defects are also consistently associated with asthma and allergic rhinitis (AR) but it is less clear to what extent these associations are also present independently from skin disease. The aim of the present study was to evaluate the role of 2282del4 and R501X in predisposing to these allergic phenotypes in a Polish population. Methodology 2282del4 and R501X were typed among 3,802 participants of the Epidemiology of Allergic Diseases in Poland (ECAP) survey, a cross-sectional population-based study using ECRHS II and ISAAC questionnaires, and ambulatory examination. Principal Findings The FLG null variants were associated with AD (OR = 2.01, CI: 1.20–3.36, P = 0.007), allergic rhinitis (in particular persistent form, OR = 1.69, CI:1.12–2.54, P = 0.011), and asthma (in particular atopic asthma, OR = 2.22, CI:1.24–3.96, P = 0.006). Association with atopic asthma (but not persistent allergic rhinitis) was also present in the absence of AD, (OR = 2.02, CI: 1.07–3.81, P = 0.027) as well as in the absence of AD and history of broadly defined inflammatory skin disease (OR = 2.30, CI: 1.07–4.93, P = 0.03). Association to atopic asthma would have not been found if diagnosis was made by questionnaire only (OR = 1.15, CI: 0.58–2.32, P = 0.8). We did not observe an association between FLG variants and allergic sensitizations (P = 0.8) or total IgE. (P = 0.6). Conclusions/Significance In a Polish population FLG 2282del4 and R501X carriage increases risk for development of AD and atopic asthma (also in the absence of AD or history thereof). This suggests that interventions aimed at restoring epidermal barrier may have a general role in asthma prophylaxis/treatment.

Cytochrome P450 2C19 polymorphism, suboptimal reperfusion and all-cause mortality in patients with acute myocardial infarction.

Objectives: To determine whether the 681 G>A (*2) polymorphism of cytochrome P450 (CYP2C19) is related to suboptimal reperfusion and mortality in patients with acute myocardial infarction (AMI) pretreated with clopidogrel. Methods: Thestudy included 276 consecutive patients with AMI in whom percutaneous coronary intervention (PCI) with stenting was attempted. Four-year follow-up for all-cause mortality was obtained. Results: There were 15 failed procedures (5.4%). In the remaining 261 patients, suboptimal reperfusion (post-PCI TIMI flow <3) was observed in 12.6% of the cases. There were 56 carriers (50 heterozygous and 6 homozygous) of CYP2C19*2. The prevalence of carriers in patients with suboptimal flow was 39.4% in comparison to 18.9% in the other patients (p = 0.01). Independent predictors of suboptimal reperfusion were initial TIMI flow ≤1 (OR = 5.9, 95% CI 2.2–16.2, p = 0.001) and CYP2C19*2 (OR = 2.9, 95% CI 1.3–6.6, p = 0.01). Thirty patients died during follow-up (11.5%). Four-year mortality tended to be higher in carriers of CYP2C19*2 (17.9%) versus non-carriers (9.8%; p = 0.09), but the only independent predictors of death were age (HR = 2.0, 95% CI = 1.4–2.8, p = 0.0001) and suboptimal reperfusion (HR = 3.6, 95% CI 1.5–8.8, p = 0.004). Conclusions: The CYP2C19*2 allele is an independent predictor of suboptimal reperfusion in patients with AMI undergoing PCI with stenting after pretreatment with clopidogrel and may increase the risk of all-cause mortality.

Effect of protein convertase subtilisin/kexin type 9 (PCSK9) 46L gene polymorphism on LDL cholesterol concentration in a Polish adult population

The purpose was to study the effect of PCSK9 46L on cholesterol concentration and cardiovascular morbidity. By comparing 176 carriers with 6618 non-carriers identified through a cross-sectional population study (WOBASZ) we confirmed the LDL lowering effect of PCSK9 46L and demonstrated that it increases with the concentration of LDL. We noted that PCSK9 46L was associated with tendency for protection from myocardial infarction but not stroke suggesting a difference in the effect on susceptibility to these disorders.

Polymorphism of the oestrogen receptor beta gene (ESR2) is associated with susceptibility to Graves' disease.

Objective  To investigate whether a polymorphism in the ESR2 gene (rs4986938, previously associated with endometriosis, ovulatory dysfunction and premature onset of coronary heart disease) increases the risk of Graves’ disease (GD).

PTPN22/LYP 1858C>T gene polymorphism and susceptibility to endometriosis in a Polish population.

Endometriosis is a common gynaecological disorder due to ectopic implantation of endometrial tissue. It is manifested by pelvic inflammation and abrogation of cell-mediated immunity and may be also characterised by autoantibody production, thus suggesting that endometriosis might be an autoimmune disorder. Genetic factors also play a role in the aetiopathogenesis of this disease. Therefore, the present study was aimed at testing the association of endometriosis with the PTPN22/LYP 1858C> T gene polymorphism, which appears to be related to the development of a variety of autoimmune disorders. The study included 171 Polish patients of Caucasian origin with laparoscopically and histopathologically confirmed endometriosis and 310 unrelated, ethnically matched control individuals. DNA and serum were isolated from the peripheral blood. The PTPN22/LYP 1858C> T polymorphism was typed using a PCR-RFLP method. Anti-nuclear (ANA) and anti-cardiolipin (ACA) autoantibodies were detected by the Hep-2 indirect immunofluorescence test and a specific ELISA respectively. No statistically significant differences were found in distribution of C and T PTPN22/LYP alleles and genotypes in patients with endometriosis compared with the control population. However, on exploratory analyses we noted that the PTPN22/LYB T allele and the TT genotype may be associated with the prevalence of double positivity for ANA and ACA (p=0.003 by chi(2) test for trend and p=0.009 by Fishers exact test respectively). The results of the present study show that endometriosis in a Polish population is not associated with the PTPN22/LYP 1858C> T gene polymorphism. The putative effect of the PTPN22/LYP genotype on the development of autoantibodies is potentially interesting, but it should be verified in further studies.

Association between Tryptophan Hydroxylase 2 Gene Polymorphism and Completed Suicide

The association between suicide and a single nucleotide polymorphism (rs1386483) was examined in the recently identified tryptophan hydroxylase 2 (TPH2) gene. Blood samples of 143 suicide victims and 162 age- and sex-matched controls were examined. The frequency of the TT genotype in the TPH2 polymorphism was higher in suicide victims than in controls (17.5% vs. 8.6%; p = 0.02), particularly in those with a history of repeated suicide attempts (53.3% vs. 8.6%; p < 0.0001). The examined TPH2 polymorphism was found to be associated with suicide. This genetic marker may be particularly important in understanding risk of multiple suicide attempts. Further analyses are needed to confirm these results.

Angiotensin-Converting Enzyme Polymorphism and Completed Suicide: An Association in Caucasians and Evidence for a Link with a Method of Self-Injury

Background/Aims: An association between the II genotype of the angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism and suicide was found among Japanese men. Our purpose was to replicate this finding in Caucasians and explore other putative genotypic associations among suicides. Methods: The ACE genotypes were studied by a 2-stage PCR method in 150 completed suicides and 165 age- and sex-matched controls. Results: We found an increase in the frequency of the ACEI allele among male victims of suicide compared to male controls (odds ratio, OR = 1.69, p < 0.006), female suicides (OR = 2.01, p = 0.006) and pooled controls (OR = 1.77, p = 0.001). Analysis of genotype distribution showed that the codominant model had the best fit (p = 0.7) whereas the recessive model could be rejected (p = 0.04). Among males we found an association between the number of the ACE I allele and the method of suicide: OR = 17.98, pcorrected = 0.00003, for jumping from a height; OR = 0.36, pcorrected = 0.048, for hanging. We also observed a trend for a negative effect of the number of copies of the ACE I allele on prevalence of depression (OR = 0.36, p = 0.013) and a trend for an effect on age at death (p = 0.021). Conclusions: Our results suggest that low ACE activity associated with the I allele is a risk factor for suicide, especially in a subset of males. This may be of concern given the widespread use of drugs lowering ACE activity.

KIR2DS5 in the presence of HLA-C C2 protects against endometriosis

Endometriosis is defined as the presence of functional endometrial tissue outside the uterine cavity. Several hypotheses have attempted to explain the etiology and pathogenesis of endometriosis. Recently, it has been suggested that a defect of the natural killer (NK) activity in the recognition and lysis of endometrial cells is one of the crucial points in the development of this disease. Natural killer cells can express killer immunoglobulin-like receptors (KIR), which recognize class I human leukocyte antigens on target cells. We asked whether polymorphisms in KIR, HLA-C, and HLA-B genes are risk factors for endometriosis. We tested 153 women with endometriosis diagnosed on the basis of laparoscopic and histological examination, and 213 control healthy women, who gave birth to at least one child. The frequency of KIR genes in patients was similar to that in controls except for KIR2DS5, which exerted a protective effect only in HLA-C C2-positive individuals. Moreover, KIR2DS5-positive women with endometriosis had 13 times lower chance that the disease would occupy the peritoneum than KIR2DS5- and KIR2DS4del-negative ones (OR = 0.077, P = 0.0061). Similarly, KIR2DS4del-positive endometriotic persons had 11 times lower chance for peritoneal disease (OR = 0.094, P < 0.001). Negative linkage disequilibrium between KIR2DS5 and KIR2DS4del indicates that these genes are mutually exclusive. Our data suggest that KIR2DS5 may be associated with protection from endometriosis, whereas KIR2DS4del seems to be associated with higher disease stages, possibly by exclusion of protective KIR2DS5.