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K Kontula

Publications and source records attributed to K Kontula.

At least 19 recordsLinked to original sources
PubMed2004

CARD15 frameshift mutation in patients with CROHN disease is associated with immune dysregulation.

BACKGROUND: Mutations in the caspase-activating recruitment domain 15 (CARD15) gene are associated with Crohn disease (CD). CARD15 is an intracellular receptor for bacterial lipopolysaccharides (LPS). LPS-induced activation of transfectants containing the frameshift mutation (1007fs) of CARD15 is impaired. The aim of this study was to investigate whether the presence of CARD15 1007fs affects activation of CD patients' own cells. Patients (4 homozygotes, 6 heterozygotes, and 6 wild-type) were matched according to clinical picture and medication. METHODS: Immune inflammatory status was evaluated by measuring monocyte HLA-DR and CD11b densities and the proportion of CD14dimCD16+ monocytes, and was found to be comparable in the three groups. Blood mononuclear cells were cultured overnight in serum-free medium alone, or the medium supplemented with LPS (0.1-10.0 ng/mL), a combination of IFN-gamma (100 IU/mL) and granulocyte-macrophage colony stimulating factor (GM-CSF) (5 ng/mL), or both. TNF and IL-10 levels in the culture supernatant were determined. RESULTS: LPS 0.1 or 1.0 ng/mL alone did not increase TNF levels. IFN-gamma/GM-CSF induced TNF release, and co-culture with LPS 1.0 or 10.0 ng/mL was strongly synergistic. CARD15 1007fs mutation was linked in a gene-dose-dependent manner to low TNF release induced by IFN-gamma/GM-CSF (P value for linear trend = 0.001). The degree of synergism in co-culture was normal or high, suggesting that 1007fs did not depress responses to LPS. IL-10 levels were not related to CARD15 1007fs. CONCLUSIONS: In CD patients, CARD15 1007fs is associated in a gene-dose-dependent manner to low mononuclear cell TNF release by IFN-gamma/GM-CSF but does not impair TNF release by LPS. This type of immune dysregulation may influence susceptibility to and/or phenotype of CD.

Adult↗
PubMed2003

Melanocortin-3-receptor gene variants in morbid obesity.

BACKGROUND: Linkage and knock-out mice studies suggest that the melanocortin-3-receptor (MC3R) is a candidate gene for obesity. OBJECTIVE: To evaluate whether MC3R mutations underlie morbid obesity. SUBJECTS AND METHODS: MC3R coding and 5(')-flanking regions were sequenced in 48 subjects and the detected variants genotyped in 252 morbidly obese (BMI>/=40 kg/m(2)) Finns. Gel shifts were used to examine whether a mutation in the putative promoter alters GATA-factor binding. RESULTS: Three common MC3R variants were found: a 17C>A variant, changing Thr6-->Lys in 16%, a 241G>A variant changing Val81-->Ile in 15%, and a -239A>G substitution in the GATA binding site in 21% of the subjects. Four other variants were detected in the 5(') flanking region. Frequencies of the three common variants did not differ between obese and contol subjects. Among the obese, the 17C>A and 241G>A variants were coinherited and associated with increased insulin-glucose ratios (P<0.05) and leptin levels (P<0.05). GATA-4 bound efficiently to wild type oligonucleotide, but only weakly to the oligonucleotide with the -239A>G mutation. CONCLUSIONS: MC3R gene variants are common and do not explain human morbid obesity. These variants associated with subtle changes in onset of weight gain, hyperleptinemia and insulin-glucose ratios. The -239A>G mutation abolishes binding of GATA-4 to the MC3R promoter region.

Adult↗
PubMed2003

CARD15/NOD2 gene variants are associated with familially occurring and complicated forms of Crohn's disease.

BACKGROUND: Variants of the caspase activating recruitment domain 15/nucleotide oligomerisation domain 2 (CARD15/NOD2) gene have been associated with susceptibility to Crohn's disease (CD). AIM: Our aim was to evaluate the allele frequencies of the CARD15 variants R702W, G908R, and 1007fs in Finnish inflammatory bowel disease (IBD) patients and to search for possible associations between CARD15 variants and occurrence of familial forms of IBD or complicated forms of CD. PATIENTS AND METHODS: We investigated 198 sporadic CD patients, 46 probands with familial CD, 27 CD probands from mixed IBD families, 99 unrelated patients with ulcerative colitis (UC), and 300 control individuals for the occurrence of the CARD15 gene variants R702W, G908R, and 1007fs. RESULTS: In CD patients, the allele frequencies for the rare variants of these polymorphisms were 3.3%, 0.6%, and 4.8% (total 8.7%), and the corresponding frequencies in healthy controls were 1.8%, 0%, and 1.7% (total 3.5%) (8.7% v 3.5%; p<0.01). In UC patients allele frequencies were comparable with those in controls. The frequency of the 1007fs polymorphism variant allele was significantly higher among all CD patients than in controls (4.8% v 1.7%; p<0.01) but there was no significant difference in allele frequencies between the CD and UC groups. The 1007fs allele frequency was higher in familial CD than in non-familial cases with CD (10.9% v 3.5%; p<0.01). There were no significant differences in the allele frequencies of the R702W and G908R polymorphisms between CD patients, UC patients, and controls. We found that 15.5% of CD patients, 9.1% of UC patients, and 6.7% of controls carried at least one of the CARD15 variants. In CD patients carrying at least one of the three NOD2 variants, the ileum was affected more often than in non-carrier CD patients (90% v 73%; p<0.05), they had stricturing or penetrating disease more often than non-carriers (88% v 56%; p<0.01), and they had an increased need for bowel surgery. CONCLUSIONS: The frequency of NOD2 gene variants was lower in genetically homogenous Finns than in other populations. The 1007fs variant was associated with CD. The occurrence of CARD15 variants predicted ileal location as well as stricturing and penetrating forms of CD.

Adolescent↗
PubMed2002

Familial and sporadic inflammatory bowel disease: comparison of clinical features and serological markers in a genetically homogeneous population.

BACKGROUND: The familial occurrence of inflammatory bowel disease (IBD) and the clinical features of familial and sporadic IBD in the genetically homogeneous Finnish population are evaluated. METHODS: 257 patients with Crohn disease (CD) and 436 with ulcerative colitis (UC) participated in the study. They were asked whether IBD was present (familial IBD) or absent (sporadic IBD) in their first-degree relatives. Data on the clinical course of the disease were collected from the patient records. Antibodies to Saccharomyces cerevisiae (ASCA) and anti-neutrophil cytoplasmic antibodies (ANCA) were determined from serum samples. RESULTS: Affected first-degree relatives were found in 15.6% of patients with CD and in 13.8% of patients with UC. In familial cases CD was more often located in the ileum (38% versus 21%) and less often in the ileocolon (35% versus 50%) (P< 0.05) than in sporadic cases. A greater percentage of CD patients than UC patients were smokers (47% versus 13%; P < 0.01). An elevated level of IgA and/or IgG antibodies for ASCA was found more often in CD patients than in UC patients (59% versus 14%; P < 0.01), while pANCA were found more often in UC than in CD patients (48% versus 12%; P < 0.01). The combination of pANCA-ASCA+ yielded a sensitivity, specificity and positive predictive value of 48%, 92% and 90%, respectively, for CD, and the combination of pANCA + ASCA- of 55%, 94% and 90%, respectively, for UC. CONCLUSIONS: The percentage of familial IBD cases in Finland is comparable to that reported elsewhere in Europe. No important clinical differences between patients with familial and sporadic forms of the disease were found. ASCA is associated with both familial and sporadic CD and pANCA with UC, but low sensitivity diminishes their value as a serological marker of IBD or as a differential diagnostic test between CD and UC.

Adolescent↗
PubMed2001

Prevalence of Alzheimer's disease in very elderly people: a prospective neuropathological study.

BACKGROUND: No previous autopsy-controlled, prospective, and population-based studies are available on the prevalence of AD in very elderly people. OBJECTIVE: To study the point prevalence of neuropathologically defined AD in a population of people at least 85 years of age, stratified according to their APOE genotype. METHODS: A population-based sample of 532 (of a total population of 601) elderly Finnish individuals, aged 85 years or more, were clinically tested for dementia in 1991 (with follow-up studies of the survivors in 1994, 1996, and 1999) and genotyped for APOE. An autopsy involving neuropathologic diagnosis of AD according to modified consensus criteria was performed in 118 of 198 deceased subjects who had been demented on April 1, 1991, and in 62 of 201 nondemented individuals. RESULTS: The prevalence of neuropathologically defined AD was 33%, whereas the prevalence of clinically diagnosed AD was 16%. There was a highly significant (p < 0.001) association between the APOE epsilon4 allele and AD: Sixty-three percent of APOE epsilon4 carriers and 20% of noncarriers had neuropathologic AD. The respective figures in subjects aged 90 years or more were 71 and 22%. CONCLUSIONS: The prevalence of neuropathologically defined AD is higher than that reported in most previous studies based on clinical diagnosis. The discrepancy between the neuropathologic and clinical diagnoses of AD in very elderly subjects may affect the results of population-based studies. The APOE genotype has a strong effect on the prevalence of neuropathologically defined AD, even after 90 years of age.

Aged↗
PubMed2001

Mutations of the cardiac ryanodine receptor (RyR2) gene in familial polymorphic ventricular tachycardia.

BACKGROUND: Familial polymorphic ventricular tachycardia is an autosomal-dominant, inherited disease with a relatively early onset and a mortality rate of approximately 30% by the age of 30 years. Phenotypically, it is characterized by salvoes of bidirectional and polymorphic ventricular tachycardias in response to vigorous exercise, with no structural evidence of myocardial disease. We previously mapped the causative gene to chromosome 1q42-q43. In the present study, we demonstrate that patients with familial polymorphic ventricular tachycardia have missense mutations in the cardiac sarcoplasmic reticulum calcium release channel (ryanodine receptor type 2 [RyR2]). METHODS AND RESULTS: In 3 large families studied, 3 different RyR2 mutations (P2328S, Q4201R, V4653F) were detected and shown to fully cosegregate with the characteristic arrhythmic phenotype. These mutations were absent in the nonaffected family members and in 100 healthy controls. In addition to identifying 3 causative mutations, we identified a number of single nucleotide polymorphisms that span the genomic structure of RyR2 and will be useful for candidate-based association studies for other arrhythmic disorders. CONCLUSIONS: Our data illustrate that mutations of the RyR2 gene cause at least one variety of inherited polymorphic tachycardia. These findings define a new entity of disorders of myocardial calcium signaling.

Base Sequence↗
PubMed2001

A founder mutation of the potassium channel KCNQ1 in long QT syndrome: implications for estimation of disease prevalence and molecular diagnostics.

OBJECTIVES: We took advantage of the genetic isolate of Finns to characterize a common long QT syndrome (LQTS) mutation, and to estimate the prevalence of LQTS. BACKGROUND: The LQTS is caused by mutations in different ion channel genes, which vary in their molecular nature from family to family. METHODS: The potassium channel gene KCNQ1 was sequenced in two unrelated Finnish patients with Jervell and Lange-Nielsen syndrome (JLNS), followed by genotyping of 114 LQTS probands and their available family members. The functional properties of the mutation were studied using a whole-cell patch-damp technique. RESULTS: We identified a novel missense mutation (G589D or KCNQ1-Fin) in the C-terminus of the KCNQ1 subunit. The voltage threshold of activation for the KCNQ1-Fin channel was markedly increased compared to the wild-type channel. This mutation was present in homozygous form in two siblings with JLNS, and in heterozygous form in 34 of 114 probands with Romano-Ward syndrome (RWS) and 282 family members. The mean (+/- SD) rate-corrected QT intervals of the heterozygous subjects (n = 316) and noncarriers (n = 423) were 460 +/- 40 ms and 410 +/- 20 ms (p < 0.001), respectively. CONCLUSIONS: A single missense mutation of the KCNQ1 gene accounts for 30% of Finnish cases with LQTS, and it may be associated with both the RWS and JLNS phenotypes of the syndrome. The relative enrichment of this mutation most likely represents a founder gene effect. These circumstances provide an excellent opportunity to examine how genetic and nongenetic factors modify the LQTS phenotype.

Adolescent↗
PubMed2001

Relation of collagen type I alpha 1 (COLIA 1) and vitamin D receptor genotypes to bone mass, turnover, and fractures in early postmenopausal women and to hip fractures in elderly people.

Background: In a previous study, we showed an association between the vitamin D receptor (VDR) gene BsmI restriction fragment polymorphism and peak bone mass in young Finnish adults. Design: The previous finding prompted us to study the relationship of the same polymorphism, as well as of the polymorphism in the Sp1 binding site of the collagen type I alpha 1 (COLIA 1) gene, to bone mineral density (BMD). BMD was measured by dual-energy X-ray absorptiometry and adjusted for age, weight, height, and lifestyle factors. Also studied was the relationship of VDR and COLIA 1 genotypes to markers of bone turnover [serum osteocalcin, type I procollagen carboxy- (PICP), and aminoterminal (PINP) propeptide, and type I collagen carboxyterminal telopeptide (ICTP)] and bone fractures in 513 early postmenopausal women (1-5 years postmenopausal), as well as hip fractures in 172 very old people. Results: The BB, Bb, and bb genotypes of the VDR gene, as well as the SS, Ss, and ss genotypes of the COLIA 1 gene, were distributed similarly among 402 early postmenopausal women with osteopenia in the lumbar spine and among 111 women with normal BMD (P=0.12 for VDR, P=0.53 for COLIA 1). There was no relation between the VDR and COLIA 1 genotypes and lumbar spine BMD among osteopenic women, among normal women, or in the combined study population. Among the women with vertebral osteopenia, the femoral neck BMD did not associate significantly with the VDR or COLIA 1 polymorphisms. The frequencies of the different VDR and COLIA 1 genotypes were similar among women with or without a history of a low-energy fracture. There was a borderline association between the VDR genotype and serum osteocalcin concentrations, with the Bb genotype associated with the highest median level (P=0.037). In a population-based sample of very old individuals (>85 years), the frequencies of the different VDR and COLIA 1 genotypes were similar among those with (n=64) and without (n=108) a history of hip fracture. Conclusion: The present data suggest that, in the Finnish population, the VDR and COLIA 1 genotypes do not determine the bone mass of early postmenopausal women or their bone turnover rate. The polymorphisms are not associated with risk of hip fractures in elderly people or with low-energy fractures in early postmenopausal women.

Journal Article↗
PubMed2001

Does apolipoprotein E influence learning and memory in the nondemented oldest old?

The objective of this study was to analyze the relationship of the apolipoprotein E (apoE) epsilon4 and epsilon2 alleles to learning and memory performances in the nondemented oldest old. Forty-six nondemented persons aged 85 years or over from a randomly selected group of 128 subjects in Vantaa, Finland, were studied. ApoE genotyping was performed using the minisequencing technique. A structured clinical examination and interview were carried out. The test variables studied were learning and memory scores (from the Fuld Object-Memory Evaluation), verbal fluency, and conceptualization (the Similarities subtest of the WAIS-R). We compared apoE-epsilon4 carriers to noncarriers and apoE-epsilon2 carriers to noncarriers. No statistically significant differences were found in any of the test variables. The results failed to confirm the hypotheses that poor cognitive performance is associated with the apoE-epsilon4 allele and good performance with the apoE-epsilon2 allele in the oldest old. This suggests that the apoE alleles do not have a detectable relationship to learning and memory in nondemented very elderly people.

Aged↗
PubMed2001

Genetic analysis in Finnish families with inflammatory bowel disease supports linkage to chromosome 3p21.

In inflammatory bowel diseases (IBD), certain chromosomal candidate loci have been repeatedly identified by independent studies in different populations. To investigate the contribution of the loci on chromosomes 1, 3, 7, 12, 14, and 16 to the susceptibility of IBD in Finnish population, where the predominant feature is the excess of ulcerative colitis (UC) families compared to Crohn's disease (CD) families, we carried out linkage analyses using 93 Finnish, multiply-affected IBD families. We observed nominal evidence for linkage to chromosome 3p21, consistent with earlier reports. The lod scores peaked at D3S2432, with a maximum two-point lod score of 1.68 (P=0.0027). In addition, we studied whether risk of IBD is associated with functional variants of two positional candidate genes; the chemokine receptor CCR5 gene on chromosome 3p21 and the interleukin-4 receptor alpha-subunit gene (IL4RA) on chromosome 16. We did not find any significant correlation between a 32-bp deletion variant of CCR5 or a single nucleotide change A1902G (Gln576Arg) of IL4RA, and IBD phenotypes, with the exception that in the UC group homozygosity for the G1902 allele of IL4RA was less frequent (0.019 vs 0.049, P=0.038). In conclusion, our study, carried out in a genetically homogenous population, suggests that chromosome 3 may contain a susceptibility gene for IBD.

Alleles↗
PubMed2001

Response of the QT interval to mental and physical stress in types LQT1 and LQT2 of the long QT syndrome.

OBJECTIVE: To study and compare the effects of mental and physical stress on long QT syndrome (LQTS) patients. DESIGN: Case-control study. MAIN OUTCOME MEASURES: QT intervals were measured from lead V3. Serum potassium and plasma catecholamine concentrations were also monitored. PATIENTS: 16 patients with type 1 LQTS (LQT1), 14 with type 2 LQTS (LQT2), both groups asymptomatic, and 14 healthy control subjects. INTERVENTIONS: Three types of mental stress tests and a submaximal exercise stress test. RESULTS: Heart rate responses to mental stress and exercise were similar in all groups. During mental stress, the mean QT interval shortened to a similar extent in controls (-29 ms), LQT1 patients (-34 ms), and LQT2 patients (-30 ms). During exercise, the corresponding QT adaptation to exercise stress was more pronounced (p < 0.01) in healthy controls (-47 ms) than in LQT1 (-38 ms) or LQT2 patients (-38 ms). During exercise changes in serum potassium concentrations were correlated to changes in QT intervals in controls, but not in LQTS patients. LQT1 and LQT2 patients did not differ in serum potassium, catecholamine or heart rate responses to mental or physical stress. CONCLUSIONS: QT adaptation to mental and exercise stress in healthy people and in patients with LQTS is different. In healthy people QT adaptation is more sensitive to physical than to mental stress while no such diverging pattern was seen in asymptomatic LQTS patients.

Adolescent↗
PubMed2001

Familial hypercholesterolaemia in Finland: common, rare and mild mutations of the LDL receptor and their clinical consequences. Finnish FH-group.

Familial hypercholesterolaemia (FH) is an autosomal co-dominantly inherited condition resulting from mutations of the low-density lipoprotein (LDL) receptor which occur in heterozygous form in approximately one in 500 individuals. Clinically, FH is characterized by 2-3-fold elevation of serum LDL cholesterol levels, accelerated development of atherosclerotic vascular disease, and, if untreated, shortened lifespan. The Finnish population, which represents a genetic isolate, offers exceptional possibilities for genetic-epidemiological studies on FH, as a handful of founder gene mutations account for the majority of FH cases in Finland. This review summarizes data from our FH studies carried out since 1985. We wish to emphasize the continuum of genotype-phenotype relationships, the importance of molecular diagnosis, the detection of novel risk factors of vascular disease, and innovations inhibiting cholesterol absorption for the modern treatment of FH.

Age of Onset↗
PubMed2001

Association of lipoprotein lipase Ser447Ter polymorphism with brain infarction: a population-based neuropathological study.

BACKGROUND: Variants of the lipoprotein lipase (LPL) gene have been shown to influence serum lipid levels, risk of coronary heart disease and, as found recently, risk of clinical ischaemic cerebrovascular disease. Here we tested for an association between brain infarction and two common polymorphisms of the LPL gene, Ser447Ter and Asn291 Ser. METHOD: To avoid ascertainment and selection bias involved in many association studies, we compared the distribution of these polymorphisms in neuropathologically verified patients (n = 119) vs controls (n = 133) derived from a prospective, population-based study (the Vantaa 85+ study). RESULTS: The LPL Ter447 variant was negatively associated with neuropathologically verified brain infarcts (P = 0.006), and even more strongly with small brain infarcts (P = 0.004). In addition, we found that the Ter447 variant was associated with higher serum HDL chblesterol (P = 0.004) and lower triglyceride levels (P= 0.003), and that it was negatively associated with pathologically verified severe coronary artery disease (P=0.001) in the Vantaa 85+ study sample. The Asn291Ser polymorphism was not significantly associated with brain infarction. CONCLUSION: The Ter447 variant of LPL is associated with decreased risk of brain infarction and coronary artery disease in our very elderly population.

Aged↗
PubMed2001

HFE haemochromatosis gene mutations in liver transplant patients.

BACKGROUND: The majority of patients with inherited haemochromatosis carry two mutant alleles of the recently discovered HFE gene. Individuals heterozygous for the HFE mutation could be predisposed to end-stage liver disease due to other causes. METHODS: The frequencies of the HFE gene mutations C282Y and H63D were determined in DNA samples obtained from 189 liver transplant patients and 225 healthy Finnish blood donors. RESULTS: 5% of the 189 liver transplant recipients were heterozygotes and 0.5% homozygotes for the C282Y mutation, while 16% were heterozygotes and 0.5% homozygotes for the H63D mutation. These figures were not increased in comparison to controls, of whom 11% were C282Y heterozygotes, 16% H63D heterozygotes and 0.9% H63D homozygotes. Among recipients with acute non-A-E hepatitis (n = 31), the frequency of the H63D allele was higher than in controls (21% versus 9.1%, P < 0.01). Perls' stain for iron in explanted liver specimens was positive in 28% of recipients with alcoholic cirrhosis, 26% of patients with acute non-A-E hepatitis and 14% in the rest of the recipients. The HFE genotypes did not correlate with the iron status. CONCLUSION: Individuals heterozygous for either the C282Y or H63D mutation of the HFE gene are not at increased risk of developing chronic end-stage liver disease. However, subjects heterozygous for the H63D mutation may have an increased risk to develop fulminant non-A-E hepatitis.

Adolescent↗
PubMed2000

Cardiovascular risk factors and Alzheimer's disease: a genetic association study in a population aged 85 or over.

Increasing evidence suggests a relation between vascular disorders and late-onset Alzheimer's disease (AD). We performed an association analysis of low-density lipoprotein receptor-related protein (LRP), lipoprotein lipase (LPL), and angiotensin converting enzyme (ACE) genes, known to be involved in vascular disorders, and AD. Genotyping was carried out in 113 patients with clinically defined Alzheimer's disease (NINCDS-ADRDA criteria) and 203 non-demented controls in a prospective, population-based study of people aged 85 years or over (Vantaa 85+ Study). Corresponding analysis was performed on 121 neuropathologically verified AD patients (CERAD criteria) and 75 controls derived from the same study population. We did not find significant associations between the polymorphisms studied and AD. However, analysis of the LPL polymorphism showed a weak trend (uncorrected P-value 0.095) towards protection against neuropathologically defined AD. Our study is based on very elderly Finns. Therefore, further studies are warranted in other populations.

Aged↗