No association between a neuronal nitric oxide synthase (NOS1) gene polymorphism on chromosome 12q24 and bipolar disorder.
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Publications and source records attributed to T A Kruse.
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Patients with schizophrenia (n=11) and bipolar affective disorder (n=17) from the relatively isolated population of the Faroe Islands were genotyped for 34 polymorphic markers on chromosome 4 in a search for allelic association and haplotype sharing among distantly related patients. When considering bipolar patients only, there was no clearcut support for any region on chromosome 4. The two-marker segment D4S394-D4S2983 at 4p16.1 was, however, supported by a P-value of 0.0162. For patients with schizophrenia, there was reasonable support for 4p16.1 as marker D4S2281 (P=0.0019), a two-marker segment (D4S2281-D4S1605, P=0.0009) and a three-marker segment (D4S2923-D4S2928-D4S1582, P-0.0005) appeared to be associated with schizophrenia, with some alleles/haplotypes occurring with different frequencies in patients compared to controls. When combining both psychiatric disorders, chromosome 4p16.1 received further support from five partially overlapping two- and three-marker segments (D4S394-D4S2983, P=0.0039; D4S2281-D4S1605, P=0.0027 and D4S394-D4S2983-D4S2923, P=0.006; D4S2923-D4S2928-D4S1582, P=0.00007; D4S1582-D4S1599-D4S2281, P=0.005). Increased haplotype sharing in patients with schizophrenia and in the combined data set was partly supported by Fisher's exact test and tests based on the genealogy. Our study yields support for a common risk gene for schizophrenia and bipolar affective disorder on the short arm of chromosome 4, as suggested by previous findings in the neighbouring Scottish population.
BACKGROUND: Type I allergy globally affects an increasing number of individuals with the consequence of considerable personal morbidity and socio-economic costs. Identification of disease susceptibility genes would render enormous medical perspectives in terms of improved diagnosis, treatment and prevention. Like for other complex disorders, achievement of the knowledge necessary depends on confirmation of reported genomic candidate regions. METHODS: We performed a two-stage fine-scale linkage analysis in 11 selected candidate regions on chromosome 3p, 3q, 4p, 4q, 5q, 6p, 9p, 12q, 12qter, 18q and Xp. We analysed 97 polymorphic markers in 424 individuals from 100 sib-pair families and evaluated the data for five phenotypes: Allergic asthma, atopic dermatitis, allergic rhinitis and total and specific immunoglobulin E. RESULTS: The highest maximum likelihood scores (MLS) were obtained on chromosomes 3q (MLS = 2.69), 4p (MLS = 2.34), 4q (MLS = 2.75), 6p (MLS = 2.22), 12qter (MLS = 2.15) and Xp (MLS = 2.23). All five phenotypes showed MLS >/= 2 in one or more of the candidate regions. CONCLUSIONS: Susceptibility genes in the 3q, 4q and Xp regions may play a central role in the inheritance of allergic disease, as positive results were obtained for all five phenotypes in these three regions.
Dopa decarboxylase (DDC) catalyses the synthesis of both dopamine and serotonin as well as trace amines suggested to possess neuromodulating capabilities. We have previously reported evidence suggesting an association between DDC and bipolar affective disorder (BPAD) [Børglum et al., 1999]. To further investigate the possible role of DDC in BPAD, we analyzed a 1- and a 4-bp deletion variant-both of putative functional significance-in two new samples: a case-control sample with 140 cases and 204 controls, and 100 case-parents trios. We also tested for association in subjects with familial disease in both the new and the previously investigated samples. The previously reported association was not replicated in either of the new samples. However, a preponderance of the 1-bp deletion was increased by analysis of the familial cases separately for all case-control samples investigated, indicating a possible association with familial disease (combined analysis, P = 0.02). In the trio sample, a preferential paternal transmission of the 4-bp deletion was observed (P = 0.006). DDC is located next to the imprinted gene GRB10, which is expressed specifically from the paternal allele in fetal brains. Increased transmission of paternal DDC alleles has also been suggested in attention deficit hyperactivity disorder. We suggest that DDC might confer susceptibility to BPAD predominantly when paternally transmitted.
In this paper, we apply logistic regression models to measure genetic association with human survival for highly polymorphic and pleiotropic genes. By modelling genotype frequency as a function of age, we introduce a logistic regression model with polytomous responses to handle the polymorphic situation. Genotype and allele-based parameterization can be used to investigate the modes of gene action and to reduce the number of parameters, so that the power is increased while the amount of multiple testing minimized. A binomial logistic regression model with fractional polynomials is used to capture the age-dependent or antagonistic pleiotropic effects. The models are applied to HFE genotype data to assess the effects on human longevity by different alleles and to detect if an age-dependent effect exists. Application has shown that these methods can serve as useful tools in searching for important gene variations that contribute to human aging and longevity.
Chromosome 22q may harbor risk genes for schizophrenia and bipolar affective disorder. This is evidenced through genetic mapping studies, investigations of cytogenetic abnormalities, and direct examination of candidate genes. Patients with schizophrenia and bipolar affective disorder from the Faroe Islands were typed for 35 evenly distributed polymorphic markers on 22q in a search for shared risk genes in the two disorders. No single marker was strongly associated with either disease, but five two-marker segments that cluster within two regions on the chromosome have haplotypes occurring with different frequencies in patients compared to controls. Two segments were of most interest when the results of the association tests were combined with the probabilities of identity by descent of single haplotypes. For bipolar patients, the strongest evidence for a candidate region harboring a risk gene was found at a segment of at least 1.1 cM including markers D22S1161 and D22S922 (P=0.0081 in the test for association). Our results also support the a priori evidence of a susceptibility gene to schizophrenia at a segment of at least 0.45 cM including markers D22S279 and D22S276 (P=0.0075). Patients were tested for the presence of a missense mutation in the WKL1 gene encoding a putative cation channel close to segment D22S1161--D22S922, which has been associated with schizophrenia. We did not find this mutation in schizophrenic or bipolar patients or the controls from the Faroe Islands.
BACKGROUND: Allergic asthma is an increasingly common disease of complex inheritance. Several studies have suggested candidate regions, but genetic heterogeneity, ethnic differences and varying study designs may in part explain the lack of identified and confirmed susceptibility genes. Investigation of different populations will further clarify the topic. We therefore evaluated allergic asthma and increased total and specific IgE in 39, 45 and 57 sib-pairs from 100 Danish allergy families. METHODS: Affected sib-pairs meeting a narrow phenotype definition were selected for the three phenotypes atopy, allergic asthma and increased total IgE. We performed a total genome scan using 446 microsatellite markers and obtained nonparametric linkage results from the MAPMAKER/SIBS computer program. RESULTS: Our study revealed four candidate regions (MLS > 2) on chromosome 1p36, 3q21-q22, 5q31 and 6p24-p22, and 15 candidate regions (1 < MLS < 2) that may contain susceptibility genes for asthma and atopy. We did not find linkage to the candidate genes TNF-beta, FcER1beta and Il4R-alpha, except for weak support for linkage of the asthma phenotype to TNF-beta (MLS = 1.18). CONCLUSIONS: We found evidence for two new asthma and atopy loci, 1p36 and 3q21-q22, and supported linkage in the Danish population to seven previously reported candidate regions.
The somatostatin receptor 5 (SSTR5) gene is a candidate gene for bipolar affective disorder (BPAD) as well as for other neuropsychiatric disorders. The gene is positioned on chromosome 16p13.3, a region that has been implicated by a few linkage studies to potentially harbor a disease susceptibility gene for BPAD. Recent evidence shows that the dopamine D2 receptor (DRD2) and SSTR5 interact physically to form heterodimers with enhanced functional activity. Brain D2 dopamine receptors are one of the major targets of neuroleptic treatments in psychiatric disorders. In this study we systematically screened the promoter and coding region of the SSTR5 gene for genetic variation that could contribute to the development of neuropsychiatric disorders. Eleven novel single nucleotide polymorphisms (SNPs) were identified including four missense SNPs, Leu48Met, Ala52Val, Pro109Ser and Pro335Leu. We carried out an association study of BPAD using 80 Danish cases and 144 control subjects, and replication analysis using 55 British cases and 88 control subjects. For the Danish population, association was suggested between silent SNP G573A and BPAD (P = 0.008). For the British population we found association to BPAD with missense mutation Leu48Met (P = 0.003) and missense mutation Pro335Leu (P = 0.004). The statistical significance of the association was, however, greatly reduced after correcting for multiple testing. When combining genotypes from Leu48Met and Pro335Leu into haplotypes, association to BPAD was found in the British population (P = 0.0007). This haplotype association was not replicated in the Danish population. Our results may indicate that the SSTR5 gene is involved in the etiology of BPAD or may exist in linkage disequilibrium with a susceptibility gene close to SSTR5. However, given the marginal statistical significance and the potential for false-positive results in association studies with candidate genes, further studies are needed to clarify this hypothesis.
The present study reports a genomewide scan using linkage analysis for risk genes involved in bipolar disorder with 613 microsatellite markers including additional testing of promising regions. As previously published significant linkage was obtained at chromosome 12q24.3 with a two-point parametric lod score of 3.42 at D12S1639 including all members in both families (empirical P-value 0.00004, genome-wide P-value 0.0417). The multipoint parametric lod score at D12S1639 was 3.63 (genome-wide P-value 0.0265). At chromosome 1p22-p21 a parametric, affecteds-only two-point lod score of 2.75 at marker D1S216 was found (empirical P-value 0.0002, genome-wide P-value 0.1622). A three-point lod score of 2.98 (genome-wide P-value 0.1022) at D1S216, and a multipoint non-parametric analysis with a maximum NPL-all score of 17.60 (P-value 0.00079) at D1S216 further supported this finding. A number of additional loci on chromosomes 4p16, 6q14-q22, 10q26 and 16p13.3 yielded parametric lod scores around or above 2.
BACKGROUND: Several susceptibility genes for atopy have been suggested in recent years. Few have been investigated as intensively as the interleukin-4-receptor alpha (IL4Ralpha) gene on chromosome 16. The results remain in dispute. Therefore, in a robust design, we tested for association of type I allergy to the IL4R variations I50V and Q576R, and investigated chromosome 16 for atopy candidate regions in general. METHODS: We identified 100 Danish allergy sib-pair families. Five conservative phenotypes for type I allergy were defined and evaluated. The IL4R variations were genotyped in trios and evaluated by the transmission disequilibrium test (TDT). Multipoint linkage analysis and exclusion mapping were conducted with sib-pairs analyzed for 17 microsatellite markers. RESULTS: No evidence for association or linkage to the IL4R polymorphisms was found (P values: 0.12-0.90). Linkage analysis did not support linkage of any of the phenotypes to chromosome 16. Major parts of chromosome 16 were excluded as candidate regions harboring oligogenes for type I allergy. CONCLUSION: We found chromosome 16 unlikely to harbor strong candidate genes for type I allergy. The role of the IL4Ralpha gene in the inheritance of atopy was insignificant in the Danish population. The use of conservative allergy phenotypes in the search for genes predisposing to atopic disease was discussed.
Seckel syndrome (MIM 210600) is a rare autosomal recessive disorder with a heterogeneous appearance. Key features are growth retardation, microcephaly with mental retardation, and a characteristic 'bird-headed' facial appearance. We have performed a genome-wide linkage scan in a consanguineous family of Iraqi descent. By homozygosity mapping a new locus for the syndrome was assigned to a approximately 30 cM interval between markers D18S78 and D18S866 with a maximum multipoint lod score of 3.1, corresponding to a trans-centromeric region on chromosome 18p11.31-q11.2. This second locus for Seckel syndrome demonstrates genetic heterogeneity and brings us a step further towards molecular genetic delineation of this heterogeneous condition.
Allergic rhinitis is a common disease of complex inheritance and is characterised by mucosal inflammation caused by allergen exposure. The genetics of closely related phenotypes such as asthma, atopy and to some extend atopic dermatitis has attracted attention in recent years. Genetic reports of allergic rhinitis on the contrary have as yet been most sparse. To identify candidate regions holding genes for allergic rhinitis we performed a total genome-scan on affected sib-pair families. From 100 Danish sib-pair families selected for allergy, families containing sib-pairs matching a phenotype definition of both clinical allergic rhinitis and confirmed specific allergy were chosen. Thirty-three affected sib-pair families qualified for the scan that was undertaken using 446 microsatellite markers. Non-parametric linkage results were obtained from MAPMAKER/SIBS computer program. The study revealed one major candidate region on chromosome 4q24-q27 (LOD=2.83) and eight minor candidate regions 2q12-q33, 3q13, 4p15-q12, 5q13-q15, 6p24-p23, 12p13, 22q13, and Xp21 (LOD=1.04-1.63) likely to contain susceptibility genes for allergic rhinitis. Our findings did not support a previous report of linkage of allergic rhinitis to chromosome 12q14-q24 but they added positive evidence to the asthma and atopy candidate regions 2q33 and 6p23. Further identification of the specific genes involved in allergic rhinitis will give opportunities for improved diagnosis and treatment.
A number of studies have strongly suggested a susceptibility locus for bipolar affective disorder on chromosome 12q24. The present study investigates for a shared chromosomal segment among distantly related patients with bipolar affective disorder from the Faroe Islands, using 17 microsatellite markers covering 24 cM in the previously suggested region on chromosome 12q24. D12S342 showed possible allelic association to bipolar affective disorder (P-value using CLUMP below 0.01). Increased sharing among cases of two-marker haplotypes were suggested at D12S1614--D12S342 (P-values using CLUMP below 0.01), and D12S2075--D12S1675 (P-values using CLUMP around 0.001). The region of most interest is around 6 cM and bounded by markers D12S1614 and D12S1675 as suggested by the interesting two-marker haplotypes. This area contains the minimum interesting region between D12S342 and D12S1658 suggested by the previously reported haplotypes in the two Danish families with bipolar affective disorder.
Several lines of evidence implicate dopa decarboxylase (DDC) with schizophrenia. By analysis of two putative functional DDC variants in 173 schizophrenic patients and 204 controls we tested the hypotheses that DDC is involved in: (1) predisposition to schizophrenia; and (2) modulation of age at disease onset. No association was observed with schizophrenia as a whole, whereas an association between DDC genotypes and age at disease onset was suggested in males (P = 0.03). This association was most pronounced in relation to genotypes of haplotypes comprising both variants, suggesting an additive model where one variant mediates early and the other late onset. Accordingly, the haplotype-based genotypes could be assigned into three groups by their possible relative effect on age at onset: an "early", "neutral" and "late" group. Dividing the male schizophrenics into four groups with increasing age at onset, the "early" genotypes were seen to decrease in frequency from 51.5% to 16.7% while the "late" genotypes increased from 12.1% to 33.3% (P = 0.02). The difference in mean age at onset between male patients with "early" genotypes vs patients with "late" genotypes was close to 5 years (95% CI: 0.7-8.8). Thus, DDC may possibly act as a modulator of age at onset in male schizophrenics.
The search for chromosome regions that potentially harbour susceptibility genes for diseases by investigating the inheritance of disease and DNA markers in groups of patients is the initial step in the identification of the specific genes involved. The identification of genes involved in disease susceptibility is one of the main research strategies for unravelling the etiology and pathophysiology of many common diseases. However, such diseases often have a complex etiology which makes the genetic mapping of the involved disease genes very difficult. Fortunately, a number of different methods exist for genetic mapping of disease genes.
The molecular genetics of the autosomal recessive disorder pycnodysostosis was studied in five independent families from an outbred Caucasian population. We found two new mutations and one recently described mutation in the cathepsin K gene by sequencing DNA from eight patients with pycnodysostosis: a one base transition in exon8, c926T > C, causing a single amino acid substitution leucine-->proline, L309P; A 3' splice site mutation in intron 2, c121-1G > A, causing deletion of all exon 3, 41V-81Mdel; and the exon 3 missense mutation c236G > A leading to residue G79E. In three of the families patients were homozygous for 926T > C. In the remaining two families patients were heterozygous for 926T > C and 121-1G > A in one case, and for 926T > C and 236G > A in the other case. Assays using genomic DNA were developed for all three mutations. We tested 150 healthy control persons and observed the mutation frequencies: 0 to 300 for 121-1G > A and 236G > A and 1 to 150 for 926T > C. One patient from each family was haplotyped with eight microsatellite markers surrounding the cathepsin K gene on chromosome 1q21. A very rare, P = 1.8 x 10(-6) to P = 0.0004, and highly preserved area around the presumed disease locus was common to all the patients. This haplotype was found on seven chromosomes identical by state, IBS, out of the possible eight carrying the 926T > C mutation. Founder effect, locus homogeneity, and allele heterogeneity regarding pycnodysostosis within this population are discussed. Finally, the first pregnancy and delivery described in a patient with pycnodysostosis is reported.
We report here our genetic findings of a family in which 14 members were affected with isolated primary hyperparathyroidism. Hyperparathyroidism is the main feature of multiple endocrine neoplasia type 1 (MEN1), making the recently cloned MEN1 gene a prime candidate gene in this family. Significantly positive lod scores were achieved with D11S4946 (3.36) and D11S4940 (3.53), and by combining the results from these two markers, a maximum positive lod score of 4.12 at recombination fraction 0.00 was obtained. Mutation analysis of MEN1 performed by full sequencing identified a missense mutation in exon 4, causing an amino acid change from glutamine to proline at codon 260. This mutation (Q260P) was present in all affected family members, and the inheritance of the mutation was in complete agreement with the disease-associated haplotype. In comparison with the recent functional studies of the menin protein interactions, this mutation is located in a region with little or no binding activity to JunD and activating protein-1 transcription factor. We conclude that some of the familial isolated primary hyperparathyroidism families constitute a milder variant of MEN 1, which is associated with a functionally milder missense mutation.
We identified the alpha-cardiac actin gene (ACTC) as a novel disease gene in a pedigree suffering from familial hypertrophic cardiomyopathy (FHC). Linkage analyses excluded all the previously reported FHC loci as possible disease loci in the family studied, with lod scores varying between -2.5 and -6.0. Further linkage analyses of plausible candidate genes highly expressed in the adult human heart identified ACTC as the most likely disease gene, showing a maximal lod score of 3.6. Mutation analysis of ACTC revealed an Ala295Ser mutation in exon 5 close to 2 missense mutations recently described to cause the inherited form of idiopathic dilated cardiomyopathy (IDC). ACTC is the first sarcomeric gene described in which mutations are responsible for 2 different cardiomyopathies. We hypothesize that ACTC mutations affecting sarcomere contraction lead to FHC and that mutations affecting force transmission from the sarcomere to the surrounding syncytium lead to IDC.