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S Nanko

Publications and source records attributed to S Nanko.

At least 73 records · Page 4Linked to original sources
PubMed1995

Systematic search for major genes in schizophrenia: methodological issues and results from chromosome 12.

We describe a method of systematically searching for major genes in disorders of unknown mode of inheritance, using linkage analysis. Our method is designed to minimize the probability of missing linkage due to inadequate exploration of data. We illustrate this method with the results of a search for a locus for schizophrenia on chromosome 12 using 22 highly polymorphic markers in 23 high density pedigrees. The markers span approximately 85-90% of the chromosome and are on average 9.35 cM apart. We have analysed the data using the most plausible current genetic models and allowing for the presence of genetic heterogeneity. None of the markers was supportive of linkage and the distribution of the heterogeneity statistics was in accordance with the null hypothesis.

Chromosomes, Human, Pair 12↗
PubMed1995

No evidence for linkage between the X-chromosome marker DXS7 and schizophrenia.

DeLisi et al. (1994b) have examined the X and Y chromosomes for linkage to schizophrenia in 126 small families and report a small positive LOD score for the marker DXS7, adjacent to the MAO locus at Xp11.4-11.3. Because of this, we have examined the DXS7 for linkage to schizophrenia using 17 pedigrees in which male-to-male transmission of schizophrenia was absent. Alleles at DXS7 were genotyped using the PCR and LOD scores calculated using five models of inheritance, including classical dominant recessive and intermediate models. LOD scores were substantially negative for all models examined and analysis for linkage heterogeneity using the LOD2 method showed no significance. Analysis by the nonparametric affected sib-pair method likewise indicated no linkage. We conclude that DXS7 is not a major locus for schizophrenia in our collection of pedigrees.

Family↗
PubMed1995

No evidence of linkage or association between tyrosine hydroxylase gene and affective disorder.

Tyrosine hydroxylase (TH) is the rate-limiting enzyme in the synthesis of dopamine and norepinephrine, and therefore is of significant interest as a candidate gene in studies of affective disorders. We have carried out the linkage study between the susceptibility gene for affective disorder and tetranucleotide polymorphism of TH gene in five Japanese pedigrees. In addition to the linkage approach, we have undertaken an allelic association study using 74 patients with affective disorder and 78 controls with polymorphisms at the TH gene and the nearby dopamine D4 receptor gene. No evidence for linkage or associations were found. These results indicate that TH gene is less likely to contribute to the genetic component of affective disorders.

Adolescent↗
PubMed1995

Linkage studies on chromosome 22 in familial schizophrenia.

As part of a systematic search for a major genetic locus for schizophrenia we have examined chromosome 22 using 14 highly polymorphic markers in 23 disease pedigrees. The markers were distributed at an average distance of 6.6 cM, covering 70-80% of the chromosome. We analyzed the data by the lod score method using five plausible genetic models ranging from dominant to recessive, after testing the power of our sample under the same genetic parameters. The most positive lod score found was 1.51 under a recessive model for the marker D22S278, which is insufficient to conclude linkage. However, an excess of shared alleles in affected siblings (P < .01) was found for both D22S278 and D22S283. For D22S278, the A statistic was equal to the lod score (1.51) and therefore did not provide additional evidence for linkage allowing for heterogeneity, but the Liang statistic was more significant (P = .002). Our results suggest the possibility that the region around D22S278 and D22S283 contains a gene which contributes to the aetiology of schizophrenia.

Alleles↗
PubMed1995

Association of neurotrophin-3 gene variant with severe forms of schizophrenia.

The recent possible neurodevelopmental etiology of schizophrenia makes neurotrophin-3 (NT-3) gene an interesting candidate locus for molecular study of schizophrenia. We searched DNA variants through the coding region and the AP-1 binding site of the NT-3 gene, and found three variants. One is a missense mutation, Gly-63-->Glu-63 (GGG-->GAG), and the others are silent mutations. None of them have been associated with schizophrenia. However, a significant difference was found in the distribution of the variant, Gly-63-->Glu-63, between 61 patients and 101 controls, when the patients were restricted to severe cases based on the neurodevelopmental perspective. Individuals homozygous or heterozygous for the allele Glu-63 had a 2.595-fold increased risk of severe forms of schizophrenia.

Adolescent↗
PubMed1995

Early parental loss and depressive disorder in Japan.

The aim of this study is to determine in a Japanese sample whether or not the permanent loss of a parent by death or separation in childhood is aetiologically associated with unipolar major depressive disorder (according to RDC). We compared the incidence of parental loss before 17 years of age by death or separation between 122 depressed inpatients and 94 non- and never-depressed medical controls. Early maternal death was found to be significantly more common in the depressives than in the controls. Separation from either parent also showed a trend towards an increased incidence in the depressive group. No significant difference in the incidence of early paternal death was found.

Adolescent↗
PubMed1995

Genetic association of the very low density lipoprotein (VLDL) receptor gene with sporadic Alzheimer's disease.

A specific isoform of apolipoprotein E has been associated with the accelerated rate of disease expression of sporadic Alzheimer's disease (AD) and late-onset familial AD (FAD). An earlier age at onset has also been demonstrated in familial AD patients with mutations in the amyloid precursor protein (APP) gene (APP717 and APP670/671)13 carrying the APOE epsilon-4 allele compared to those who do not, but not in familial AD patients with APP692 or 693 mutations, or in chromosome 14-linked familial AD patients. Hypothesizing that receptors for apoE-containing lipoproteins act as a potential risk factor for AD, we performed an association study using a polymorphic triplet (CGG) repeat in the gene for the VLDL receptor (VLDL-R), a receptor for apoE-containing lipoproteins. The frequency of the 5-repeat allele was significantly higher in all of the Japanese sporadic AD patients (P < 0.02) than in the Japanese controls. Moreover, the odds ratio was significantly increased in the AD patients homozygous for the 5-repeat allele (OR = 2.1, 95% CI = [1.1-4.2]). Multiple logistic regression analysis reveals that the relative risk conferred by the presence of two copies of the 5-repeat allele and at least one copy of the APOE epsilon-4 allele is 8.7 (95% CI = [2.9-25.8]). Our results suggest that the VLDL-R gene is a susceptibility gene for AD.

Alleles↗
PubMed1995

Suggestive evidence for linkage of schizophrenia to markers on chromosome 13q14.1-q32.

Family, twin and adoption studies highlight the influence of genes in the aetiology of schizophrenia, though the mode of inheritance is unclear. We have been conducting a systematic search for major genes in schizophrenia using a series of multiply affected families and report preliminary results of linkage under heterogeneity with markers on chromosome 13. A lod2 score of 1.61 for marker D13S144 was obtained at theta = 0 and alpha of 0.5 and nearby markers also produced positive values.

Adoption↗
PubMed1995

Chromosome 22 markers demonstrate transmission disequilibrium with schizophrenia.

Previously we reported evidence for genetic linkage between markers on chromosome 22q12 and schizophrenia in 23 multiply affected pedigrees. As part of further investigation of this region, we have applied the transmission disequilibrium test (TDT) to the genotype data. The TDT is a test for both linkage and linkage disequilibrium, and is based on the unequal probability of transmission of two different marker alleles from parents to affected offspring. We obtained significant results for the marker D22S283 (chi 2 = 35.9, 14 df, p = 0.001), D22S278 (chi 2 = 16.5, 6 df, p = 0.01) and F8VWFP (chi 2 = 13.1, 4 df, p = 0.01). Application of the Bonferonni correction for testing multiple markers renders the results for marker D22S278 and F8VWFP non-significant (from p = 0.01 to p = 0.14), while the result for D22S283 remains modestly significant at p < 0.02. Overall, our findings strengthen the suggestion that the region around D22S283 contains a susceptibility gene for schizophrenia.

Chromosome Mapping↗
PubMed1995

Screening for mutations at codon 717 of the amyloid precursor protein gene in Alzheimer's disease.

Three kinds of missense mutation at codon 717 of amyloid precursor protein (APP) gene (Val --> Ile; Val --> Gly; Val --> Phe) were screened in 114 patients with familial and sporadic Alzheimer's disease (AD), using a rapid testing method for each Val --> Gly and Val --> Phe mutation and Goate's method for Val --> Ile mutation based on the polymerase chain reaction. Mutations were not found in the subjects, confirming earlier suggestions that these three mutations at codon 717 of APP gene account for only a small proportion of cases of not only familial AD but also sporadic AD.

Aged↗
PubMed1995

Schizophrenia following in utero exposure to the 1957 influenza epidemics in Japan.

OBJECTIVE: Studies in Finland, England, and Denmark have reported that individuals exposed to the 1957 A2 influenza pandemic during their second trimester in utero are at greater risk for later schizophrenia. However, other studies in England, the United States, and Holland reported no such association. The authors' goal was to shed light on these conflicts. METHOD: They compared the number of individuals who later developed schizophrenia who were born in the 5 months after the peak prevalence of three distinct 1957 influenza epidemics in Japan with the mean number of individuals who later developed schizophrenia who were born in the corresponding months of the 4 years surrounding the epidemics. RESULTS: A significantly greater number of females but not males who later developed schizophrenia were born during the risk exposure months than in the non-risk-exposure months. CONCLUSIONS: These findings, although weak, lend support to the claim that in utero exposure to influenza epidemics is a risk factor for adult schizophrenia.

Adult↗
PubMed1994

No allelic association between Parkinson's disease and dopamine D2, D3, and D4 receptor gene polymorphisms.

Parkinson's disease is thought to be caused by a combination of unknown environmental, genetic, and degenerative factors. Evidence from necropsy brain samples and pharmacokinetics suggests involvement of dopamine receptors in the pathogenesis or pathophysiology of Parkinson's disease. Genetic association studies between Parkinson's disease and dopamine D2, D3 and D4 receptor gene polymorphisms were conducted. The polymorphism was examined in 71 patients with Parkinson's disease and 90 controls. There were no significant differences between two groups in allele frequencies at the D2, D3, and D4 dopamine receptor loci. Our findings do not support the hypothesis that susceptibility to Parkinson's disease is associated with the dopamine receptor polymorphisms examined.

Adult↗
PubMed1994

No evidence of linkage or allelic association of schizophrenia with DNA markers at pericentric region of chromosome 9.

Based on our previous study suggesting the pericentric region of chromosome 9 as of potential importance in schizophrenia, we have carried out a linkage study between the schizophrenia phenotype and the dinucleotide repeat polymorphisms D9S55, D9S15, and D9S202 in three pedigrees multiply affected with schizophrenia. In addition, we have conducted allelic association studies using 60 patients with schizophrenia and 60 controls with polymorphisms at D9S55 and D9S15 markers. No evidence for linkage or association was found. The results indicate that susceptibility genes for schizophrenia are less likely to be located at the pericentric region of chromosome 9, assuming genetic homogeneity of the pedigrees.

Alleles↗
PubMed1994

Further evidence of no linkage between schizophrenia and the dopamine D3 receptor gene locus.

The dopamine hypothesis of schizophrenia proposed that dopaminergic pathways are involved in the etiology of the disease. In particular, interest among psychiatrists has focused on the D2 receptor because of its affinity to antipsychotic drugs. Recently a new dopamine receptor gene has been cloned, and named the dopamine D3 receptor. The D3 receptor is a potential site for antipsychotic drug action and may be involved in the pathophysiology of schizophrenia. We have carried out a linkage study between the susceptibility gene for schizophrenia and polymorphism of the dopamine D3 receptor gene in two Japanese pedigrees. The LOD scores were negative for all genetic models and for all affective status at a recombination fraction theta = 0. Linkage of DRD3 has been excluded for the model 1 (dominant model) and the model 3 (recessive model). The LOD score was -3.43 at theta = 0 for model 1 (dominant model) and broad definition of affected status. These results were consistent with previous studies.

DNA↗
PubMed1994

Mismatch PCR RFLP detection of DRD2 Ser311Cys polymorphism and schizophrenia.

We tested 100 schizophrenics and 100 controls to find association at the Serine311 Cysteine polymorphism of dopamine D2 receptor in Japanese population. There were no significant differences between the two groups. One homozygote for Cys311 was confirmed in the controls by mismatch-polymerase chain reaction and restriction fragment length of polymorphism (PCR-RFLP) analysis. None with Cys was detected among 61 individuals of nine multiply affected families with schizophrenia. Our data thus provide strong evidence against an etiological association between schizophrenia and the Ser311Cys variant. The polymerase chain reaction amplification of specific alleles (PASA) analysis was compared with the mismatch PCR-RFLP typing, revealing that the latter is more reliable than the former.

Alleles↗
PubMed1994

Association of apolipoprotein E4 with sporadic Alzheimer's disease is more pronounced in early onset type.

Apolipoprotein E genotypes in 88 unrelated Japanese patients with NINCDS-ADRDA sporadic Alzheimer's disease (AD) were examined and compared with those of 93 healthy controls. Frequency of epsilon 4 allele was increased in patients with AD (31%) compared with controls (10%), as was reported previously. Individuals homozygous or heterozygous for the allele epsilon 4 had a 5.9-fold increased risk of AD. This tendency was more pronounced in early onset sporadic (= non-familial) type than late onset type. The relative risk was also greater for early onset type (RR = 11.7; 95% CI, 4.9-28.3) than late onset type (RR = 4.3; 95% CI, 2.1-8.8). Moreover, patients with homozygote for the allele epsilon 4 had a 14.7-fold increased risk of early onset sporadic AD (P < 0.005, chi 2 = 9.0, df = 1, 95% CI, 2.5-85.1). Our findings indicated that association of apolipoprotein epsilon 4 with sporadic Alzheimer's disease is more pronounced in early onset type than in late onset type.

Age of Onset↗