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M Virkkunen

Publications and source records attributed to M Virkkunen.

At least 37 records · Page 2Linked to original sources
PubMed1999

Cladistic association analysis of Y chromosome effects on alcohol dependence and related personality traits.

Association between Y chromosome haplotype variation and alcohol dependence and related personality traits was investigated in a large sample of psychiatrically diagnosed Finnish males. Haplotypes were constructed for 359 individuals using alleles at eight loci (seven microsatellite loci and a nucleotide substitution in the DYZ3 alphoid satellite locus). A cladogram linking the 102 observed haplotype configurations was constructed by using parsimony with a single-step mutation model. Then, a series of contingency tables nested according to the cladogram hierarchy were used to test for association between Y haplotype and alcohol dependence. Finally, using only alcohol-dependent subjects, we tested for association between Y haplotype and personality variables postulated to define subtypes of alcoholism-antisocial personality disorder, novelty seeking, harm avoidance, and reward dependence. Significant association with alcohol dependence was observed at three Y haplotype clades, with significance levels of P = 0.002, P = 0.020, and P = 0.010. Within alcohol-dependent subjects, no relationship was revealed between Y haplotype and antisocial personality disorder, novelty seeking, harm avoidance, or reward dependence. These results demonstrate, by using a fully objective association design, that differences among Y chromosomes contribute to variation in vulnerability to alcohol dependence. However, they do not demonstrate an association between Y haplotype and the personality variables thought to underlie the subtypes of alcoholism.

Alcoholism↗
PubMed1999

No coding variant of the tryptophan hydroxylase gene detected in seasonal affective disorder, obsessive-compulsive disorder, anorexia nervosa, and alcoholism.

BACKGROUND: The goal of this study was to evaluate the role of genetic variation in the coding sequence of tryptophan hydroxylase (TPH) in the pathogenesis of several psychiatric diseases in which altered serotonin function has been implicated: bipolar affective disorder (BP), obsessive-compulsive disorder (OCD), anorexia nervosa (AN), seasonal affective disorder (SAD), panic disorder (PD), and alcoholism (Alc). METHODS: Ninety-three percent of the TPH coding sequence was screened by polymerase chain reaction single-strand conformation polymorphism (SSCP) for DNA sequence variations in 128 AN, 88 OCD, 72 SAD, 45 PD, and 36 BP patients and 142 normal volunteers. Also included in the screening were 61 Alc randomly selected from a Finnish alcoholic population in which an association of a TPH intron 7 polymorphism with suicidality was previously observed. Polymorphisms detected by SSCP were characterized by DNA sequencing and by allele-specific restriction enzyme digestion. Genotyping was then performed in 34 Finnish alcoholic suicide attempters. RESULTS: A rare silent mutation was identified in exon 10 and is designated T1095C. The C1095 allele was found in 1 OCD and in 2 AN subjects; all 3 individuals were heterozygous (C1095/T1095) for the variant allele. No association was observed between this TPH T1095C variant with either OCD, AN, Alc, or suicidality. CONCLUSION: These results suggest that the coding sequence of the TPH gene does not contain abundant variants, and may not play a major role in vulnerability to several psychopathologies in which reduced serotonin turnover has been implicated.

Alcoholism↗
PubMed1999

Autosomal, mitochondrial, and Y chromosome DNA variation in Finland: evidence for a male-specific bottleneck.

The high prevalence of rare genetic diseases in Finland has been attributed to a founder effect some 2,000 years ago. However, this hypothesis has not been supported from mtDNA sequence and autosomal microsatellite data which indicate high levels of gene diversity. Here we have identified genetic evidence for a population bottleneck by examining variable microsatellite loci on the nonrecombining portion of Y chromosomes from Finland and four populations from Europe and the Americas. Sequence data from segment I of the control region (HVS-1) of mtDNA (360 bases) and 20 autosomal dinucleotide repeat markers were also analyzed. Partitions of genetic variance within and between populations revealed significant levels of Y-chromosome differentiation between populations. Phylogenetic and diversity analyses revealed divergent Finnish Y-haplotype clades and significantly lower Y-haplotype diversity among Finns as compared to other populations. Surprisingly, Finnish Y-haplotype diversity was even lower than the Native American populations. These results provide support for the Finnish bottleneck hypothesis. Evidence for two separate founding Finnish Y-chromosome lineages was also observed from the Y-chromosome phylogeny. A limited number of closely related founding males may have contributed to the low number of paternal lineages in the Finnish population. In contrast, high levels of genetic diversity for mtDNA and autosomal STRs may be the result of sex-biased gene flow and recent immigration to urban areas from established internal isolates within Finland.

Base Sequence↗
PubMed1999

Identification of four variants in the tryptophan hydroxylase promoter and association to behavior.

One of the most replicated findings in biological psychiatry is the observation of lower 5-hydroxyindoleacetic acid concentrations, the major metabolite of serotonin, in the brain and cerebrospinal fluid of subjects with impulsive aggression. Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the synthesis of serotonin, however functional variants have not been reported from the coding sequence of this gene. Therefore, we screened the human TPH promoter (TPH-P) for genetic variants which could modulate TPH gene transcription. The TPH-P (2093 nucleotides) was screened for sequence variation by SSCP analysis of 260 individuals from Finnish, Italian, American Caucasian, and American Indian populations. Four common polymorphisms were identified: -7180T>G, -7065C>T, -6526A>G, and -5806G>T (designated as nucleotides upstream of the translation start site). In the Finns, the four polymorphisms had a minor allele frequency of 0.40 and in this population linkage disequilibrium between the four loci was complete. In the other populations the minor allele frequencies ranged from 0.40 to 0.45. TPH -6526A>G genotype was determined in 167 unrelated Finnish offenders and 153 controls previously studied for the TPH IVS7+779C>A polymorphism. A significant association was observed between -6526A>G and suicidality in the offenders. TPH -6526A>G and the previously reported intron seven polymorphism, TPH IVS7+779C>A, exhibited a normalised linkage disequilibrium of 0.89 in Finns. Normalized linkage disequilibrium was reduced in other populations, being 0.49 and 0.21 in Italians and American Indians, respectively. In conclusion, four TPH-P variants were identified which can be used for haplotype-based analysis to localize functional TPH alleles influencing behavior.

Adult↗
PubMed1998

Identification of a naturally occurring Pro15-Ser15 substitution in the serotonin5A receptor gene in alcoholics and healthy volunteers.

We screened the serotonin5A receptor gene coding region in 186 unrelated alcoholic patients and 187 controls. A relatively abundant amino acid substitution and two synonymous DNA substitutions were detected. Two synonymous variants, A12T and C789T, had rarer-allele frequencies of 23% and 1%, respectively. The Pro15Ser substitution is located in the amino terminal, extracellular domain of the receptor adjacent to a putative phosphorylation site. Pro15Ser had rarer-allele frequencies of 8.1% and 5.9% in Finnish alcoholic patients and controls, respectively (p=n.s.).

Alcoholism↗
PubMed1998

Mutation screening of the 5-hydroxytryptamine7 receptor gene among Finnish alcoholics and controls.

Impaired central serotonin neurotransmission has been associated with increased aggression, impaired impulse control and diurnal activity rhythm disturbances among humans. Neuroanatomic distribution and pharmacological properties of the serotonin 5-HT7 receptor suggest that it may play a role in psychiatric disorders and in circadian rhythm regulation. In this study a point mutation causing proline279 --> leucine amino acid substitution in the 5-hydroxytryptamine7 (5-HT7) receptor gene was discovered. This 5-HT7Leu279 variant was observed in six of 825 individuals, all of whom are heterozygous for the substitution. Three of them are alcoholic offenders (3/255), two are relatives of an offender without the 5-HT7Leu279 allele (2/255) and one is a healthy control without any psychiatric diagnosis (1/248). The allele frequency of the 5-HT7Leu279 variant is 0.004 (6/758) among Finns. Although the 5-HT7Leu279 variant is approximately three times more common among alcoholic offenders than among healthy controls, it is not significantly associated with alcoholism or impulsivity in the present study. The 5-HT7Leu279 allele may, however, be a predisposing allele in a subgroup of alcoholic offenders with multiple behavioral problems.

Adult↗
PubMed1998

Role of the serotonin transporter promoter polymorphism in anxiety-related traits.

BACKGROUND: The heritability of interindividual variation in anxiety and other aspects of personality establishes that variants of genes influence these traits. A functional polymorphism in the promoter of the human serotonin transporter gene (SLC6A4*C) was identified and found to be linked to an anxiety-related personality trait, Neuroticism. The polymorphism affects gene transcription and, ultimately, gene function. We have attempted to confirm the role of SLC6A4*C in anxiety-related personality traits by sibpair analysis and association studies. METHODS: Sibpair linkage analysis and association study were performed in 655 Finns. The index cases were 182 alcoholic criminal offenders, through which 258 relatives were ascertained to obtain 366 sibpairs. In addition, 215 unrelated population controls were collected. Each individual was psychiatrically interviewed, blind-rated for DSM-III-R diagnoses, and assessed with the Tridimensional Personality Questionnaire. RESULTS: The sibpair analysis revealed a positive linkage between SLC6A4*C and the 2 anxiety-related subdimensions of Harm Avoidance: HA1 (Anticipatory Worry) and HA2 (Fear of Uncertainty) (P = .003). However, there was no consistent association between SLC6A4*C and any Tridimensional Personality Questionnaire trait. CONCLUSIONS: In the present study we replicated the relationship of SLC6A4*C to anxiety by sibpair linkage analysis but found no evidence of association, raising the question of whether SLC6A4*C locus is itself affecting anxiety or is linked to another still unknown functional variant.

Alcoholism↗
PubMed1998

Linkage of antisocial alcoholism to the serotonin 5-HT1B receptor gene in 2 populations.

BACKGROUND: In mice, quantitative trait locus studies and behavioral evaluation of animals deleted for 5-HT1B have implicated this serotonin autoreceptor in alcohol consumption and aggressive behavior. We therefore investigated whether the 5-HT1B gene (HTR1B) is linked to alcoholism with aggressive and impulsive behavior in the human, as represented by 2 psychiatric diagnoses: antisocial personality disorder and intermittent explosive disorder comorbid with alcoholism. METHODS: Linkage was first tested in 640 Finnish subjects, including 166 alcoholic criminal offenders, 261 relatives, and 213 healthy controls. This was followed by a study in a large multigenerational family derived from a Southwestern American Indian tribe (n=418) with a high rate of alcoholism. All subjects were psychiatrically interviewed, blind-rated for psychiatric diagnoses, and typed for a HTR1B G861C polymorphism and for a closely linked short-tandem repeat locus, D6S284. Linkage was evaluated in sib pairs, and by using an association approach in which pedigree randomization corrects for nonindependence of observations on related subjects. RESULTS: In Finnish sib pairs, antisocial alcoholism showed significant evidence of linkage to HTR1B G861C (P=.04) and weak evidence with D6S284 (P=.06). By association analysis, the 183 Finnish antisocial alcoholics had a significantly higher HTR1B-861C allele frequency than the other 457 Finns we studied (P=.005). In the Southwestern American Indian tribe, significant sib pair linkage of antisocial alcoholism to HTR1B G861C (P=.01) was again observed, and there was also significant linkage to D6S284 (P=.01). CONCLUSION: These results suggest that a locus predisposing to antisocial alcoholism may be linked to HTR1B at 6q13-15.

Adolescent↗
PubMed1998

A tryptophan hydroxylase gene marker for suicidality and alcoholism.

BACKGROUND: Tryptophan hydroxylase (TPH) is the rate-limiting enzyme in the synthesis of serotonin. Low turnover rate of this monoamine neurotransmitter is associated with impaired impulse control. We previously reported that, in Finns, TPH genotype was associated with suicidality, a pathophysiological mechanism that may involve impaired impulse control. METHODS: Association and sib-pair linkage analyses of a polymorphism in intron 7 of the TPH gene with suicidality, alcoholism, and the Karolinska Scales of Personality were conducted in 804 Finnish alcoholic offenders, controls, and their relatives, in a sample that included 369 sib pairs. RESULTS: The association of the TPH 17 779C (L) allele to suicidality in impulsive offenders reported previously was replicated in a new group of Finnish offenders (P=.001, n=122). The intron 7 variant in the TPH gene showed significant evidence for linkage to suicidality (P=.006 in unaffected sib pairs), severe suicide attempts (P=.006 in unaffected sib pairs; regression: P=.01), alcoholism (P=.003 in unaffected sib-pairs; regression: P=.02), and Karolinska Scales of Personality socialization score (regression: P=.002). CONCLUSIONS: The status of the TPH A779C allele as a marker for suicidality was replicated and linkage with alcoholism and Karolinska Scales of Personality socialization score was also observed. A functional variant(s) in or close to the TPH gene may predispose individuals to suicidality and other behaviors thought to be influenced by serotonin.

Adult↗
PubMed1998

Dual origins of Finns revealed by Y chromosome haplotype variation.

The Finnish population has often been viewed as an isolate founded 2, 000 years ago via a route across the Gulf of Finland. The founding event has been characterized as involving a limited number of homogeneous founders, isolation, and subsequent rapid population growth. Despite the purported isolation of the population, levels of gene diversity for the Finns at autosomal and mitochondrial DNA loci are indistinguishable from those of other Europeans. Thus, mixed or dual origins for the Finns have been proposed. Here we present genetic evidence for the dual origins of Finns by evaluating the pattern of Y chromosome variation in 280 unrelated males from nine Finnish provinces. Phylogenetic analysis of 77 haplotype configurations revealed two major star-shaped clusters of Y haplotypes, indicative of a population expansion from two common Y haplotypes. Dramatic and quite significant differences in Y haplotype variation were observed between eastern and western regions of Finland, revealing contributions from different paternal types. The geographic distribution and time of expansion for the two common Y haplotypes correlate well with archeological evidence for two culturally and geographically distinct groups of settlers. Also, a northeastern to southwestern gradient of Y haplotype frequencies provides convincing evidence for recent male migration from rural areas into urban Finland.

Evolution, Molecular↗
PubMed1998

Fluoxetine normalizes increased cardiac vagal tone in bulimia nervosa.

Patients with bulimia nervosa have been reported to respond to treatment with the serotonin uptake inhibitor fluoxetine. In a preliminary study, which had a small sample size, women with bulimia nervosa were reported to have elevated cardiac vagal tone. We investigated cardiac vagal tone in women with bulimia nervosa before and after treatment with fluoxetine. At baseline, resting cardiac vagal tone, deduced from the respiratory component of heart rate variability, was quantified in 41 healthy volunteer women and in 25 women with bulimia nervosa. The bulimic women received in a parallel-group design, double blind, either placebo or fluoxetine 60 mg/24 hr for 8 weeks. All patients participated in behavioral therapy. Resting cardiac vagal tone was measured again at the end of the treatment. Women with bulimia nervosa had higher cardiac vagal tone than age-matched healthy volunteer women. Placebo had no effect on cardiac vagal tone. Fluoxetine reduced cardiac vagal tone among the women with bulimia nervosa to a level similar to the healthy volunteer women. Women with bulimia nervosa have elevated resting cardiac vagal tone. Fluoxetine normalized the elevated resting cardiac vagal tone among the women with bulimia nervosa. At both the central and peripheral levels, vagal neurons are endowed with serotonin-3 receptors. In vitro, fluoxetine desensitizes or blocks serotonin-3 receptors. A controlled trial of serotonin-3 receptor blockers is warranted in bulimia nervosa.

Adult↗
PubMed1997

Serotonin in early-onset alcoholism.

This chapter examines current, common schemes to subgroup alcoholics to arrive at relatively homogeneous groups of patients to facilitate psychobiological and molecular genetic studies. Early-onset, male-limited alcoholism is commonly associated with antisocial personality disorder or antisocial behavioral traits. It is often preceded by early-onset aggressiveness, which is followed by conduct disorder. Early-onset alcoholism among men is associated with low central serotonin turnover rate. The data concerning platelet MAO activity and serotonin uptake to platelets among early-onset alcoholics are conflicting. Recent molecular genetic and brain imaging studies on early-onset alcoholics are preliminary but appear very promising.

Aggression↗
PubMed1997

Suicidal behavior among Finnish fire setters.

Histories of serious suicide attempts and slashing were investigated among Finnish fire setters. Medical and criminal records of 304 fire setters were examined to compare those who had attempted suicide with those who had not, and those who had slashed themselves with those who had not using biological, diagnostic, and demographic variables. Major mood disorders, father's alcoholism, and suicidal motive of fire setting (self-immolation) were significantly associated with suicide attempts. Paternal violent alcoholism, father's criminality, and suicidal motive of fire setting were significantly associated with slashing. Among fire setters, non-lethal slashing is a predictor of serious suicidality. Associations between psychiatric diagnoses, family history, and suicidality among fire setters are similar to those reported for suicidal patients with mood and substance abuse diagnoses. Therefore, studying fire setters, who exhibit an extremely high incidence of suicidal behavior, is an effective way to elucidate psychobiology of suicidal behaviors.

Adolescent↗
PubMed1997

Criminal and psychiatric histories of Finnish arsonists.

We investigated psychiatric and demographic variables and lifetime criminality among arsonists referred for a pre-trial psychiatric assessment. The medical and criminal records of 282 arsonists were studied in order to compare first-time and repeat offenders with regard to diagnostic, demographic and biological variables. Alcohol dependence and antisocial personality disorder were common among recidivist offenders. This finding was especially prominent among offenders who committed violent crimes. Recidivist offenders commonly had a history of long-lasting enuresis during their childhood. They were younger at the time of their first offence, and were more often intoxicated with alcohol during the arson attempt. Among arsonists, lifetime criminal recidivism was primarily associated with alcohol dependence and antisocial personality disorder. Psychosis was a common diagnosis among subjects who had no record of recidivist criminal offences.

Adult↗
PubMed1997

Criminal recidivism and family histories of schizophrenic and nonschizophrenic fire setters: comorbid alcohol dependence in schizophrenic fire setters.

Life-time criminality, family history, and situational factors during a fire-setting offense were compared between 44 fire setters who had been diagnosed with schizophrenia or delusional psychosis and 260 nonpsychotic fire setters who had undergone a pretrial forensic psychiatric evaluation. The same comparisons were made between alcoholic (n = 25) and nonalcoholic (n = 19) schizophrenic fire setters. Medical and criminal records were studied. Life-time criminal histories of schizophrenic and nonschizophrenic fire setters were not significantly different with respect to multiple fire setting and violent offenses. Nonschizophrenic and alcoholic schizophrenic fire setters had, in general, a high rate of criminal offenses. The family history of schizophrenic fire setters was often characterized by the father's alcoholism and the mother's psychosis. Comorbid familial alcoholism increased life-time criminal recidivism among schizophrenic fire setters.

Adult↗
PubMed1996

A prospective follow-up study of alcoholic violent offenders and fire setters.

BACKGROUND: This study investigated biochemical and family variables and predictors of recidivism among forensic psychiatric patients who had committed violent offenses or set fires. METHODS: One hundred fourteen male alcoholic violent offenders and fire setters were followed up for an average of 4.5 years after release from prison. At the beginning of their incarceration, the first half of the offenders were administered clinical diagnostic interviews, whereas the latter half received the Structured Clinical Interview for DSM-III (SCID) that was blind rated. A structured family history questionnaire was administered to all available first-degree relatives of offenders. The offenders also received lumbar punctures for monoamine metabolites, an oral glucose tolerance test, and a measurement of fasting plasma cholesterol level. At the end of the follow-up, the Finnish criminal registry was searched for recidivist crimes. RESULTS: Among all offenders, low cerebrospinal fluid (CSF) 5-hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) concentrations were associated with a family history positive for paternal alcoholism with violence. Low plasma cholesterol concentration was associated with a family history positive for paternal alcoholism without violence. The recidivists, who committed violent offenses or set fires during the follow-up period, had low CSF 5-HIAA and 3-methoxy-4-hydroxyphenylglycol (MHPG) concentrations compared with those in nonrecidivists. Early family environments of the recidivists, compared with those of the nonrecidivists, were characterized by common paternal absence from and presence of brothers at home. CONCLUSION: Among male alcoholic violent offenders and fire setters, low CSF 5-HIAA and HVA concentrations are strongly associated with a family history positive for paternal violence and alcoholism, while low fasting plasma cholesterol concentration is associated with a family history positive for paternal alcoholism. Recidivist violent offenders and fire setters are predicted by low CSF 5-HIAA and MHPG concentrations and a developmental history positive for early paternal absence from and presence of brothers in the family of origin.

Adult↗
PubMed1996

Serotonin in alcoholic violent offenders.

Finnish alcoholic, impulsive, habitually violent offenders have been found to have low brain serotonin (5-hydroxytryptamine; 5-HT) turnover which is associated with impaired impulse control, a history of suicide attempts, hypoglycaemic tendency after an oral glucose load and diurnal activity rhythm dysregulation or hyperactivity. Relatively high cerebrospinal fluid (CSF) free testosterone concentration is a further characteristic of the offenders with antisocial personality disorder. The impulsive offenders may represent a behaviourally extreme group of type 2 alcoholics as defined by Cloninger. A large cohort of 800 subjects, including alcoholic violent offenders, their relatives and male controls, has now been gathered from Finland with support from the National Institute on Alcohol Abuse and Alcoholism. About 200 subjects have provided CSF samples. Leukocytes from the whole cohort have been harvested and immortalized. Genes regulating 5-HT functions are now being systematically analysed from these samples. Thus far, polymorphisms of the tryptophan hydroxylase (TPH) and 5-HT2C receptor genes have been the most informative findings.

Alcoholism↗