Ketone body 3-hydroxybutyrate as a biomarker of aggression.

Human aggression is a complex behaviour, the biological underpinnings of which remain poorly known. To gain insights into aggression biology, we studied relationships with aggression of 11 low-molecular-weight metabolites (amino acids, ketone bodies), processed using 1H nuclear magnetic resonance spectroscopy. We used a discovery sample of young adults and an independent adult replication sample. We studied 725 young adults from a population-based Finnish twin cohort born 1983-1987, with aggression levels rated in adolescence (ages 12, 14, 17) by multiple raters and blood plasma samples at age 22. Linear regression models specified metabolites as the response variable and aggression ratings as predictor variables, and included several potential confounders. All metabolites showed low correlations with aggression, with only one-3-hydroxybutyrate, a ketone body produced during fasting-showing significant (negative) associations with aggression. Effect sizes for different raters were generally similar in magnitude, while teacher-rated (age 12) and self-rated (age 14) aggression were both significant predictors of 3-hydroxybutyrate in multi-rater models. In an independent replication sample of 960 adults from the Netherlands Twin Register, higher aggression (self-rated) was also related to lower levels of 3-hydroxybutyrate. These exploratory epidemiologic results warrant further studies on the role of ketone metabolism in aggression.

Genetic and environmental influences on non-specific neck pain in early adolescence: a classical twin study.

BACKGROUND: Prevalence of neck pain has increased among adolescents. The origins of adult chronic neck pain may lie in late childhood, but for early prevention, more information is needed about its aetiology. We investigated the relative roles of genetic and environmental factors in early adolescent neck pain with a classic twin study. METHODS: Frequency of neck pain was assessed with a validated pain questionnaire in a population-based sample of nearly 1800 pairs of 11-12-year-old Finnish twins. Twin pair similarity for neck pain was quantified by polychoric correlations, and variance components were estimated with biometric structural equation modelling. RESULTS: Prevalence of neck pain reported at least once monthly was 38% and at least once weekly 16%, with no significant differences between gender and zygosity. A greater polychoric correlation in liability to neck pain was found in monozygotic (0.67) than for dizygotic pairs (0.38), suggesting strong genetic influences. Model fitting indicated that 68% (95% confidence interval 62-74) of the variation in liability to neck pain could be attributed to genetic effects, with the remainder attributed to unshared environmental effects. No evidence for sex-specific genetic effects or for sex differences in the magnitude of genetic effects was found. CONCLUSIONS: Genetic and unique environmental factors seem to play the most important roles in liability to neck pain in early adolescence. Future research should be directed to identifying pathways for genetic influences on neck pain and in exploring effectiveness of interventions that target already identified environmental risk factors.

Prospective relationships of ADHD symptoms with developing substance use in a population-derived sample.

BACKGROUND: Clinically ascertained reports suggest that boys and girls with attention deficit hyperactivity disorder (ADHD) may differ from each other in their vulnerability to substance use problems. METHOD: A total of 1545 Finnish adolescents were assessed for DSM-IV-based ADHD symptoms by their parents and classroom teachers using standardized rating scales at age 11-12 years. At age 14, substance use disorders and psychiatric co-morbidity were assessed with the Semi-Structured Assessment for the Genetics of Alcoholism, providing DSM-III-R/DSM-IV diagnoses for Axis I disorders. At age 17.5, substance use was assessed by multi-item questionnaire. RESULTS: Although baseline ADHD symptoms were less common among females, they were more predictive of adverse substance use outcomes once conduct disorder and previous substance use were controlled for. Only in females were baseline ADHD symptoms significant predictors of alcohol abuse and dependence and illicit drug use at age 14. At the age of 17.5, parents' reports of inattentiveness and hyperactivity were significant predictors for frequent alcohol use in both sexes, but they were more predictive of frequent alcohol and illicit drug use in girls. Impulsivity in teachers' ratings predicted frequent alcohol use and illicit drug use in boys. Parental reports of inattentiveness in their 11-/12-year-old daughters were a consistent predictor for illicit drug use across adolescence. CONCLUSIONS: Inattentiveness and hyperactivity may be more predictive of alcohol use disorders and maladaptive patterns of alcohol and illicit drug use among girls than boys. The importance of these behavioural symptoms should be assessed further in the community, as they could jeopardize adolescents' successful transitioning into adult roles.

Microfibrillar-associated protein 5 is linked with markers of obesity-related extracellular matrix remodeling and inflammation.

OBJECTIVE: Microfibrillar-associated protein 5 (MFAP5) is an extracellular matrix (ECM) glycoprotein, which is colocalized with microfibrils in elastin networks. Its function in adipose tissue (AT) is not known. We have recently shown that the expression of MFAP5 is downregulated in AT along with weight reduction (WR) in persons with metabolic syndrome (MetS). The aim of this work was to study whether the change of MFAP5 mRNA expression in response to WR is associated with markers of adiposity, glucose metabolism and insulin resistance in human AT. DESIGN: Weight reduction intervention study in parallel study design (The Genobin study). Altogether 46 obese subjects with impaired glucose tolerance and features of MetS were randomized to a WR (n=28) or a control group (n=18) lasting for 33 weeks. MEASUREMENTS: Circulating glucose and insulin concentrations were measured and subcutaneous AT biopsies were performed before and after the intervention. The mRNA expression was studied by quantitative real-time PCR (QPCR). RESULTS: QPCR of human AT biopsy samples confirmed that MFAP5 is highly expressed in AT and its expression is decreased during WR. The mRNA expression of MFAP5 correlated positively with body mass index, and the change in MFAP5 mRNA expression during WR correlated positively with the change of body fat mass. Furthermore, the MFAP5 mRNA expression correlated negatively with circulating fasting concentrations of adiponectin and interleukin (IL)-1ß and positively with leptin, insulin and IL-1Ra levels. In addition, the MFAP5 mRNA expression correlated positively with the mRNA expressions of peroxisome proliferator-activated receptor gamma, cyclin D2 and A disintegrin and metalloproteinase domain 12, genes involved in AT remodeling. CONCLUSION: This study demonstrates that MFAP5 is highly expressed in human AT and is correlated with markers of insulin resistance. Furthermore, it is possible that MFAP5 is related to ECM remodeling during development of obesity.

Link between plasma ceramides, inflammation and insulin resistance: association with serum IL-6 concentration in patients with coronary heart disease.

AIMS/HYPOTHESIS: Ceramides and IL-6 have a role in immune-inflammatory responses and cardiovascular diseases, and are suggested to be involved in insulin and glucose metabolism. We sought to assess the associations of circulating levels of IL-6, TNF-alpha and high-sensitivity C reactive protein (hsCRP), which are inflammatory markers related to insulin resistance (IR), with the plasma lipid metabolites ceramides and diacylglycerols (DAG) in patients with CHD. METHODS: Cross-sectional analyses were carried out on data from 33 patients with CHD. Serum levels of the inflammatory markers and plasma lipid metabolites (lipidomics approach performed by ultra-performance liquid chromatography coupled to electrospray ionisation MS) were measured at the same time point as insulin resistance (IR) (HOMA-IR index). RESULTS: Serum circulating levels of IL-6 were strongly correlated with plasma ceramide concentrations (r = 0.59, p < 0.001). Adjustments for serum TNF-alpha or hsCRP levels, smoking, BMI, age, sex or HOMA-IR did not change the results (p < 0.001). After adjustments for the effect of serum inflammatory markers (TNF-alpha or hsCRP), HOMA-IR and BMI the correlation between plasma DAG and serum IL-6 (r = 0.33) was also significant (p < 0.03). In a linear regression model, circulating levels of both ceramides and TNF-alpha had a significant independent influence on circulating levels of IL-6, altogether accounting for 41% of its variation (p < 0.001). CONCLUSIONS/INTERPRETATION: Our results strongly suggest that the link between ceramides, IR and inflammation is related to the inflammatory marker IL-6. Ceramides may contribute to the induction of inflammation involved in IR states that frequently coexist with CHD.

Genetic and environmental effects on body mass index during adolescence: a prospective study among Finnish twins.

OBJECTIVE: To study genetic and environmental factors affecting body mass index (BMI) and BMI phenotypic correlations across adolescence. DESIGN: Prospective, population-based, twin cohort study. PARTICIPANTS AND METHODS: We used twin modeling in 2413 monozygotic and same-sex and opposite-sex dizygotic Finnish twin pairs born in 1983-1987 and assessed using self-report questionnaires at 11-12, 14 and 17 years of age. RESULTS: Heritability of BMI was estimated to be 0.58-0.69 among 11-12- and 14-year-old boys and girls, 0.83 among 17-year-old boys and 0.74 among 17-year-old girls. Common environmental effects shared by siblings were 0.15-0.24 among 11-12- and 14-year-old boys and girls but no longer discernible at 17 years of age. Unique environmental effects were 0.15-0.23. Additive genetic factors explained 90-96% of the BMI phenotypic correlations across adolescence, whereas unique environmental factors explained the rest. Common environment had no effect on BMI phenotypic correlations. CONCLUSIONS: The genetic contribution to BMI is strong during adolescence, and it mainly explains BMI phenotypic correlations across adolescence. Common environmental factors have an effect on BMI during early adolescence, but that effect disappears by late adolescence.

Association of sequence variations in the gene encoding insulin-like growth factor binding protein 5 with adiponectin.

BACKGROUND: Insulin-like growth factor binding protein 5 (IGFBP5) binds to IGF and thus modulates IGF signaling pathway. We have shown earlier that the IGFBP5 gene was downregulated in the adipose tissue after 12-week carbohydrate diet with low insulinemic response. OBJECTIVE: The aim was to examine the putative contribution of genetic variation of the IGFBP5 gene to the characteristics of metabolic syndrome and incidence of type 2 diabetes (T2DM) in the Finnish Diabetes Prevention Study (DPS). METHODS: DPS is a longitudinal study where 522 subjects with impaired glucose tolerance were randomized to either lifestyle intervention group or control group. DNA was available from 507 subjects (mean body mass index (BMI) 31.2+/-4.5 kg/m(2), age 55+/-7 years). The eight single-nucleotide polymorphisms (SNPs) were selected from HapMap database and genotyped by Taqman allelic discrimination protocol. The main results were confirmed in a larger cross-sectional study population (METSIM). In addition, the gene expression of IGFBP5 was studied in two previously published study populations (FUNGENUT and GENOBIN) of 124 subjects with insulin resistance (BMI 32.2+/-3.5 kg/m(2), age 57.7+/-7.4 years). RESULTS: Three out of eight IGFBP5 markers (rs9341234, rs3276 and rs11575134) were significantly associated with circulating adiponectin concentrations in men. Furthermore, mRNA expression studies of subcutaneous adipose tissue showed that mRNA concentrations of IGFBP5 correlated with adiponectin concentrations in all subjects and in women. None of the IGFBP5 SNPs were associated with T2DM. CONCLUSIONS: Our findings show that IGFBP5 has a gender-specific association with adiponectin, which may modulate the development of metabolic syndrome.

The genetic variation in the tenomodulin gene is associated with serum total and LDL cholesterol in a body size-dependent manner.

We have reported that the sequence variation in the tenomodulin (TNMD) gene is associated with the risk of type 2 diabetes (T2DM), central obesity and serum levels of systemic immune mediators in the Finnish Diabetes Prevention Study (DPS), which is a longitudinal lifestyle intervention study on 522 middle-aged persons with impaired glucose tolerance (IGT). The aim of this study was to investigate whether the association with T2DM, observed in the DPS could be replicated in a larger, cross-sectional population-based random sample of 5298 men (3020 with normoglycaemia, 984 with impaired fasting glucose, 436 with IGT and 811 with T2DM) from the region of Kuopio, eastern Finland. To further explore the putative mechanisms linking TNMD to T2DM and metabolic syndrome, we studied the associations of TNMD sequence variation with lipid abnormalities characteristic to metabolic syndrome. The association with T2DM risk was not replicated, but significant associations were found with serum low-density lipoprotein and total cholesterol in a body mass index-dependent manner. These associations were also observed in the men of DPS, whereas in women these associations were not significant. These results from two independent study populations suggest that the genetic variation in TNMD could modulate cholesterol metabolism in obese men.

Downregulation of genes involved in NFkappaB activation in peripheral blood mononuclear cells after weight loss is associated with the improvement of insulin sensitivity in individuals with the metabolic syndrome: the GENOBIN study.

AIMS/HYPOTHESIS: The transcription factor nuclear factor-kappa-B (NFkappaB) is implicated in inflammatory responses, obesity and the metabolic syndrome, while immune cells appear to play a central role in mediating insulin resistance and can be used as a model to study inflammation and its relationship with insulin resistance. In peripheral blood mononuclear cells of overweight participants with the metabolic syndrome, we evaluated (1) the effect of diet-induced weight loss on the expression of genes involved in NFkappaB activation and (2) their association with insulin sensitivity. The genes studied were: TNF receptors TNFRSF1A and TNFRSF1B, and IL1R1, TLR4, TLR2, ICAM1, CCL5 and IKBKB. METHODS: We analysed data from 34 overweight participants with abnormal glucose metabolism and the metabolic syndrome, who were randomised to a weight-reduction (n = 24) or control group (n = 10) for 33 weeks. The mRNA expression was measured using real-time PCR. Measures of insulin and glucose homeostasis were assessed by IVGTT and OGTT. RESULTS: In general, the genes studied were downregulated after weight loss intervention. The changes in TLR4, TLR2, CCL5 and TNFRSF1A mRNA expression were associated with an increase in insulin sensitivity index independently of the change in waist circumference (p < 0.05). The change in IKBKB expression correlated with most of the changes in gene expression in the weight-reduction group. CONCLUSIONS/INTERPRETATION: These results suggest that proteins encoded by CCL5, TLR2 and TLR4, and TNFRSF1A might contribute to insulin-resistant states that characterise obesity and the metabolic syndrome. TRIAL REGISTRATION: ClinicalTrials.gov NCT 00621205.

Chernobyl exposure as stressor during pregnancy and hormone levels in adolescent offspring.

BACKGROUND: Animal research suggests a programming effect of prenatal stress in the fetal period, resulting in disruptions in behavioural and neuromotor development. Physiological changes that mediate these effects include alterations in the hypothalamic-pituitary-adrenal axis and in testosterone levels. This human study focuses on changes related to these physiological systems after prenatal stress exposure. METHODS: We examined the potential effect of prenatal stress associated with the Chernobyl disaster in an ongoing genetic epidemiological study in Finland. One birth cohort of twins (n = 121 twin pairs) was exposed in utero to maternal stress, and their saliva cortisol and testosterone levels at age 14 were compared with twins (n = 157 twin pairs) born one year later. RESULTS: Cortisol levels in both sexes and testosterone levels among females were significantly elevated after prenatal exposure to maternal stress from the second trimester onwards, compared to reference groups of non-exposed adolescents. Exposure explains 3% of variance (p<0.05) in cortisol levels and 18% of variance in testosterone levels (p<0.001). No significant differences were found for exposure from either first or third trimester onwards. CONCLUSION: Our results suggest that prenatal exposure to maternal stress in the second trimester of pregnancy may have resulted in prenatal programming of physiological systems relating to cortisol and testosterone levels.

Serum concentrations and expressions of serum amyloid A and leptin in adipose tissue are interrelated: the Genobin Study.

OBJECTIVE: Serum amyloid A (SAA) is a novel link between increased adipose tissue mass and low-grade inflammation in obesity. Little is known about the factors regulating its serum concentration and mRNA levels. We investigated the association between SAA and leptin in obese and normal weight subjects and analyzed the effect of weight reduction on serum SAA concentration and gene expression in adipose tissue of the obese subjects. METHODS: Seventy-five obese subjects (60+/-7 years, body mass index (BMI) 32.9+/-2.8 kg/m(2), mean+/-s.d.) with impaired fasting plasma glucose or impaired glucose tolerance and other features of metabolic syndrome, and 11 normal weight control subjects (48+/-9 years, BMI 23.7+/-1.9 kg/m(2)) were studied at the baseline. Twenty-eight obese subjects underwent a 12-week intensive weight reduction program followed by 5 months of weight maintenance. Blood samples and abdominal s.c. adipose tissue biopsies were taken at the baseline and after the follow-up. Gene expression was studied using real-time quantitative PCR. RESULTS: The gene expressions in women and serum concentrations of leptin and SAA were interrelated independently of body fat mass in the obese subjects (r=0.54, P=0.001; r=0.24, P=0.039 respectively). In multiple linear regression analyses, leptin mRNA explained 38% of the variance in SAA mRNA (P=0.002) in the obese women. Weight loss of at least 5% increased SAA mRNA expression by 48 and 36% in men and women, but serum SAA concentrations did not change. CONCLUSIONS: The association between SAA and leptin suggests an interaction between these two adipokines, which may have implications in inflammatory processes related to obesity and the metabolic syndrome.

Weight reduction modulates expression of genes involved in extracellular matrix and cell death: the GENOBIN study.

OBJECTIVE: Lifestyle and genetic factors interact in the development of obesity and the metabolic syndrome. The molecular mechanisms underlying the beneficial dietary modifications are, however, unclear. We aimed to examine the effect of the long-term moderate weight reduction on gene expression in adipose tissue (AT) and to identify genes and gene clusters responsive to treatment and thereby likely contributing to the development of the metabolic syndrome. DESIGN: Randomized controlled and individualized weight reduction intervention. SUBJECTS: Forty-six subjects with impaired fasting glycemia or impaired glucose tolerance and features of metabolic syndrome, aged 60+/-7 years were randomized either to a weight reduction (WR) (n=28) or a control (n=18) group lasting for 33 weeks. MEASUREMENTS: Oral and intravenous glucose tolerance tests and subcutaneous AT biopsies were performed before and after the intervention. Gene expression of AT was studied using microarray technology in subgroups of WR (with weight reduction > or =5%, n=9) and control group (n=10). The results were confirmed using quantitative PCR. RESULTS: In the WR group, glucose metabolism improved. Moreover, an inverse correlation between the change in S (I) and the change in body weight was found (r=-0.44, P=0.026). Downregulation of gene expression (P<0.01) involving gene ontology groups of extracellular matrix and cell death was seen. Such changes did not occur in the control group. The tenomodulin-gene was one of the most downregulated genes (-39+/-16%, P<0.0001). Moreover, its expression correlated with insulin sensitivity (r=-0.34, P=0.005) before the intervention and with body adiposity both before (r=0.42, P=0.007) and after (r=0.30, P=0.056) the intervention. CONCLUSION: Genes regulating the extracellular matrix and cell death showed a strong downregulation after long-term weight reduction. This likely reflects a new stable state at the molecular level in AT. Further studies are warranted to elucidate the mechanisms of these genetic factors.

Chernobyl exposure as stressor during pregnancy and behaviour in adolescent offspring.

OBJECTIVE: Research in animals has shown that exposure to stressors during pregnancy is associated with offspring behavioural disorders. We aimed to study the effect of in utero exposure to the Chernobyl disaster in 1986, and maternal anxiety presumably associated with that exposure, on behaviour disorder observed at age 14. METHOD: Exposed (n = 232) and non-exposed Finnish twins (n = 572) were compared. A semi-structured interview was used to assess lifetime symptoms of depression, generalized anxiety disorder, attention deficit hyperactivity disorder, conduct disorder and oppositional defiant disorder symptoms. RESULTS: Adolescents who were exposed from the second trimester in pregnancy onwards, had a 2.32-fold risk (95% CI: 1.13-4.72) of having lifetime depression symptoms, an increased risk of fulfilling DSM-III-R criteria of a major depressive disorder (OR = 2.48, 95% CI: 1.06-5.7), and a 2.01-fold risk (95% CI: 1.14-3.52) of having attention deficit hyperactivity disorder symptoms. CONCLUSION: Perturbations in fetal brain development during the second trimester may be associated with the increased prevalence of depressive and attention deficit hyperactivity disorder symptoms.

Association of the Leu72Met polymorphism of the ghrelin gene with the risk of Type 2 diabetes in subjects with impaired glucose tolerance in the Finnish Diabetes Prevention Study.

AIMS: Ghrelin is a gut-brain regulatory peptide stimulating appetite and controlling energy balance. In previous studies, the Leu72Met polymorphism of the ghrelin gene has been associated with obesity and impaired insulin secretion. We investigated whether the Leu72Met polymorphism is associated with the incidence of Type 2 diabetes in subjects with impaired glucose tolerance (IGT) participating in the Finnish Diabetes Prevention Study (DPS). METHODS: DPS was a longitudinal intervention study carried out in five participating centres in Finland. A total of 522 subjects with IGT were randomized into either an intervention or a control group and DNA was available from 507 subjects. The Leu72Met polymorphism was screened by the restriction fragment length polymorphism method. RESULTS: There were no differences in clinical and anthropometric characteristics among the genotypes at baseline. IGT subjects with the Met72 allele were at higher risk of developing Type 2 diabetes than subjects with the Leu72Leu genotype (P = 0.046). Our data also demonstrated that IGT subjects with the common Leu72Leu genotype developed Type 2 diabetes less frequently under intervention circumstances than subjects with the Met72 allele (OR = 0.28, 95% CI 0.10-0.79; P = 0.016). CONCLUSIONS: Subjects with the Leu72Leu genotype had a lower risk for the development of Type 2 diabetes. This was observed particularly in the study subjects who underwent an intensive diet and exercise intervention. Defective first-phase insulin secretion related to the Met72 allele might be one factor contributing to the conversion to Type 2 diabetes.

Association of sequence variations in the gene encoding adiponectin receptor 1 (ADIPOR1) with body size and insulin levels. The Finnish Diabetes Prevention Study.

AIMS/HYPOTHESIS: Adiponectin is a circulating peptide derived from adipose tissue. It mediates its insulin-sensitising and anti-atherogenic effects on target tissues through two known receptors, adiponectin receptors 1 and 2 (ADIPOR1; ADIPOR2), which are encoded by the genes ADIPOR1 and ADIPOR2. Our aim was to study the association of ADIPOR1 gene variations with body size and risk of type 2 diabetes in subjects with impaired glucose tolerance, who participated in the Finnish Diabetes Prevention Study (DPS). SUBJECTS AND METHODS: We selected seven single nucleotide polymorphisms (SNPs) of the ADIPOR1 gene to perform association studies with anthropometrics and metabolic parameters at baseline, and with the risk of type 2 diabetes during the 3-year follow-up in the DPS study population. Both single SNP analysis and haplotype effects were studied. RESULTS: Three out of seven markers studied (rs10920534, rs22757538 and rs1342387) were significantly associated with various body size measurements including weight, height, waist and hip circumference, sagittal diameter and body mass index. Furthermore, three markers (rs10920534, rs12045862 and rs7539542), of which two were different from those associating with body size, were linked to fasting and 2-h insulin levels, particularly in men at baseline. The haplotype analysis with five markers revealed seven major haplotypes in the DPS study population. The haplotype effects on body size measures were in line with those of single SNP analysis. However, none of the markers were associated with the risk of type 2 diabetes. CONCLUSIONS/INTERPRETATION: Our findings suggest that ADIPOR1 has a putative role in the development of body size, and that traits for central adiposity and insulin resistance may be dissociated from each other.

Genetic variation in leptin receptor gene is associated with type 2 diabetes and body weight: The Finnish Diabetes Prevention Study.

OBJECTIVE: Genetic variation in leptin receptor (LEPR) gene has been reported to associate with insulin and glucose metabolism and adiposity in different study settings and various populations. We wanted to evaluate the association between LEPR polymorphisms, diabetes risk and body weight in Finnish subjects with impaired glucose tolerance (IGT). METHODS: We investigated the associations of the three LEPR polymorphisms (Lys109Arg, Gln223Arg, 3'UTR Del/Ins) with the conversion to type 2 diabetes and the changes in body weight in 507 individuals with IGT participating in the Finnish Diabetes Prevention Study. Participants were randomized to either an intensive diet and exercise intervention group or a control group. RESULTS: After 3 years, the odds ratio for the development of type 2 diabetes in individuals in the control group with the Lys109Lys genotype was 2.38-fold higher than in individuals with other genotype combinations (P=0.016). Irrespective of group individuals with the Gln223Gln genotype had higher conversion to type 2 diabetes (OR 2.01 (95% CI 1.03-3.93)) than the Arg223 allele carriers (P=0.042). The risk was more pronounced in the control group than in the intervention group. Individuals having the 3'UTR Del/Del genotype had a slightly higher body weight throughout the study than those with the insertion allele (P=0.020), although no difference in weight change was observed. CONCLUSION: Two polymorphisms (Lys109Arg, Gln223Arg) in the extracellular domain of the leptin receptor predicted the conversion to type 2 diabetes in high-risk individuals with IGT. The Del/Ins polymorphism in the 3'UTR of LEPR was associated with body weight.

Novel member of the mouse desmoglein gene family: Dsg1-beta.

Desmosomes are major intercellular adhesion junctions that provide stable cell-cell contacts and mechanical strength to epithelial tissues by anchoring cytokeratin intermediate filaments of adjacent cells. Desmogleins (Dsg) are transmembrane core components of the desmosomes, and belong to the cadherin supergene family of calcium-dependent adhesion molecules. Currently, there are three known isoforms of Dsgs (Dsg1, Dsg2, and Dsg3), encoded by distinct genes that are differentially expressed to determine their tissue specificity and differentiation state of epithelial cells. In this study, we cloned a novel mouse desmoglein gene sharing high homology to both mouse and human Dsg1. We propose to designate the previously published mouse Dsg1 gene as Dsg1-alpha and the new gene as Dsg1-beta. Analysis of intron/exon organization of the Dsg1-alpha and Dsg1-beta genes revealed significant conservation. The full-length mouse Dsg1-beta cDNA contains an open reading frame of 3180 bp encoding a precursor protein of 1060 amino acids. Dsg1-beta protein shares 94% and 76% identity with mouse Dsg1-alpha and human DSG1, respectively. RT-PCR using a multitissue cDNA panel demonstrated that while Dsg1-alpha mRNA was expressed in 15- to 17-day-old embryos and adult spleen and testis, Dsg1-beta mRNA was detected in 17-day-old embryos only. To assess subcellular localization, a FLAG-tagged expression construct of Dsg1-beta was transiently expressed in epithelial HaCaT cells. Dsg1-beta-FLAG was found at the cell-cell border and was recognized by the anti-Dsg1/Dsg2 antibody DG3.10. In summary, we have cloned and characterized a novel member of the mouse desmoglein gene family, Dsg1-beta.

Identification of ABCC6 pseudogenes on human chromosome 16p: implications for mutation detection in pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE), a heritable disorder affecting the skin, eyes, and the cardiovascular system, has recently been linked to mutations in the ABCC6 gene on chromosome 16p13.1. The original mutation detection strategy employed by us consisted of the amplification of each exon of the ABCC6 gene with primer pairs placed on the flanking introns, followed by heteroduplex scanning and direct nucleotide sequencing. However, this approach suggested the presence of multiple copies of the 5'-region of the gene when total genomic DNA was used as a template. In this study, we have identified two pseudogenes containing sequences highly homologous to the 5'-end of ABCC6. First, by the use of allele-specific polymerase chain reaction (PCR), two bacterial artificial chromosome (BAC) clones containing a putative pseudogene of ABCC6, designated as ABCC6-psi 1, were isolated from the human BAC library. Sequence analysis of ABCC6-psi 1 revealed it to be a truncated copy of ABCC6, which contains the upstream region and exon 1 through intron 9 of the gene. Secondly, a homology search of a high-throughput sequence database revealed the presence of another truncated copy of ABCC6, which was designated as ABCC6-psi 2, and which was shown to harbor upstream sequences and a segment spanning exon 1 through intron 4 of ABCC6. In addition to several nucleotide differences in the flanking introns and the upstream region, both pseudogenes contain several nucleotide changes in the exonic sequences, including stop codon mutations, which complicate mutation analysis in patients with PXE. Nucleotide differences in flanking introns between these two pseudogenes and ABCC6 allowed us to design allele-specific primers that eliminated the amplification of both pseudogene sequences by PCR and provided reliable amplification of ABCC6-specific sequences only. The use of allele-specific PCR has revealed, thus far, two novel 5'-end PXE mutations, 179del9 and T364R in exons 2 and 9, respectively, and several polymorphisms within the upstream region and exons 1-9 of ABCC6. These strategies facilitate comprehensive analysis of ABCC6 for mutations in PXE.

Drinking or abstaining at age 14? A genetic epidemiological study.

BACKGROUND: Regular drinking by age 14 years is a significant risk factor for alcoholism, and genetically informative data suggest that whether a young adolescent abstains or drinks is largely attributable to familial (or other shared) environmental factors. METHODS: Three consecutive birth cohorts of Finnish twins, enrolled into a longitudinal study at age 11 to 12 years, completed a follow-up questionnaire within 3 months of their 14th birthdays. The sample included 1380 twin sisters and 1330 twin brothers at age 14, and at that age, 35.4% reported using alcohol. Genetic analyses (model-fitting of twin pair data) and epidemiological analyses (logistical regressions of data from individual twins) were conducted to examine predictive factors of drinking versus abstinence at age 14. RESULTS: Polychoric correlations were substantial across all same-sex twin pairs but were lower for brother-sister twins, suggesting significant influences of common environments, with some sex-specific effects. Common environmental effects were equivalent in male and female adolescents and accounted for 76% of the total variation in abstinence/drinking. Logistical regression analyses among 2206 individual twins with complete data on risk-relevant measures at both baseline and follow-up identified significant predictors of drinking or abstaining at age 14, including female sex, twin sibling of the opposite sex, accelerated pubertal development, and the twins' assessments, made at age 12, of reduced parental monitoring and a less supportive home atmosphere; drinking at age 14 was also predicted by behaviors rated by the twins' classroom teachers 2 years earlier, increasing with rated behavioral problems but decreasing with rated emotional problems. CONCLUSIONS: Our results show that environmental factors shared by twin siblings account for most of the variance in abstaining or drinking at age 14. We identify predictors of drinking in the adolescent twins' home environments and in their dispositional behaviors, sibling interactions, and pubertal timing.

Molecular genetics of heritable blistering disorders.

Over the past decade, there has been tremendous progress in understanding the genetic basis of different forms of genodermatoses. Specifically, with the advent of technologies in molecular biology in general, an increasingly large number of gene defects have been identified in different genodermatoses, and mutations are now known to occur in more than 100 distinct genes in such a manner that the genetic lesions explain the spectrum of phenotypic manifestations encountered in these diseases.