Unrelated Control Subjects Research Articles

Dopamine D2 receptor polymorphisms and susceptibility to alcohol dependence in Indian males: a preliminary study

BackgroundDopamine is an important neurotransmitter involved in reward mechanism in the brain and thereby influences development and relapse of alcohol dependence. The dopamine D2 receptor (DRD2) gene on chromosome 11 (q22-q23) has been found to be associated with increased alcohol consumption through mechanisms involving incentive salience attributions and craving in alcoholic patients. Therefore, we investigated the association of three single nucleotide polymorphisms (SNP) in DRD2 gene with alcohol dependence in the north Indian subjects.MethodsIn a retrospective analysis, genetic association of three polymorphisms from DRD2 gene with alcohol dependence was investigated using a case-control approach. Alcohol dependence was determined by DSM-IV criteria and a total of 90 alcoholics and 60 healthy unrelated age-matched control subjects were recruited. Odds ratio and confidence interval was calculated to determine risk conferred by a predisposing allele/genotype/haplotype. Logistic regression analysis was carried out to correlate various clinical parameters with genotypes, and to study pair-wise interactions between SNPs.ResultsThe study showed a significant association of -141C Ins allele and a trend of association of TaqI A1 allele of DRD2 with alcohol dependence. Haplotype with the predisposing -141C Ins and TaqI A1 alleles (-141C Ins-A-A1) seems to confer ≈ 2.5 times more risk to develop alcohol dependence.ConclusionsThe study provides preliminary insight into genetic risk to alcohol dependence in Indian males. Two polymorphisms namely, -141C Ins/Del and TaqI A in DRD2 gene may have clinical implications among Indian alcoholic subjects.

Mutations in the Lysosomal Enzyme–Targeting Pathway and Persistent Stuttering

Stuttering is a disorder of unknown cause characterized by repetitions, prolongations, and interruptions in the flow of speech. Genetic factors have been implicated in this disorder, and previous studies of stuttering have identified linkage to markers on chromosome 12. We analyzed the chromosome 12q23.3 genomic region in consanguineous Pakistani families, some members of which had nonsyndromic stuttering and in unrelated case and control subjects from Pakistan and North America. We identified a missense mutation in the N-acetylglucosamine-1-phosphate transferase gene (GNPTAB), which encodes the alpha and beta catalytic subunits of GlcNAc-phosphotransferase (GNPT [EC 2.7.8.15]), that was associated with stuttering in a large, consanguineous Pakistani family. This mutation occurred in the affected members of approximately 10% of Pakistani families studied, but it occurred only once in 192 chromosomes from unaffected, unrelated Pakistani control subjects and was not observed in 552 chromosomes from unaffected, unrelated North American control subjects. This and three other mutations in GNPTAB occurred in unrelated subjects with stuttering but not in control subjects. We also identified three mutations in the GNPTG gene, which encodes the gamma subunit of GNPT, in affected subjects of Asian and European descent but not in control subjects. Furthermore, we identified three mutations in the NAGPA gene, which encodes the so-called uncovering enzyme, in other affected subjects but not in control subjects. These genes encode enzymes that generate the mannose-6-phosphate signal, which directs a diverse group of hydrolases to the lysosome. Deficits in this system are associated with the mucolipidoses, rare lysosomal storage disorders that are most commonly associated with bone, connective tissue, and neurologic symptoms. Susceptibility to nonsyndromic stuttering is associated with variations in genes governing lysosomal metabolism.

Association of angiotensin converting enzyme and angiotensin type 2 receptor gene polymorphisms with renal damage in posterior urethral valves

To examine the association with renal damage in patients with posterior urethral valves (PUV) of two renin-angiotensin system gene polymorphisms: angiotensin converting enzyme insertion/deletion (ACE I/D) and angiotensin type 2 receptor (AT2R A1332G), PATIENTS AND METHODS: In 120 patients with PUV, after stabilization, transurethral fulguration or a Blocksom vesicostomy was performed. Records were reviewed for age at diagnosis, biochemical renal function at diagnosis, results of urine cultures, voiding cystourethrograms, radiologic, sonographic and nuclear medicine scan findings, and follow-up data. ACE I/D genotypes were determined by the polymerase chain reaction using allele specific primers. The frequency of the ACE DD genotype was significantly higher in patients with chronic kidney disease (P=0.02) and renal scarring (P=0.05). These genotypes were also associated with a statistically higher incidence of vesicoureteral reflux, diurnal incontinence, proteinuria and hypertension. A significantly higher frequency of the AT2R GG genotype was found in PUV patients as compared to healthy unrelated control subjects (P=0.001), and in PUV patients with scarring (P=0.02). The ACE DD and AT2R GG genotypes are associated with chronic kidney disease and scarring in PUV patients. The GG genotype incidence is higher among PUV patients compared to the control population, and further studies in this area may help understanding of the genetic basis of PUV.

Association between novel TARDBP mutations and Chinese patients with amyotrophic lateral sclerosis

BackgroundTARDBP mutations have been reported in patients with amyotrophic lateral sclerosis (ALS) in different populations except Chinese. The present aim is to investigate the association between TARDBP mutations and Chinese patients with ALS.Methods71 SALS patients and 5 FALS families with non-SOD1 mutations were screened for TARDBP mutations via direct sequencing.ResultsA novel heterozygous variation, Ser292Asn (875G>A), was identified in the proband and 4 asymptomatic relatives including the children of the dead patient from a FALS family. Thus the dead patient, the proband's brother, was speculated to carry Ser292Asn though his sample was unavailable to the detection. This variation was not found in 200 unrelated control subjects. A homology search of the TDP-43 protein in different species demonstrated that it was highly conserved. Also, it was predicted to be deleterious to protein function with SIFT-calculated probabilities of 0.00. Therefore, Ser292Asn is predicted to be a pathogenic mutation. In addition, we have found two silent mutations (Gly40Gly and Ala366Ala) and one novel polymorphism (239-18t>c).ConclusionsThe present data have extended the spectrum of TARDBP mutations and polymorphisms, and supported the pathological role of TDP-43 in Chinese ALS patients.

PARKIN-coding polymorphisms are not associated with Parkinson's disease in a population from northeastern Mexico

Early- and late-onset Parkinson's disease (EOPD and LOPD) have been associated with mutations in the PARKIN gene. Several studies have reported association of Parkinson's disease (PD) with different polymorphisms in different ethnic populations. To study the role of PARKIN polymorphisms as risk factors for PD in a genetically homogeneous northeastern Mexican population, four previously described coding polymorphisms (Ser167Asn, Val380Leu, Arg366Trp, and Asp394Asn) were analyzed by using the PCR-RFLP technique. This case–control study comprised 117 unrelated patients (mean age 59 ± 12 years, range 25–83 years) and 122 healthy unrelated control subjects (mean age 50 ± 15 years, range 25–85 years). The homozygous Trp366 and Asn394 genotypes were not present in our study. The Ser167Asn and Val380Leu polymorphisms were not associated with this disease. For the control group, Ser167Asn and Val380Leu were in Hardy–Weinberg disequilibrium. Given that the main causes of Hardy–Weinberg disequilibrium in controls are selection bias or genotyping error, a competing risk of death associated with the mutant gene could be an explanation of this disequilibrium and lack of association.

Analysis of 14 genetic polymorphisms for risk factors in Malaysian essential hypertension with or without type 2 diabetes mellitus subjects

Objectives The objective of this study was to determine the association of insertion/deletion (I/D), G2350A and T3892C polymorphisms of angiotensin converting enzyme (ACE) gene, A20C and A6G polymorphism of angiotensinogen (AGT) gene, BglI and MboI polymorphisms of renin gene, I/D of alpha 2B adrenoceptor gene, Gly460Trp of aldosterone synthase gene, Lys173Arg of adducin gene, A6244G polymorphism of the insulin receptor gene, S477X polymorphism of the lipoprotein lipase gene, C511T polymorphism of the interleukin gene and C825T polymorphism of the G protein beta 3 subunit (GNβ3) gene in essential hypertension (EHT) with or without type 2 diabetes mellitus (T2DM) of Malaysian subjects. Methods This cross-sectional study includes 70 EHT without T2DM, 65 EHT with T2DM and 75 unrelated healthy control subjects. Genomic DNA was extracted from the peripheral blood. The polymerase chain reaction (PCR)-restriction fragment length polymorphism, mutagenically PCR and the hot-start PCR methods were carried out to detect the genotypes of the various genetic polymorphisms. All the PCR products and the restricted fragments were resolved electrophoretically on agarose and polyacrylamide gels. Statistical analyses was done using SPPS version 14.0. Results Among the 14 genetic polymorphisms, only I/D and G2350A polymorphism of ACE gene, I/D polymorphism of alpha adrenoceptor gene and A6G variant of AGT gene differed significantly (p 0.05) when compared to control subjects. Conclusions The alleles of I/D and G2350A polymorphisms of ACE, A6G of AGT and I/D of alpha 2B adrenoceptor genes can be considered as possible genetic markers or predisposing risk factors for EHT with or without T2DM in Malaysian subjects.

Interactions among genetic variants from SREBP2 activating-related pathway on risk of coronary heart disease in Chinese Han population

Sterol regulatory element binding proteins (SREBPs), as a family of membrane-bound transcription factors, control the metabolism of cholesterol and fatty acids. We conducted a case-control study to investigate whether the common variants of genes from the SREBP2 activating-related pathway, involving SREBP2, SCAP, INSIG1 and INSIG2 genes, were associated with coronary heart disease (CHD) of Chinese Han population individually or interactively. Three, four and two single nucleotide polymorphisms (SNPs) from the INSIG1, INSIG2 and SCAP genes were chosen as haplotype-tagging SNPs (htSNPs), respectively, and one nonsynonymous coding SNP was selected from SREBP2. All of the SNPs were genotyped in 853 CHD cases and 948 unrelated control subjects. The interactions among SNPs of the four genes were evaluated with multifactor-dimensionality reduction (MDR) and logistic regression models (LRM). The results from MDR indicated that there existed the SNP-SNP interactive effect of INSIG1 gene on CHD (best prediction accuracy=56.09%, p=0.002 on 1000 permutations). The results from LRM also identified the 2-locus interaction model (adjusted p≤0.001 for interaction) as well as the 3-locus gene–gene interaction (adjusted p=0.026 for interaction). Single polymorphism analysis showed that the rs4822063 of SREBP2 was associated with LDL-C in the controls. The genotype CC carriers had higher LDL-C than the major allele G carriers (3.44±0.90mmol/L versus 3.17±0.84mmol/L, adjusted p=0.038). Our results suggested that the INSIG1 gene was associated with CHD; there might be potential interactive effect on CHD among genes from SREBP2 activating-related pathway; and the SREBP2 gene might be associated with plasma lipid level.

Combining Case-Control and Case-Trio Data From the Same Population in Genetic Association Analyses: Overview of Approaches and Illustration With a Candidate Gene Study

In genetic association studies, investigators compare allele or genotype frequencies in unrelated case and control subjects or examine preferential allele transmissions from parents to affected offspring. In many genetic case-control studies, the collection of DNA material extends to relatives such as parents of cases. Thus, case-control and case-parent trio association analyses are possible. Whereas the goal of collecting genetic information from family members in a study initially designed as a case-control study is to enrich the genetic analysis, increase power, or address concern about population structure bias, methods of combining genetic data from unrelated case and control subjects with genetic trio data from the same study population are not well known. A number of hybrid approaches have been developed that utilize such data together. In this paper, the authors describe key features of genetic case-control and case-parent trio studies and review commonly used methods of genetic analysis for case-parent trio designs. In addition, they provide a pragmatic review of statistical methods and available software for existing hybrid approaches that combine various components of case-control and genetic trio data. The application of all methods is illustrated using a candidate gene study of childhood leukemia that included case-control subjects and their parents.

Accurate, Large-Scale Genotyping of 5HTTLPR and Flanking Single Nucleotide Polymorphisms in an Association Study of Depression, Anxiety, and Personality Measures

The length polymorphism repeat in the promoter region of the serotonin transporter gene (5HTTLPR) is one of the most studied polymorphisms for association with a range of psychiatric and personality phenotypes. However, the original 5HTTLPR assay is prone to bias toward short allele calling. We designed new assays for the 5HTTLPR suitable for large-scale genotyping projects and we genotyped 13 single nucleotide polymorphisms (SNPs) in a 38-kilobase region around the 5HTTLPR, including SNP rs25531, a polymorphism of the 5HTTLPR long allele. Association analysis was conducted for major depression and/or anxiety disorder in unrelated cases (n = 1161) and control subjects (n = 1051) identified through psychiatric interviews administered to a large population sample of Australian twin families. Participants had been scored for personality traits several years earlier (n > or = 2643 unrelated individuals). We identified a two-SNP haplotype proxy for 5HTTLPR; the CA haplotype of SNPs rs4251417 and rs2020934 is coupled with the short allele of 5HTTLPR (r(2) = .72). We found evidence for association (p = .0062, after accounting for multiple testing) for SLC6A4 SNPs rs6354 and rs2020936 (positioned in a different linkage disequilibrium [LD] block about 15.5 kb from 5HTTLPR) with anxiety and/or depression and neuroticism, with the strongest association for recurrent depression with onset in young adulthood (odds ratio = 1.55, 95% confidence interval = 1.16-2.06). The associated SNPs are in the same LD block as the variable number of tandem repeats serotonin transporter intron 2 marker, for which association has previously been reported.

Segawa syndrome due to mutation Q89X in the GCH1 gene: a possible founder effect in Córdoba (southern Spain)

Autosomal dominant guanosine triphosphate cyclohydrolase I deficiency is an inborn error of neurotransmitter metabolism, with a prevalence of 0.5 per million, caused by mutations/deletions in the GCH1 gene. The finding of the mutation Q89X in the GCH1 gene in 23 patients from two pedigrees in an area inhabited by a population of 800,000 prompted us to consider that our cohort may have descended from a single founder. Twelve Q89X mutation-positive cases belonging to two families and 100 unrelated control subjects from the same geographical region were studied. Six microsatellite markers located near GCH1 were analyzed to validate a possible mutation-related founder haplotype. Haplotype analysis revealed two different haplotypes for six microsatellite markers that segregated with the Q89X mutation. A common haplotype in 10 out of 12 mutation carriers studied was identified. Two subjects carried a second haplotype, most probably because of a recombination event. However, at least 186 different haplotypes were established in the control subjects. In contrast with the frequencies of 83.3% and 16.7%, respectively, found for both mutation-segregating haplotypes, the frequency of none of the control haplotypes exceeded 1.5%. Dystonia was the most frequent symptom in our series, and parkinsonism was present in five patients. The large number of Q89X mutation carriers in our community is because of a founder effect. The same mutation in GCH1 causes a wide phenotypic spectrum of clinical variability occurring in this population of affected patients.

THE D216H VARIANT IN THE DYT1 GENE: A SUSCEPTIBILITY FACTOR FOR DYSTONIA IN FAMILIAL CASES?

Primary focal dystonia is a clinically and genetically heterogeneous disorder. In contrast, early-onset generalized torsion dystonia is often caused by a heterozygous deletion of three nucleotides (GAG) in the DYT1 gene leading to the loss of a glutamic acid residue (deltaE) of the gene product TorsinA.1 Interestingly, the only nonsynonymous coding sequence variation in DYT1 , rs1801968 (D216H), was demonstrated to reduce penetrance of the GAG deletion when present in trans to this mutation.2 While one study suggested a protective effect of H216 in a small number of tested Indian patients with primary dystonia, other reports failed to show any association.3–5 The aim of the present study was to evaluate the role of D216H in German patients with familial primary dystonia and, in case of association, to establish the frequency of this variant in patients with dystonia regardless of their family history. ### Subjects. Study subjects were recruited from four movement disorders centers in Northern Germany. After obtaining informed consent and approval of the study by the local ethical standards committee, all participants underwent a standardized neurologic examination by a movement disorders specialist, and blood samples were drawn. We included 111 unrelated familial cases with primary focal or segmental dystonia, along with 241 unrelated control subjects. Family history was regarded as positive when at least one …

A novel homozygous missense mutation of the leptin gene (N103K) in an obese Egyptian patient

Congenital leptin deficiency is a rare recessive genetic disorder resulting in severe hyperphagia and early onset obesity. It is caused by mutations in the LEP gene encoding leptin. To date, only two mutations have been identified in the LEP gene, Δ133G and R105W. We present the third reported mutation identified in an Egyptian patient with very low serum leptin levels and severe early onset obesity (BMI = 51). Direct sequencing of the coding region of the LEP gene revealed a novel homozygous missense mutation, N103K. The N103K mutation was not found in 100 alleles from 50 unrelated Egyptian normal-weight control subjects using polymerase chain reaction and restriction fragment length polymorphism analysis. In conclusion, this study presents the third reported mutation of the LEP gene and will provide further insight into the physiologic role of leptin in human obesity.

Genetic Analysis of Indian Families with Autosomal Recessive Retinitis Pigmentosa by Homozygosity Screening

To identify the disease-causing genes in families with autosomal recessive RP (ARRP). Families were screened for homozygosity at candidate gene loci followed by screening of the selected gene for pathogenic mutations if homozygosity was present at a given locus. A total of 34 families were included, of which 24 were consanguineous. Twenty-three genes were selected for screening. The presence of homozygosity was assessed by genotyping flanking microsatellite markers at each locus in affected individuals. Mutations were detected by sequencing of coding regions of genes. Sequence changes were tested for presence in 100 or more unrelated normal control subjects and for cosegregation in family members. Homozygosity was detected at one or more loci in affected individuals of 10 of 34 families. Homozygous disease cosegregating sequence changes (two frame-shift, two missense, and one nonsense; four novel) were found in the TULP1, RLBP1, ABCA4, RPE65, and RP1 genes in 5 of 10 families. These changes were absent in 100 normal control subjects. In addition, several polymorphisms and novel variants were found. All the putative pathogenic changes were associated with severe forms of RP with onset in childhood. Associated macular degeneration was found in three families with mutations in TULP1, ABCA4, and RP1 genes. Novel mutations were found in different ARRP genes. Mutations were detected in approximately 15% (5/34) of ARRP families tested, suggesting involvement of other genes in the remaining families.

Anti‐“Mia” immunization is associated with HLA‐DRB1*0901

Anti-"Mi(a)" is one of the most important irregular red blood cell antibodies found in Taiwan. The aim of this study was to investigate whether specific HLA-DRB1 alleles are associated with anti-"Mi(a)" production. A case-control retrospective study was performed on 68 patients showing presence of anti-"Mi(a)" and 219 unrelated control subjects from the Mackay Memorial Hospital. HLA-DRB1 genotyping was carried out using sequence-based typing method. Fisher's exact test using 2 x 2 contingency tables was used to analyze significance of the association between DRB1 polymorphisms and presence of anti-"Mi(a)" in patients. HLA-DRB1*0901 allele frequency in the anti-"Mi(a)" group (30%) was significantly higher than in the control group (16%) with an odds ratio of 2.27 (95% confidence interval, 1.44-3.55; p = 0.0005; p(c) = 0.016). HLA-DRB1*0901 is significantly more prevalent in the anti-"Mi(a)" patients group than in the control group. It is suggested that cells from DR9 individuals might present processed "Mi(a)" antigen-allospecific peptides more effectively than cells from individuals carrying other DR phenotypes. Finally, it was predicted that two epitopes, derived from the MiIII glycophorin amino acid sequence, were likely to bind preferentially with the DR9 molecule. Further work will be necessary to determine if these epitopes are responsible for anti-"Mi(a)" alloimmunization.

Two novel POLG mutations causing hepatic mitochondrial DNA depletion with recurrent hypoketotic hypoglycaemia and fatal liver dysfunction

Inherited mtDNA depletion syndromes (MDS) are a group of severe mitochondrial disorders resulting from defects in nucleus-encoded factors and often associated with severe or fatal liver failure. In this article, we describe the case of an 18-month-old patient with recurrent hypoketotic hypoglycaemia and fatal hepatic dysfunction with liver mtDNA depletion. The assessment of mtDNA copy number was performed on leucocytes, liver and muscle biopsy by Quantitative Real Time PCR and total RNA from liver biopsy was used as a template to amplify the cDNA of the POLG1 gene. Sequence analysis identified two previously undescribed mutations (1868T>G and 2263A>G) located in the gene coding the catalytic subunit of mitochondrial DNA polymerase gamma (POLG), predicting an L623W and K755E amino acid change, respectively. Both mutations were located in the highly conserved linker region of the protein and were absent in more than 200 healthy unrelated control subjects. The identification of these two mutations allowed us to perform genetic counselling and prenatal diagnosis. Our data further expand the spectrum of POLG1 gene mutations and the unique phenotype reported (late onset isolated liver disease without lactic acidosis) increase the variability of clinical presentations associated with mutations in this gene.

Molecular analyses of GCH‐1, TH and parkin genes in Chinese dopa‐responsive dystonia families

The symptomatic treatment of dopa-responsive dystonia (DRD) emphasizes the importance of molecular analyses of the GCH-1, TH and parkin genes. However, these analyses have not been extensively studied in Chinese DRD patients. Ten DRD families from the Han ethnic group including 14 patients and 28 clinically unaffected relatives were screened for GCH-1, TH and parkin mutations by direct sequencing, semiquantitative polymerase chain reaction (PCR), polymerase chain reaction-restriction fragment length polymorphism analysis and allele-specific PCR. Variations were verified in 200 unrelated control subjects. We have identified six novel mutations and three known mutations. The novel mutations are Leu91Val, Pro95Leu, Val204Gly and 628delC in GCH-1 gene; Gly216Ser in TH gene; and Cys253Phe in parkin gene. After molecular analyses of seven families with identified GCH-1 mutations, nine asymptomatic cases were found among 23 relatives, which confirmed the low penetrance of DRD. Unlike previous publications, male patients with GCH-1 mutations have early onset ages, while some female patients have very late onset ages in this medium-size series. Our data show that it is difficult to establish an evident genotype-phenotype correlation for DRD. However, it is necessary to know the genetic defects of DRD patients in clinics, which will help elucidate the mode of inheritance, facilitate causal therapy with levodopa and evaluate the prognosis.

Association of the 17-hydroxysteroid dehydrogenase type 5 gene polymorphism (−71A/G HSD17B5 SNP) with hyperandrogenemia in polycystic ovary syndrome (PCOS)

To evaluate the association of an activating single-nucleotide polymorphism (SNP) at position -71 of the promoter of 17beta-hydroxysteroid dehydrogenase type 5 gene (-71A/G HSD17B5 SNP) and polycystic ovary syndrome (PCOS) in a well characterized cohort of caucasian PCOS women with biochemical hyperandrogenemia. The PCOS patients and unrelated healthy control subjects were genotyped for the -71A/G HSD17B5 SNP. The acquired genotypic data was tested for association with PCOS and other quantitative phenotypic traits of the syndrome in PCOS patients. Subjects were recruited from the Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, at the University Hospital of Patras, Greece. Genotyping and biochemical determinations took place at the Laboratory of Molecular Endrocinology, University of Patras Medical School, Rion, Greece. Participants comprised 150 caucasian Greek PCOS women with biochemical hyperandrogenism and chronic anovulation and polycystic ovarian morphology on ultrasound and 51 healthy control subjects. HSD17B5 genotype, serum testosterone, serum androstenedione. No association of the -71A/G HSD17B5 SNP with PCOS was detected. However, the -71G HSD17B5 variant was associated with increased serum testosterone levels and decreased androstenedione/testosterone ratio. The -71G HSD17B5 variant is not a major component of the molecular pathogenetic mechanisms of PCOS, although it might contribute to the severity of hyperandrogenemia in women with PCOS and biochemical hyperandrogenism.

Associations between polymorphisms in the mitochondrial uncoupling proteins ( UCPs) with T2DM

Background Mitochondrial uncoupling proteins (UCPs) are considered pivotal regulators of energy and glucose homeostasis. We examined the effect of 23 single nucleotide polymorphisms (SNPs) in the UCP genes on type 2 diabetes mellitus (T2DM) and related phenotypes to identify genetic factors that may be involved in susceptibility to T2DM. Methods We directly sequenced the coding region, portions of the 5′- and 3′-flanking sequences, and the intron–exon boundaries of the UCP genes from 24 individuals. We genotyped 23 SNPs in 761 unrelated patients with T2DM and 632 unrelated non-diabetic control subjects and investigated their potential involvement in T2DM. Results We identified association between T2DM and the following 3 SNPs in UCP2: UCP2 − 5331G> A ( P = 0.018, odds ratio (OR) = 1.38, 95% CI (confidence interval) = 1.06–1.79), UCP2 − 3998C> G ( P = 0.021, OR = 1.37, 95% CI = 1.05–1.78), and UCP2 + 320C> T ( P = 0.019, OR = 0.73, 95% CI = 0.57–0.95). There was strong linkage disequilibrium (LD) among these 3 SNPs ( r 2 = 0.94–0.97). UCP2 − 5331G> A is a regulatory SNP (rSNP), and its association with T2DM was significant among obese or abdominally obese subjects ( P = 0.017, OR = 1.78, 95% CI = 1.11–2.85; P = 0.004, OR = 1.82, 95% CI = 1.21–2.74; respectively). UCP3 − 2078C> T of UCP3 SNPs was associated with T2DM only among women ( P = 0.026, OR = 0.71, 95% CI = 0.52–0.96). Patients with combinations of the rSNPs UCP2 − 5331G> A and UCP3 − 2078C> T displayed an increased risk for T2DM. Specifically, those patients homozygous for both rSNPs among susceptible alleles had a higher risk for T2DM than patients heterozygous for one rSNP and homozygous for the other rSNP ( P = 0.033, OR = 1.38, 95% CI = 1.03–1.85). This association was more obvious in women ( P = 0.022, OR = 1.58, 95% CI = 1.07–2.34). Conclusions Our results suggest that the UCP2 − 5331G> A and UCP3 − 2078C> T polymorphisms are susceptibility markers for T2DM among Koreans.

A Risk Allele for Nicotine Dependence in CHRNA5 Is a Protective Allele for Cocaine Dependence

A nonsynonymous coding polymorphism, rs16969968, of the CHRNA5 gene that encodes the alpha-5 subunit of the nicotinic acetylcholine receptor (nAChR) has been found to be associated with nicotine dependence. The goal of this study was to examine the association of this variant with cocaine dependence. Genetic association analysis was performed in two independent samples of unrelated case and control subjects: 1) 504 European Americans participating in the Family Study on Cocaine Dependence (FSCD) and 2) 814 European Americans participating in the Collaborative Study on the Genetics of Alcoholism (COGA). In the FSCD, there was a significant association between the CHRNA5 variant and cocaine dependence (odds ratio = .67 per allele, p = .0045, assuming an additive genetic model), but in the reverse direction compared with that previously observed for nicotine dependence. In multivariate analyses that controlled for the effects of nicotine dependence, both the protective effect for cocaine dependence and the previously documented risk effect for nicotine dependence were statistically significant. The protective effect for cocaine dependence was replicated in the COGA sample. In COGA, effect sizes for habitual smoking, a proxy phenotype for nicotine dependence, were consistent with those observed in FSCD. The minor (A) allele of rs16969968, relative to the major G allele, appears to be both a risk factor for nicotine dependence and a protective factor for cocaine dependence. The biological plausibility of such a bidirectional association stems from the involvement of nAChRs with both excitatory and inhibitory modulation of dopamine-mediated reward pathways.

A patient with pseudohypoaldosteronism type II caused by a novel mutation in WNK4 gene

Pseudohypoaldosteronism Type II (PHAII) is a very rare disorder characterized by hyperkalemia, hypertension, and slight hyper-chloremic metabolic acidosis. The index patient showed typical features of PHAII, including elevated blood pressure (140-150/90-100 mmHg), hyperkalemia in the range of 5.30-5.60 mmol/l (normal range is 3.50-5.10 mmol/l), accompanied by hyperchloremia of 109.5-112.0 mmol/l (normal 95.0-108.0 mmol/l) and acidosis with bicarbonate levels of 19.5-20.1 mmol/l (normal 22.0-27.0), GFR was 98.95 ml/min (normal > 90). However, these features were absent in his parents. Sequencing analysis found the patient with a WNK4 gene mutation, 1682 C > T in Exon 7, which resulted a missense mutation at codon 561 (P561L). The variation in codon 561 was not found in his parents and 100 unrelated control subjects. The identified WNK4 mutation which has not been described previously is the probable cause of PHAII.