Mutation analysis of the retinoid X receptor beta,nuclear‐related receptor 1, and peroxisome proliferator‐activated receptor alpha genes in schizophrenia and alcohol dependence: Possible haplotype association of nuclear‐related receptor 1 gene to alcohol dependence

Because retinoid cascades are involved in the regulation and development of the central nervous system, including dopaminergic neurons, retinoic acid signaling defects may contribute to schizophrenia and substances dependence. Retinoid X receptors (RXRs) form heterodimer complexes with nuclear‐related receptor 1 (NURR1) or with peroxisome proliferator‐activated receptors (PPARs). We examined 48 Japanese patients with schizophrenia and 32 patients with alcohol dependence to detect mutations in the retinoid X receptor beta gene (RXRB) on chromosome 6p21.3, the NURR1 gene (NR4A2) on chromosome 2q22–q23, and the PPAR alpha gene (PPARA) on chromosome 22q12.2–13.1. A Val95Ala polymorphism of the RXRB gene, a Val227Ala polymorphism in the PPARA gene, and two synonymous single‐nucleotide and CA repeat polymorphisms in the 5′ region and 3′ untranslated region of the NR4A2 gene were identified. Extended case control samples did not suggest an association between the diseases and the RXRB or PPARA polymorphisms. However, they revealed a significant association between the NR4A2 gene haplotype and alcohol dependence, indicating that 2q22–q23 including the NR4A2 gene locus is a possible genomic region contributing to genetic susceptibility to alcohol dependence. © 2001 Wiley‐Liss, Inc.     

Systematic screening of the 14‐3‐3 eta (η) chain gene for polymorphic variants and case‐control analysis in schizophrenia

The neuronal protein 14‐3‐3 η is a candidate gene for schizophrenia because it maps chromosome 22q12, a region implicated in the disease by linkage analysis, and is involved in brain development. We systematically screened this gene for polymorphic variants by comparison of public EST sequence data (five cDNAs and 72 ESTs, 21,155 bp of sequence) in parallel with single‐stranded conformational polymorphism analysis, and we compared these methods by using a simple power calculation. Twelve potential polymorphisms were identified from EST sequence comparison, and two of these (a 5′‐VNTR and 753G/A) were confirmed by SSCP analysis and sequencing. Three additional infrequent polymorphisms (−408T/G; 177 C/G; and 989 A/G) were found by SSCP only. We next examined these variants for association with schizophrenia. One variant in untranslated region of exon 1 (−408 T/G) was found to occur more frequently in the schizophrenic subjects (8%) than the controls (3%; P = 0.01). After fivefold correction of the P value for multiple testing, marginal association was found. Haplotype analysis of pairs of polymorphisms provided no evidence for association of this gene with schizophrenia in the population studied. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:736–743, 2000. © 2000 Wiley‐Liss, Inc.     

14-3-3 protein η chain gene (YWHAH) polymorphism and its genetic association with schizophrenia

Recent genetic analyses have suggested a linkage between schizophrenia and the chromosomal region 22q12–q13. 14-3-3 protein, abundant in the brain, mediates interactions between diverse molecules of biological activities; its gene was recently mapped to chromosome 22q12.1–q13.1. We therefore investigated allele frequencies of a variable number of tandem repeat (VNTR) in the 5′-noncoding region of the 14-3-3 η chain gene in controls and schizophrenics. The frequencies of the two-repeat allele were significantly higher (P < 0.05) in the schizophrenics, and particularly in those with onset before age 22 (early-onset schizophrenics, P < 0.02), than in the controls. The odds ratio was significantly increased in the early-onset schizophrenics homozygous for the two-repeat allele (OR = 3.3, 95% CI = 1.1—9.7). The 14-3-3 η chain gene is a potential susceptibility gene for schizophrenia, and particularly for early-onset schizophrenia. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:164–167, 1999. © 1999 Wiley-Liss, Inc.     

Mutations of the Nogo-66 receptor (RTN4R) gene in schizophrenia

Schizophrenia (SCZD) or schizoaffective disorders are quite common features in patients with DiGeorge/velo-cardio-facial syndrome (DGS/VCFS) as a result of chromosome 22q11.2 aploinsufficiency. We evaluated the Nogo-66 receptor gene (RTN4R), which maps within the DGS/VCFS critical region, as a potential candidate for schizophrenia susceptibility. RTN4R encodes for a functional cell surface receptor, a glycosylphosphatidylinositol (GPI)-linked protein, with multiple leucine-rich repeats (LRR), which is implicated in axonal growth inhibition. One hundred and twenty unrelated Italian schizophrenic patients were screened for mutations in the RTN4R gene using denaturing high performance liquid chromatography (DHPLC). Three mutant alleles were detected, including two missense changes (c.355C>T; R119W and c.587G>A; R196H), and one synonymous codon variant (c.54G>A; L18L). The two schizophrenic patients with the missense changes were strongly resistant to the neuroleptic treatment at any dosage. Both missense changes were absent in 300 control subjects. Molecular modeling revealed that both changes lead to putative structural alterations of the native protein.     

14-3-3 protein eta chain gene (YWHAH) polymorphism and its genetic association with schizophrenia

Recent genetic analyses have suggested a linkage between schizophrenia and the chromosomal region 22q12-q13. 14-3-3 protein, abundant in the brain, mediates interactions between diverse molecules of biological activities; its gene was recently mapped to chromosome 22q12.1-q13.1. We therefore investigated allele frequencies of a variable number of tandem repeat (VNTR) in the 5'-noncoding region of the 14-3-3 eta chain gene in controls and schizophrenics. The frequencies of the two-repeat allele were significantly higher (P < 0.05) in the schizophrenics, and particularly in those with onset before age 22 (early-onset schizophrenics, P < 0.02), than in the controls. The odds ratio was significantly increased in the early-onset schizophrenics homozygous for the two-repeat allele (OR = 3.3, 95% CI = 1.1-9.7). The 14-3-3 eta chain gene is a potential susceptibility gene for schizophrenia, and particularly for early-onset schizophrenia.     

PRODH mutations and hyperprolinemia in a subset of schizophrenic patients

The increased prevalence of schizophrenia among patients with the 22q11 interstitial deletion associated with DiGeorge syndrome has suggested the existence of a susceptibility gene for schizophrenia within the DiGeorge syndrome chromosomal region (DGCR) on 22q11. Screening for genomic rearrangements of 23 genes within or at the boundaries of the DGCR in 63 unrelated schizophrenic patients and 68 unaffected controls, using quantitative multiplex PCR of short fluorescent fragments (QMPSF), led us to identify, in a family including two schizophrenic subjects, a heterozygous deletion of the entire PRODH gene encoding proline dehydrogenase. This deletion was associated with hyperprolinemia in the schizophrenic patients. In addition, two heterozygous PRODH missense mutations (L441P and L289M), detected in 3 of 63 schizophrenic patients but in none among 68 controls, were also associated with increased plasma proline levels. Segregation analysis within the two families harboring respectively the PRODH deletion and the L441P mutation showed that the presence of a second PRODH nucleotide variation resulted in higher levels of prolinemia. In two unrelated patients suffering from severe type I hyperprolinemia with neurological manifestations, we identified a homozygous L441P PRODH mutation, associated with a heterozygous R453C substitution in one patient. These observations demonstrate that type I hyperprolinemia is present in a subset of schizophrenic patients, and suggest that the genetic determinism of type I hyperprolinemia is complex, the severity of hyperprolinemia depending on the nature and number of hits affecting the PRODH locus.     

Tandem pore domain K+‐channel TASK‐3 (KCNK9) and idiopathic absence epilepsies

Recently, the gene coding for the tandem pore domain K⁺‐channel TASK‐3 (KCNK9) has been localized to the chromosomal region 8q24. Because mutations in ion channel genes have been recognized as an important factor in the etiology of abnormal neuronal excitability, TASK‐3 is an interesting candidate gene for epilepsies linked to 8q24. We therefore performed a mutation analysis of the TASK‐3 gene in 65 patients with childhood and juvenile absence epilepsy. Only one silent nucleotide exchange (636C/T) was detected in exon 2 of the TASK‐3 coding region. No evidence for an allelic association was found between the exon 2 polymorphism and absence epilepsy. Accordingly, genetic variation of the TASK‐3 coding region does not play a major role in the etiology of idiopathic absence epilepsies. © 2002 Wiley‐Liss, Inc.     

Systematic screening for mutations in the human serotonin 1F receptor gene in patients with bipolar affective disorder and schizophrenia

Using single strand conformational analysis we screened the complete coding sequence of the serotonin 1F (5-HT_1F) receptor gene for the presence of DNA sequence variation in a sample of 137 unrelated individuals including 45 schizophrenic patients, 46 bipolar patients, as well as 46 healthy controls. We detected only three rare sequence variants which are characterized by single base pair substitutions, namely a silent T→A transversion in the third position of codon 261 (encoding isoleucine), a silent C→T transition in the third position of codon 176 (encoding histidine), and a C→T transition in position −78 upstream from the start codon. The lack of significant mutations in patients suffering from schizophrenia and bipolar affective disorder indicates that the 5-HT_1F receptor is not commonly involved in the etiology of these diseases. © 1996 Wiley-Liss, Inc.     

Novel mutations in the promoter and coding region of the human 5-HT1A receptor gene and association analysis in schizophrenia

Dysfunction of serotonin systems has been implicated in schizophrenia. In the present study, the human 5-HT_1A receptor gene containing the 5′ untranslated region was screened in order to detect genetic variations, through which alteration of protein function or level of expression might contribute to schizophrenia. Genomic DNAs were isolated from whole-blood samples of 61 unrelated schizophrenic patients and 100 healthy controls. Genetic variations were screened systematically by single-strand conformational polymorphism (SSCP) analysis, followed by direct sequencing of polymerase chain reaction (PCR) product as well as restriction fragment-length polymorphism (RFLP). The novel mutations (−51T → C, −152C → G, −321G → C, −480delA, and −581C → A) were found in the 5′ untranslated region. Furthermore, we found a novel missense mutation (Gly272Asp) in the coding region in addition to the mutations (Pro16Leu, 294G → A, and 549C → T) reported previously. No significant differences in genotype frequencies as well as allele frequencies were found between patients and controls. Our data provided no evidence of association between schizophrenia and the variants in the 5′ untranslated region as well as the coding region of the human 5-HT_1A receptor gene. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 81:434–439, 1998. © 1998 Wiley-Liss, Inc.     

Mutation analysis of synapsin III gene in schizophrenia

Synapsin III is a new synapsin family gene with the putative function of synaptogenesis regulation and neurotransmitter release in the brain. The gene was mapped to 22q12-q13, a schizophrenia susceptible region gene as suggested by several linkage studies. Hence, the synapsin III gene is considered a candidate gene of schizophrenia. We systematically sequenced the protein coding and 5'-promoter regions of the synapsin III gene to look for mutations in 62 Han Chinese schizophrenic patients from Taiwan with positive family history. Further case-control association study was performed among 163 patients and 151 controls using the genetic polymorphic markers identified from these 62 patients. Three single nucleotide polymorphisms (SNPs) were identified: g.-631C > G and g.-196G>A at 5'-promoter region, and g.69G>A at exon 1. Besides, no other mutations were identified in these patients. The g.69G>A polymorphism does not alter the amino acid threonine at codon 23 (ACG>ACA). Further case-control association studies also did not find significant differences of genotype or allele frequency distributions of these three polymorphisms between 163 patients and 151 non-psychotic comparison individuals. Hence, our data are not in favor of a large effect of synapsin III gene in the pathogenesis of schizophrenia.     

Recurrent mutation of JAK3 in T‐cell prolymphocytic leukemia

T‐cell prolymphocytic leukemia (T‐PLL) is an aggressive post‐thymic T‐cell malignancy characterized by the recurrent inv(14)(q11q32)/t(14;14)(q11;q32) or t(X;14)(q28;q11) leading to activation of either the TCL1 or MTCP1 gene, respectively. However, these primary genetic events are insufficient to drive leukemogenesis. Recently, activating mutations in JAK3 have been identified in other T‐cell malignancies. Since JAK3 is essential for T‐cell maturation, we analyzed a cohort of 32 T‐PLL patients for mutational hot spots in the JAK3 gene using a step‐wise screening approach. We identified 14 mutations in 11 of 32 patients (34%). The most frequently detected mutation in our cohort was M511I (seen in 57% of cases) previously described as an activating change in other T‐cell malignancies. Three patients carried two mutations in JAK3. In two patients M511I and R657Q were simultaneously detected and in another patient V674F and V678L. In the latter case we could demonstrate that the mutations were on the same allele in cis. Protein modeling and homology analyses of mutations present in other members of the JAK family suggested that these mutations likely activate JAK3, possibly by disrupting the activation loop and the interface between N and C lobes, increasing the accessibility of the catalytic loop. In addition, four of the 21 patients lacking a JAK3 point mutation presented an aberrant karyotype involving the chromosomal band 19p13 harboring the JAK3 locus. The finding of recurrent activating JAK3 mutations in patients with T‐PLL could enable the use of JAK3 inhibitors to treat patients with this unfavorable malignancy who otherwise have a very poor prognosis. © 2014 Wiley Periodicals, Inc.     

C283Y mutation and other C‐terminal nucleotide changes in the γ‐sarcoglycan gene in the Bulgarian gypsy population

Sarcoglycanopathies, affecting the dystrophin‐associated sarcoglycan (SG) complex, are a heterogeneous group of neuromuscular disorders. A subgroup of these disorders, limb‐girdle muscular dystrophy type 2C (LGMD2C) is an autosomal recessive disorder, clinically manifested as an early onset, severe Duchenne‐like muscular dystrophy. LGMD2C is caused by mutations in the γ‐SG gene, localized on 13q12. Recently, a number of mutations have been described in that gene, among which C283Y, a “private” Gypsy mutation (eight codons before the 3′ end of the gene) is detected. In this article, we report on a single‐strand conformation polymorphism (SSCP) method for fast C283Y mutation detection, using direct dry blood spot amplification. The method permits a large number of samples to be easily screened. To check heterozygote carriers of C283Y mutation among Gypsy population in Bulgaria, the SSCP analysis was applied on 400 Gypsy newborns from northeast Bulgaria. Our results show 2.25% of heterozygosity, which means that 1 in 50 Gypsies carries the mutation. Moreover, new SSCP migration patterns were detected that revealed two polymorphisms still unavailable in the literature. One of these changes was 984G→A, leading to substitution of conserved serine at position 287 with asparagine and the second one is 1049C→G at the 3′ UTR (untranslated region). The present data could help the understanding the role of these sequences for the protein function. Hum Mutat 14:40–44, 1999. © 1999 Wiley‐Liss, Inc.     

Synapsin III gene polymorphisms and schizophrenia

Synapsins are synaptic vesicle-associated phosphoproteins and are thought to play crucial roles in synaptogenesis and neurotransmitter release. Synaptic abnormalities have been reported in the pathophysiology of schizophrenia. In addition, the synapsin III gene, a member of the synapsin gene family, has been located at 22q12-13, which has been suggested as a potential susceptibility locus for schizophrenia. We investigated a genetic association between schizophrenia and the synapsin III gene polymorphisms (-631C/G and -196G/A) in 160 schizophrenic patients and 153 controls. No significant positive association between either polymorphism and schizophrenia was observed. Furthermore, no significant association was observed between either polymorphism and the diagnostic subtypes. Our results suggested that the synapsin III gene polymorphisms do not confer increased susceptibility to schizophrenia.     

Ten novel HMGCL mutations in 24 patients of different origin with 3‐hydroxy‐3‐methyl‐glutaric aciduria

3‐Hydroxy‐3‐methylglutaric aciduria is a rare autosomal recessive genetic disorder that affects ketogenesis and L‐leucine catabolism. The clinical acute symptoms include vomiting, convulsions, metabolic acidosis, hypoketotic hypoglycaemia and lethargy. To date, 33 mutations in 100 patients have been reported in the HMGCL gene. In this study 10 new mutations in 24 patients are described. They include: 5 missense mutations: c.109G>A, c.425C>T, c.521G>A, c.575T>C and c.598A>T, 2 nonsense mutations: c.242G>A and c.559G>T, one small deletion: c.853delC, and 2 mutations in intron regions: c.497+4A>G and c.750+1G>A. Two prevalent mutations were detected, 109G>T (E37X) in 38% of disease alleles analyzed and c.504_505delCT in 10% of them. Although patients are mainly of European origin (71%) and mostly Spanish (54%), the group is ethnically diverse and includes, for the first time, patients from Pakistan, Palestine and Ecuador. We also present a simple, efficient method to express the enzyme and we analyze the possible functional effects of missense mutations. The finding that all identified missense mutations cause a >95% decrease in the enzyme activity, indicates that the disease appears only in very severe genotypes.” © 2009 Wiley‐Liss, Inc.     

A second independent Tyr168Cys mutation in the tissue inhibitor of metalloproteinases-3 (TIMP3) in Sorsby''s fundus dystrophy.

Sorsby's fundus dystrophy (SFD) is a rare autosomal dominant macular disorder with age of onset usually in the fourth decade. It is characterised by loss of central vision owing to subretinal neovascularisation and disciform macular degeneration. In an effort to identify the SFD gene, the disease locus was first mapped to chromosome 22q13-qter by genetic linkage analysis, the same chromosomal region as the gene encoding the tissue inhibitor of metalloproteinases-3 (TIMP3). Subsequently, two separate mutations in TIMP3 were found in affected members of two unrelated SFD pedigrees (Tyr168Cys and Ser181Cys). More recently, two additional SFD related mutations, Ser156Cys and Gly167Cys, have provided further confirmation that heterozygous mutations in TIMP3 are causally responsible for the SFD phenotype. We now report the occurrence of the Tyr168Cys mutation in an SFD patient of Austrian descent and show that this mutation found earlier in an American SFD family arose independently. The new findings add to an emerging pattern of SFD mutations which all seem to affect the C-terminal region of the mature TIMP3 protein. In addition, all known mutations cause a change of an amino acid to a cysteine residue. This suggests a critical role for the additional C-terminal free thiol group in SFD pathogenesis.     

Novel polymorphisms of the human cholecystokinin a receptor gene: An association analysis with schizophrenia

The cholecystokinin A receptor (CCK‐AR) modulates CCK‐stimulated dopamine release in the posterior nucleus accumbens, and its gene is mapped to 4p15.2‐15.1 with the dopamine receptor 5 (DR5) gene. We speculated that alterations in the CCK‐AR lead to an increase in dopamine release, which may in turn constitute a predisposition in schizophrenia. We investigated genetic variations in the promoter region and the coding region of the CCK‐AR gene. An association analysis was conducted between 83 unrelated schizophrenic patients and 80 healthy controls. Novel polymorphisms (201A→G, 246G→A in the promoter region, 1260T→A, 1266T→C in intron 1 within the 3′ mRNA splice acceptor site consensus sequence, and Leu306Leu in exon 5) were found in addition to the variants (608G→A in intron 1, 3849C→T [Ile296Ile] in exon 5) reported previously. Significant differences were found in the allele frequencies of the 201A→G nucleotide substitution in the promoter region between patients and controls (P = 0.0181, odds ratio: 1.972, after Bonferroni correction: P = 0.0543). These differences were also found between the patients with paranoid type and controls (P = 0.0274, odds ratio = 3.667, after Bonferroni correction: P = 0.0822). Our analyses suggest that the 201A allele frequency was higher in the schizophrenic group, especially in the paranoid type, than in the control group at a rate that was not quite significant after Bonferroni correction. Am J. Med Genet. (Neuropsychiatr. Genet.) 96:141–145, 2000. © 2000 Wiley‐Liss, Inc.     

Report from the Maryland epidemiology schizophrenia linkage study: No evidence for linkage between schizophrenia and a number of candidate and other genomic regions using a complex dominant model

Our collaborative group has undertaken a linkage study of schizophrenia, using a systematic sample of patients admitted to Maryland hospitals. An initial sample of 39 families, each having two or more affecteds, was available for genotyping candidate genes, candidate regions, and highly polymorphic markers randomly distributed throughout the genome. We used a single complex dominant model (with a disease gene frequency of 0.005 and age-dependent penetrance for affected phenotype: for under 35, penetrance = .45; for 35 and older, penetrance = .85). We report here 130 markers, which met the exclusion criteria of LOD score <?2.00 at theta >0.01 in at least 10 informative families, and no evidence for heterogeneity. We also report here markers that were tested as candidates for linkage to the schizophrenic phenotype. They were selected based on the following criteria: (a) proximity to reported chromosomal rearrangements (both 5q and 11q), (b) suggestions of linkage from other families (5q), or (c) presence of a candidate gene (5q, 11q, 3q: Dopamine receptors 1, 2, and 3, respectively). We also tested for mutations of codon 717 in exon 17 of the amyloid precursor protein (APP) gene and were unable to detect the C to T substitution in our schizophrenic group. © 1994 Wiley-Liss, Inc.     

深圳地区β-珠蛋白生成障碍性贫血基因突变分析

目的对深圳地区β-珠蛋白生成障碍性贫血患者的β-珠蛋白基因序列进行分析,了解深圳地区人群β-珠蛋白基因的突变类型。方法收集100例深圳地区β-珠蛋白生成障碍性贫血患者的外周血并抽提基因组DNA,通过聚合酶链反应扩增全长β-珠蛋白基因,经DNA测序确定β-珠蛋白基因的突变类型。结果在89例深圳地区β-珠蛋白生成障碍性贫血患者中,我们在β-珠蛋白基因中共发现7种突变,以突变频率高低依次为IVS-Ⅱ-654(C→T)、Codon17(A→T)、Codon41/42(-TTCT)、Codon71/72(+A)、Codon27/28(+C)、Codon43(G→T)、-28(A→G)。剩余11例临床诊断的β-珠蛋白生成障碍性贫血患者的β-珠蛋白基因未检出突变。结论在深圳地区人群中IVS-Ⅱ-654(C→T)、Codon17(A→T)和Codon41/42(-TTCT)为β-珠蛋白基因的常见突变。不排除未检出突变患者存在β-珠蛋白基因座控制区存在突变,这将给产前诊断带来困难。     

Genome‐wide significant schizophrenia risk variation on chromosome 10q24 is associated with altered cis‐regulation of BORCS7, AS3MT,and NT5C2 in the human brain

Chromosome 10q24.32‐q24.33 is one of the most robustly supported risk loci to emerge from genome‐wide association studies (GWAS) of schizophrenia. However, extensive linkage disequilibrium makes it difficult to distinguish the actual susceptibility gene(s) at the locus, limiting its value for improving biological understanding of the condition. In the absence of coding changes that can account for the association, risk is likely conferred by altered regulation of one or more genes in the region. We, therefore, used highly sensitive measures of allele‐specific expression to assess cis‐regulatory effects associated with the two best‐supported schizophrenia risk variants (SNP rs11191419 and indel ch10_104957618_I/rs202213518) on the primary positional candidates BORCS7, AS3MT, CNNM2, and NT5C2 in the human brain. Heterozygosity at rs11191419 was associated with increased allelic expression of BORCS7 and AS3MT in the fetal and adult brain, and with reduced allelic expression of NT5C2 in the adult brain. Heterozygosity at ch10_104957618_I was associated with reduced allelic expression of NT5C2 in both the fetal and adult brain. Comparisons between cDNA ratios in heterozygotes and homozygotes for the risk alleles indicated that cis‐effects on NT5C2 expression in the adult dorsolateral prefrontal cortex could be largely accounted for by genotype at these two risk variants. While not excluding effects on other genes in the region, this study implicates altered neural expression of BORCS7, AS3MT, and NT5C2 in susceptibility to schizophrenia arising from genetic variation at the chromosome 10q24 locus. © 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc.