Reka Kovacs-Nagy

Association Between Hypnotizability and the Catechol-O-Methyltransferase (COMT) Polymorphism

Abstract Previous studies implicate involvement of dopaminergic systems in hypnotizability and report association with the COMT Val158Met single nucleotide polymorphism (SNP, rs4680) demonstrating the Val/Met heterozygotes as the most hypnotizable group using the Stanford Hypnotic Susceptibility Scale. This study replicates that association using an independent sample of 127 healthy Hungarian young adults and the Waterloo-Stanford Group C Scale of Hypnotic Susceptibility. Significant association (p = .016) was found between the COMT genotypes and hypnotizability, with a clear additive effect of the Val allele: Hypnotizability scores were highest in Val/Val (5.9), intermediate in Val/Met (4.7), and lowest in Met/Met (4.1). Differences between these results and those of previous studies support recent findings suggesting an inverted-U-shaped relation between dopamine level in the prefrontal cortex and cognitive functioning. The present study replicates association of COMT Val158Met SNP and hypnotizability and stresses the importance of mediating factors, such as group vs. individual inductions.

Association of Impulsivity and Polymorphic MicroRNA-641 Target Sites in the SNAP-25 Gene

Impulsivity is a personality trait of high impact and is connected with several types of maladaptive behavior and psychiatric diseases, such as attention deficit hyperactivity disorder, alcohol and drug abuse, as well as pathological gambling and mood disorders. Polymorphic variants of the SNAP-25 gene emerged as putative genetic components of impulsivity, as SNAP-25 protein plays an important role in the central nervous system, and its SNPs are associated with several psychiatric disorders. In this study we aimed to investigate if polymorphisms in the regulatory regions of the SNAP-25 gene are in association with normal variability of impulsivity. Genotypes and haplotypes of two polymorphisms in the promoter (rs6077690 and rs6039769) and two SNPs in the 3′ UTR (rs3746544 and rs1051312) of the SNAP-25 gene were determined in a healthy Hungarian population (N = 901) using PCR–RFLP or real-time PCR in combination with sequence specific probes. Significant association was found between the T–T 3′ UTR haplotype and impulsivity, whereas no association could be detected with genotypes or haplotypes of the promoter loci. According to sequence alignment, the polymorphisms in the 3′ UTR of the gene alter the binding site of microRNA-641, which was analyzed by luciferase reporter system. It was observed that haplotypes altering one or two nucleotides in the binding site of the seed region of microRNA-641 significantly increased the amount of generated protein in vitro. These findings support the role of polymorphic SNAP-25 variants both at psychogenetic and molecular biological levels.

Glycogen synthase kinase 3 beta gene structural variants as possible risk factors of bipolar depression

The glycogen synthase kinase 3B (GSK3B) is an important target protein of several antidepressants, such as lithium, a mood stabilizer. Recent studies associated structural variations of the GSK3B gene to bipolar disorder (BP), although replications were not conclusive. Here we present data on copy number variations (CNVs) of the GSK3B gene probing the 9th exon region in 846 individuals (414 controls, 172 patients with major depressive disorder (MDD) and 260 with BP). A significant accumulation (odds ratio: 5.5, P = 0.00051) of the amplified exon 9 region was found in patients (22 out of 432) compared to controls (4 of 414). Analyzing patient subgroups, GSK3B structural variants were found to be risk factors of BP particularly (P = 0.00001) with an odds ratio of 8.1 while no such effect was shown in the MDD group. The highest odds (19.7 ratio) for bipolar disorder was observed in females with the amplified exon 9 region. A more detailed analysis of the identified GSK3B CNV by a set of probes covering the GSK3B gene and the adjacent NR1I2 and C3orf15 genes showed that the amplified sequences contained 3′ (downstream) segments of the GSK3B and NR1I2 genes but none of them involved the C3orf15 gene. Therefore, the copy number variation of the GSK3B gene could be described as a complex set of structural variants involving partial duplications and deletions, simultaneously. In summary, here we confirmed significant association of the GSK3B CNV and bipolar disorder pointing out that the copy number and extension of the CNV varies among individuals.

Association of aggression with a novel microRNA binding site polymorphism in the wolframin gene.

Rare mutations in the WFS1 gene lead to Wolfram syndrome, a severe multisystem disorder with progressive neurodegeneration and diabetes mellitus causing life‐threatening complications and premature death. Only a few association studies using small clinical samples tested the possible effects of common WFS1 gene variants on mood disorders and suicide, the non‐clinical spectrum has not been studied yet. Self‐report data on Aggression, Impulsiveness, Anxiety, and Depression were collected from a large (N = 801) non‐psychiatric sample. Single nucleotide polymorphisms (SNPs) were selected to provide an adequate coverage of the entire WFS1 gene, as well as to include putative microRNA binding site polymorphisms. Molecular analysis of the assumed microRNA binding site variant was performed by an in vitro reporter‐gene assay of the cloned 3′ untranslated region with coexpression of miR‐668. Among the 17 WFS1 SNPs, only the rs1046322, a putative microRNA (miR‐668) binding site polymorphism showed significant association with psychological dimensions after correction for multiple testing: those with the homozygous form of the minor allele reported higher aggression on the Buss–Perry Aggression Questionnaire (P = 0.0005). Functional effect of the same SNP was also demonstrated in a luciferase reporter system: the minor A allele showed lower repression compared to the major G allele, if co‐expressed with miR‐668. To our knowledge, this is the first report describing a microRNA binding site polymorphism of the WFS1 gene and its association with human aggression based on a large, non‐clinical sample.

Haplotyping of putative microRNA-binding sites in the SNAP-25 gene.

Synaptosomal‐associated protein 25 (SNAP‐25) plays a crucial role in exocitosis. Single nucleotide polymorphisms (rs3746544 and rs1051312) in the 3′ un‐translated region of the SNAP‐25 gene have been described to be in association with attention‐deficit hyperactivity disorder. As the disease affects millions of children world‐wide, understanding the genetic background of attention‐deficit hyperactivity disorder is of crucial importance. Efficient and reliable PCR‐RFLP protocols were elaborated for the genotyping of the rs3746544 and rs1051312 SNPs employing a high‐throughput capillary electrophoresis method for fragment analysis. A novel real‐time PCR‐based technique was used applying sequence specific TaqMan probes to haplotype the two SNPs, and the G–C haplotype could not be detected in a large Caucasian population (N=1376). These findings have been confirmed by molecular biology tools as well as by the PHASE Bayesian computational approach. In silico analyses have suggested that the two SNPs might alter microRNA binding and thus have an effect on SNAP‐25 production. We have demonstrated that this biological information can be revealed only by direct haplotype analysis emphasizing the importance of our novel molecular haplotye analysis protocol. Results of the study of the two SNPs might shed light on the association of SNAP‐25 variants and pathological phenotypes at the molecular level.

Combined Respiratory Chain Deficiency and UQCC2 Mutations in Neonatal Encephalomyopathy: Defective Supercomplex Assembly in Complex III Deficiencies

Vertebrate respiratory chain complex III consists of eleven subunits. Mutations in five subunits either mitochondrial (MT-CYB) or nuclear (CYC1, UQCRC2, UQCRB, and UQCRQ) encoded have been reported. Defects in five further factors for assembly (TTC19, UQCC2, and UQCC3) or iron-sulphur cluster loading (BCS1L and LYRM7) cause complex III deficiency. Here, we report a second patient with UQCC2 deficiency. This girl was born prematurely; pregnancy was complicated by intrauterine growth retardation and oligohydramnios. She presented with respiratory distress syndrome, developed epileptic seizures progressing to status epilepticus, and died at day 33. She had profound lactic acidosis and elevated urinary pyruvate. Exome sequencing revealed two homozygous missense variants in UQCC2, leading to a severe reduction of UQCC2 protein. Deficiency of complexes I and III was found enzymatically and on the protein level. A review of the literature on genetically distinct complex III defects revealed that, except TTC19 deficiency, the biochemical pattern was very often a combined respiratory chain deficiency. Besides complex III, typically, complex I was decreased, in some cases complex IV. In accordance with previous observations, the presence of assembled complex III is required for the stability or assembly of complexes I and IV, which might be related to respirasome/supercomplex formation.

A De Novo Missense Variant in POU3F2 Identified in a Child with Global Developmental Delay

&NA; Many genetic and nongenetic causes for developmental delay in childhood could be identified. Often, however, the molecular basis cannot be elucidated. As next‐generation sequencing is becoming more frequently available in a diagnostic context, an increasing number of genetic variations are found as causative in children with developmental delay. We performed trio exome sequencing in a girl with developmental delay and minor dysmorphological features. Using a filter for de novo variants, the heterozygous missense variant c.812A>T, p.(Glu217Val) was found in the candidate gene POU3F2 in our patient. POU3F2 plays an important role in neuronal differentiation and hormonal regulation. To date, it has not been associated with monogenic disorders. Studies on Pou3f2 knockout mice highlighted the importance of this protein in the development of the brain. Furthermore, microdeletions with an overlapping region including only POU3F2 and FBXL4 were linked to developmental delay in six unrelated families. Therefore, POU3F2 is a strong candidate gene for developmental delay, although functional assays proving this assumption still have to be done.

Identification of a Novel Heterozygous De Novo 7-bp Frameshift Deletion in PBX1 by Whole-Exome Sequencing Causing a Multi-Organ Syndrome Including Bilateral Dysplastic Kidneys and Hypoplastic Clavicles

Introduction Congenital anomalies of the kidney and urinary tract (CAKUT) represent the primary cause of chronic kidney disease in children. Many genes have been attributed to the genesis of this disorder. Recently, haploinsufficiency of PBX1 caused by microdeletions has been shown to result in bilateral renal hypoplasia and other organ malformations. Materials and methods Here, we report on a 14-year-old male patient with congenital bilateral dysplastic kidneys, cryptorchidism, hypoplastic clavicles, developmental delay, impaired intelligence, and minor dysmorphic features. Presuming a syndromic origin, we performed SNP array analysis to scan for large copy number variations (CNVs) followed by whole-exome sequencing (WES). Sanger sequencing was done to confirm the variant’s de novo status. Results SNP array analysis did not reveal any microdeletions or -duplications larger than 50 or 100 kb, respectively. WES identified a novel heterozygous 7-bp frameshift deletion in PBX1 (c.413_419del, p.Gly138Valfs*40) resulting in a loss-of-function. The de novo status could be confirmed by Sanger sequencing. Discussion By WES, we identified a novel heterozygous de novo 7-bp frameshift deletion in PBX1. Our findings expand the spectrum of causative variants in PBX1-related CAKUT. In this case, WES proved to be the apt technique to detect the variant responsible for the patient’s phenotype, as single gene testing is not feasible given the multitude of genes involved in CAKUT and SNP array analysis misses rare single-nucleotide variants and small Indels.