Role of BRCA1 in Neuronal Death in Alzheimer's Disease.

Oxidative damage of DNA has recently been indicated as one of the strong pathogenic agent in Alzheimer's disease (AD). Oxidative stress induces numerous signaling pathways, including DNA damage response (DDR), associated with the breast cancer type 1 susceptibility protein (BRCA1) protein, known to date from numerous reports in the cancer field. In this Viewpoint, we discuss the latest discoveries related to the role of BRCA1 in the death of neurons in AD. We underline the role of BRCA1 in the development of neurons and speculate on the consequences of BRCA1 dysfunction in the dying brain. In general, this Viewpoint is in a line with several recent reports on the processes and players common at the molecular and genetic level for neurodegenerative and cancerous diseases.

DNA methylation in ELOVL2 and C1orf132 correctly predicted chronological age of individuals from three disease groups.

Improving accuracy of the available predictive DNA methods is important for their wider use in routine forensic work. Information on age in the process of identification of an unknown individual may provide important hints that can speed up the process of investigation. DNA methylation markers have been demonstrated to provide accurate age estimation in forensics, but there is growing evidence that DNA methylation can be modified by various factors including diseases. We analyzed DNA methylation profile in five markers from five different genes (ELOVL2, C1orf132, KLF14, FHL2, and TRIM59) used for forensic age prediction in three groups of individuals with diagnosed medical conditions. The obtained results showed that the selected age-related CpG sites have unchanged age prediction capacity in the group of late onset Alzheimer's disease patients. Aberrant hypermethylation and decreased prediction accuracy were found for TRIM59 and KLF14 markers in the group of early onset Alzheimer's disease suggesting accelerated aging of patients. In the Graves' disease patients, altered DNA methylation profile and modified age prediction accuracy were noted for TRIM59 and FHL2 with aberrant hypermethylation observed for the former and aberrant hypomethylation for the latter. Our work emphasizes high utility of the ELOVL2 and C1orf132 markers for prediction of chronological age in forensics by showing unchanged prediction accuracy in individuals affected by three diseases. The study also demonstrates that artificial neural networks could be a convenient alternative for the forensic predictive DNA analyses.

Genetic variants associated with physical and mental characteristics of the elite athletes in the Polish population.

The aim of the study was to assess whether selected genetic variants are associated with elite athlete performance in a group of 413 elite athletes and 451 sedentary controls. Polymorphisms in ACE, ACTN3, AGT, NRF-2, PGC1A, PPARG, and TFAM implicated in physical performance traits were analyzed. Additionally, polymorphisms in CHRNB3 and FAAH coding for proteins modulating activity of brain's emotion centers were included. The results of univariate analyses indicated that the elite athletic performance is associated with four polymorphisms: ACE (rs4341, P = 0.0095), NRF-2 (rs12594956, P = 0.011), TFAM (rs2306604, P = 0.049), and FAAH (rs324420, P = 0.0041). The multivariate analysis adjusted for age and gender confirmed this association. The higher number of ACE D alleles (P = 0.0021) and the presence of NRF-2 rs12594956 A allele (P = 0.0067) are positive predictors, whereas TFAM rs2306604 GG genotype (P = 0.031) and FAAH rs324420 AA genotype (P = 0.0084) negatively affect the elite athletic performance. The CHRNB3 variant (rs4950, G allele) is significantly more frequent in the endurance athletes compared with the power ones (P = 0.025). Multivariate analysis demonstrated that the presence of rs4950 G allele contributes to endurance performance (P = 0.0047). Our results suggest that genetic inheritance of psychological traits should be taken into consideration while trying to decipher a genetic profile of top athletic performance.

Parkinson's disease-related gene variants influence pre-mRNA splicing processes.

We have analyzed the impact of Parkinson's disease (PD)-related genetic variants on splicing using dedicated minigene assays. Out of 14 putative splicing variants in 5 genes (PINK1, [PTEN induced kinase 1]; LRPPRC, [leucine-rich pentatricopeptide repeat containing protein]; TFAM, [mitochondrial transcription factor A]; PARK2, [parkin RBR E3 ubiquitin protein ligase]; and HSPA9, [heat shock protein family A (Hsp70) member 9]), 4 LRPPRC variants, (IVS32-3C>T, IVS35+14C>T, IVS35+15C>T, and IVS9+30A>G) influenced, pre-messenger RNA splicing by modulating the inclusion of the respective exons. In addition, 1-Methyl-4-phenylpyridinium ion-induced splicing changes of endogenous LRPPRC messenger RNA, reproduced the effect of the LRPPRC IVS35+14C>T mutation. Using silencing and overexpression methods, we show that LRPPRC exon 33 splicing is negatively regulated by heterogeneous nuclear ribonucleoprotein A1 both in a minigene and endogenous context. Furthermore, exon 33 exclusion due to PD-associated mutation IVS32-3C>T or heterogeneous nuclear ribonucleoprotein A1 overexpression and exon 35 exclusion due to IVS35+14C>T can be rescued by co-expression of modified U1 small nuclear RNAs, providing a potentially useful therapeutic strategy. Our results indicate for the first time that LRPPRC intronic variants can affect normal splicing of this gene and may influence disease risk in PD and related disorders.

Mitochondrial DNA variation is associated with elite athletic status in the Polish population.

There is mounting evidence that genetic factors located in mitochondrial and nuclear genomes influence sport performance. Certain mitochondrial haplogroups and polymorphisms were associated with the status of elite athlete, especially in endurance performance. The aim of our study was to assess whether selected mitochondrial DNA (mtDNA) and nuclear DNA variants are associated with elite athlete performance in a group of 395 elite Polish athletes (213 endurance athletes and 182 power athletes) and 413 sedentary controls. Our major finding was that the mtDNA haplogroup H and HV cluster influence endurance performance at the Olympic/World Class level of performance (P = 0.018 and P = 0.0185, respectively). We showed that two polymorphisms located in the mtDNA control region were associated with achieving the elite performance level either in the total athlete's group as compared with controls (m.16362C, 3.8% vs 9.2%, respectively, P = 0.0025, odds ratio = 0.39, 95% confidence interval: 0.21-0.72), or in the endurance athletes as compared with controls (m.16080G, 2.35% vs 0%, respectively, P = 0.004). Our results indicate that mtDNA variability affects the endurance capacity rather than the power one. We also propose that mtDNA haplogroups and subhaplogroups, as well as individual mtDNA polymorphisms favoring endurance performance, could be population-specific, reflecting complex cross-talk between nuclear and mitochondrial genomes.

Interleukin-1 gene -511 CT polymorphism and the risk of Alzheimer's disease in a Polish population.

Interleukin-1 is a potent proinflammatory cytokine involved in the pathophysiology of Alzheimer's disease (AD). We genotyped IL-1beta (-511 C/T) and the apolipoprotein E (APOE) common polymorphisms in a large case-controlled study in a Polish population. We included 332 patients with late-onset AD and 220 controls without any neurological deficit, cognitive complaints and history of neurological diseases, aged > or = 65 years. The distribution of the IL-1beta (-511 C/T) genotypes was similar to that in the controls (AD: C/C = 45.8%, C/T = 44.6%, T/T = 9.6% vs. controls: C/C = 53.9%, C/T = 38.3%, T/T = 7.3%, p > 0.05). Our study confirms previous reports that APOE epsilon4 is strongly related to the risk of AD (odds ratio = 6.60, 95% confidence interval 4.19-10.41). APOE status did not affect the distribution of the studied IL-1beta polymorphism. The IL-1beta (-511 C/T) polymorphism is not a risk factor for late-onset AD in a Polish population.

Maternal tetrahydrobiopterin deficiency: the course of two pregnancies and follow-up of two children in a mother with 6-pyruvoyl-tetrahydropterin synthase deficiency.

No reports are available about the course of pregnancies in women with tetrahydrobiopterin (BH(4)) deficiencies or the effects of treatment with BH(4), L-dopa/carbidopa and 5-hydroxytryptophan (5-OHTrp) on fetal development. We present for the first time the case of a mother with late-diagnosed mild form of 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency, the course of her two subsequent pregnancies and clinical evaluation with follow-up of two offspring. In both pregnancies neurotransmitter precursors, as well as BH(4) dosages were increased proportionally to the mother's weight gain. To prevent maternal phenylketonuria (MPKU) syndrome, special attention was paid to increasing BH(4) dosages. Both pregnancies were complicated by threatened premature labour, by the mother's nicotinism and additionally, in the first pregnancy, by gestational diabetes mellitus and vaginitis. The first child was born in the 31st week of pregnancy with the symptoms of moderate intrauterine growth retardation (IUGR) and brain malformation in the form of right sided closed-lip schizencephaly with absence of septum pellucidum. Although the girl demonstrates mild left-sided hemiparesis, her psychological development at the age of 8 years is above average. The second child was born in the 37th week of pregnancy without brain anomalies and at the age of 5 years his psychomotor development is appropriate for the age. As the cause of brain malformations resulting in physical impairment in the first child is unknown, more data are essential to verify conclusions about the influence of the mother's BH(4) deficiency and the safety of her treatment for fetal development.

Two polymorphisms of presenilin-2 gene (PSEN2) 5' regulatory region are not associated with Alzheimer's disease (AD) in the Polish population.

Presenilin 2 gene (PSEN2) is one of the causative genes for familial Alzheimer's disease. A delA polymorphism located in PSEN2 promoter was proposed to be a risk factor for early-onset AD. We examined association between AD and PSEN2 polymorphisms located in two 5'UTR regions in group of 217 late-onset AD patients, 109 mild cognitive impairment patients, and 225 non-demented control subjects. No significant differences for genotype and allele distributions of a delA and a novel insAC polymorphisms in the studied groups as compared to controls were observed. Univariate and multivariate risk estimation shows that neither delA, insAC alleles nor the genotypes are risk factors for AD. No significant interaction between the APOE4 and PSEN2 polymorphisms was found. A bioinformatic analysis showed that delA polymorphism influences binding sites of transcription factors involved in the cellular processes related to AD. The rare variants identified in exon 3 of the PSEN2 could have a potential influence on PSEN2 transcript splicing.

Early-onset Alzheimer's disease with a de novo mutation in the presenilin 1 gene.

A 32-year-old woman diagnosed with very rapidly progressing early-onset Alzheimer's disease (EOAD), age of onset 29 years, and S170F mutation in presenilin 1 gene (PSEN1) is presented. Neuroimaging conducted 2 years after the first symptoms was typical for the advanced stage of Alzheimer's disease (AD), showing cortical brain atrophy, particularly within hippocampus, frontal and temporal cortex. The unaffected parents of the proband are not carriers of the mutation. The paternity was confirmed by microsatellite typing, strongly suggesting de novo origin of S170F mutation. In silico modeling of S170F mutation impact on presenilin 1 (PS1) transmembrane structure indicates that the mutation considerably alters putative interactions of PS1 with other proteins within gamma-secretase complex.

Prion protein gene M129 allele is a risk factor for Alzheimer's disease.

Prion protein gene polymorphism M129V represents a known risk factor for Creutzfeldt-Jakob disease. Recently, the meta-analysis revealed that homozygosity at codon 129 is connected with increased risk of Alzheimer's disease (AD). To determine whether M129V polymorphism is a risk factor for AD we analyzed a group of early-onset, and late-onset Polish AD patients. We observed that in LOAD patients there is a statistically significant increase of MM (p=0.0028) and decrease of MV (p=0.0006) genotype frequency, as compared to controls. When both groups were stratified according to APOE4 status, increase of MM and decrease of MV genotype frequency were significant in the LOAD subgroup with no APOE4 (p=0.017, and p=0.018, respectively). In the subgroup with APOE4 allele, only MV genotype frequency was significantly lower, as compared to controls (p=0.035). However, no interaction was found between APOE4 status and M129V polymorphism. We conclude that MM genotype increases LOAD risk in Polish population independently from the APOE4 status.

The -22c/t polymorphism in presenilin 1 gene is not connected with late-onset and early-onset familial Alzheimer's disease in Poland.

The -22c/t polymorphism in the promoter of the presenilin 1 gene is associated with increased risk for Alzheimer's disease (AD) in some populations. It was shown that -22c allele is connected with two-fold decrease in promoter activity. We studied the impact of the polymorphism in groups of Polish late-onset and early-onset AD patients. Our results suggest that -22c/t polymorphism is not connected with AD in Polish population. The -22t allele showed a high degree of linkage disequilibrium with -2797 insertion of 13 bp. An additional -2923g/t polymorphism is also not connected with -22c/t and is not a risk factor for AD.

Different presentations of late-detected phenylketonuria in two brothers with the same R408W/R111X genotype in the PAH gene.

Although the clinical heterogeneity of phenylketonuria (PKU) is well established, some questions about this condition remain. Subjects from the same family who share the same mutations in the phenylalanine hydroxylase (PAH) gene are expected to display similar disease courses, and therefore, when blood phenylalanine (Phe) levels, genotype and dietary treatment are all similar, differences in patient outcomes require additional explanations. The present authors describe two entirely different courses of late-detected PKU in two brothers with the same R408W/R111X genotype in the PAH gene. The older sibling was diagnosed with PKU at the age of 4 years and given treatment. His IQ was 97 at 26 years of age and moderate involvement of periventricular white matter was detected. The younger brother was diagnosed with PKU at the age of 11 months and given treatment. His IQ was < 25 at 22 years of age and severe dysmyelination changes were found by magnetic resonance imaging. The differences in the courses of the disease between these two brothers appear to be related to variations in their blood-brain barriers.

Should newborn mutation scanning for hyperphenylalaninaemia and galactosaemia be implemented? A Polish experience.

OBJECTIVE: To elucidate whether screening for mutations causing hyperphenylalaninaemia (HPA) and classic galactosaemia could provide important, additional information on a clinical phenotype. METHOD: Genotypes that cause disease at the phenylalanine hydroxylase (PAH) gene and galactose-1-phosphate uridyltransferase (GALT) gene in a group of 101 hyperphenylalaninaemic and 77 patients with classic galactosaemia were established. The PAH and GALT mutations were identified in genomic DNA extracted from whole blood leucocytes using single stranded conformational analysis and direct fluorescent sequencing of polymerase chain reaction (PCR) products. RESULTS: Mild HPA and mild phenylketonurea (PKU) were caused by divergent genotypes. In the studied group a total of 26 different mild and intermediate PAH mutations were identified, most of them being rare ones. Classic galactosaemia was caused by two frequent mutations, accounting for 82% of all mutated alleles. CONCLUSIONS: Identification of mild or intermediate mutations causing HPA could provide fast and reliable information about future clinical outcome of a newborn infant. Molecular diagnosis of HPA should be preceded by biochemical analysis and implemented to differentiate mild forms of HPA and cases of ambiguous classification. Because of multiple rare mutations scattered on all exons, scanning of the entire PAH coding sequence could be useful and cost beneficial. Routine genotyping is not proposed in classic phenylketonuria and classic galactosaemia, as it provides limited additional, prospective information on the clinical phenotype.

[Molecular diagnosis of lymphomas and leukaemias]. / Diagnostyka molekularna chloniaków I bialaczek.

In the last years molecular diagnosis has become a routine method m the evaluation of haematological malignancies. Various techniques are used to assess B- and T-cell clonality, chromosomal rearrangements involving protooncogenes, monitoring of minimal residual disease as well as genome wide scanning methods such as comparative genomic hybridization or spectral karyotyping. The review explores some avenues in which molecular techniques can affect patient's retrospective and prospective diagnosis. The major advantages and disadvantages of some of these techniques are described and their place in the scheme of diagnosis and treatment is briefly summarised.

[In search of genetic determinants of obesity].

Common obesity is a multifactorial trait that lies at the interface between the biology of body energy regulation and the environment. Obesity involves genetic predisposition but also metabolic, hormonal, behavioural, social and cultural aspects. According to some estimates 40 to 70 percent of the variation in obesity-related phenotypes is heritable. Mutations in a single gene cause only about 5% of cases. The number of genes and markers associated or linked with human obesity is more than 200. Interactions between multiple genes, environment and human personality, make the search for obesity-related genes especially challenging.

Association between minihaplotypes and mutations at the PAH locus in Polish hyperphenylalaninemic patients.

Hereditary hyperphenylalaninemia (HPA) is a disorder of amino acid metabolism and results from an insufficiency of hepatic phenylalanine hydroxylase (PAH). HPA phenotypes form a spectrum ranging from classical phenylketonuria (PKU) to mild hyperphenylalaninemia (MHP). The phenotypic diversity reflects heterogeneity at the molecular level, and more than 320 different mutations in the PAH gene are known to date. The association of 3 mutations (R408W, IVS10 and A403V) common in different European populations with a variable number tandem repeat (VNTR) and short tandem repeat sites (minihaplotype) in the PAH gene was examined in a group of Polish PKU and MHP patients. Additionally, minihaplotypes were established for another 16 mutations. The presented data support the hypothesis that the R408W/VNTR3/STR238 allele originated among pre-Indo-Europeans on the territory in present-day Lithuania and Belarus. Mutation IVS10nt-11g-->a (IVS10) is strongly associated with VNTR7/STR250 minihaplotype and is possibly of Mediterranean origin.

[Molecular diagnosis: principles, tasks and purposes]. / Diagnostyka molekularna: zasady, zadania, zamierzenia.

Molecular diagnosis is a relatively young discipline and also one of the most dynamic among clinical laboratory sciences. Molecular genetic diagnosis is the detection of pathogenic mutations in DNA and RNA samples prepared from at-risk patients. The paper reviews some problems connected with molecular technicqes, organization of a reference laboratory and quality assurance system.

Parakeratosis variegata: a possible role of environmental hazards?

We report 2 cases of parakeratosis variegata (PV) evolving from lesions beginning with characteristics of ashy dermatosis. Both patients presented with a reticulated, poikilodermatous and hyperpigmented eruption with bizarre coalescent lichenoid papules. Histology showed lichenoid epidermotropic infiltrates, more pronounced in case No. 1, consistent with early malignancy. The course was chronic: after more than 10 years, systemic symptoms were not present. In patient No. 1, a monoclonal T-cell population was detected 12 years after the onset of the disease. Both patients had close contact with fertilizers and insecticides. In patient No. 2, the lesions spontaneously regressed within 3 years after cessation of exposure. PV may be a prelymphomatous stage of mycosis fungoides or some closely related cutaneous T-cell lymphoma and does not always evolve into overt malignancy. Gene rearrangement detection techniques may be helpful in predicting the course of the disease.

[The attempt to identify mutations in TIGR gene in Polish patients with primary open angle glaucoma]. / Próba identyfikacji mutacji w genie TIGR w polskiej populacji chorych na jaskre pierwotna otwartego kata.

PURPOSE: The case work presents studies on the identification of the most frequent TIGR mutations in Polish population with primary open angle glaucoma. The TIGR gene was identified in a GLC1A locus on chromosome 1 (1q) in a family with juvenile primary open angle glaucoma. The gene encodes TIGR protein (trabecular meshwork inducible gluco-corticoid response protein)--trabecular meshwork glucoprotein. MATERIAL AND METHODS: Ophthalmologic examination was performed in twenty subjects with juvenile primary open angle glaucoma. The blood samples were taken for DNA analyses. RESULTS: Neither any mutations nor polymorphic changes in TIGR gene were found. CONCLUSION: Our studies have not identified any mutations in exon 3 of TIGR gene. We cannot exclude, however, that mutations are localised in other exons or regulatory region of examined gene. The questions how many genes, how many mutations of these genes and how often they contribute to glaucoma in general population are still open? These are important questions to answer in order to get closer to understanding extremely complicated aetiology of glaucoma.

Mutations in exon 3 of the PAH gene causing mild hyperphenylalaninemia.

Phenylketonuria (PKU), an autosomal recessive disorder caused by a deficiency of hepatic phenylalanine hydroxylase (PAH), is clinically very heterogeneous. On molecular level more than 350 mutations in the PAH gene are known to date, which in different genotype combinations could account for biochemical and clinical variability. Mutations located in exon 3 coding for a part of the regulatory domain of the PAH enzyme cause classical PKU, mild PKU, and mild hyperphenylalaninemia (MHP). We describe the phenotypic effects of seven mutations in exon 3 of the PAH gene (R68G, R68S, R71H, S87R, P89S, I95F, and A104D). We propose that mutations located between amino acid positions 71 through 94 cause MHP.