TP53 and p21 (CDKN1A) polymorphisms and the risk of systemic lupus erythematosus.

BACKGROUND: The p53 and p21 proteins are important regulators of cell cycle and apoptosis and may contribute to autoimmune diseases, such as systemic lupus erythematosus (SLE). As genetic polymorphisms may cause changes in protein levels and functions, we investigated associations of TP53 and p21 (CDKN1A) polymorphisms (p53 72 G > C-rs1042522; p53 PIN3-rs17878362; p21 31 C > A-rs1801270; p21 70 C > T-rs1059234) with the development of systemic lupus erythematosus (SLE) in a Southeastern Brazilian population. METHODS: Genotyping of 353 female volunteers (cases, n = 145; controls, n = 208) was performed by polymerase chain reaction, restriction fragment length polymorphism and/or DNA sequencing. Associations between TP53 and p21 polymorphisms and SLE susceptibility and clinical manifestations of SLE patients were assessed by logistic regression analysis. RESULTS: Protective effect was observed for the genotype combinations p53 PIN3 A1/A1-p21 31 C/A, in the total study population (OR 0.45), and p53 PIN3 A1/A2-p21 31 C/C, in non-white women (OR 0.28). In Whites, p53 72 C-containing (OR 3.06) and p53 PIN3 A2-containing (OR 6.93) genotypes were associated with SLE risk, and higher OR value was observed for the combined genotype p53 72 G/C-p53 PIN3 A1/A2 (OR 9.00). Further, p53 PIN3 A1/A2 genotype was associated with serositis (OR 2.82), while p53 PIN3 A2/A2 and p53 72 C/C genotypes were associated with neurological disorders (OR 4.69 and OR 3.34, respectively). CONCLUSIONS: Our findings showed that the TP53 and p21 polymorphisms included in this study may have potential to emerge as SLE susceptibility markers for specific groups of patients. Significant interactions of the TP53 polymorphisms with serositis and neurological disorders were also observed in SLE patients.

TP53 and p21 (CDKN1A) polymorphisms and the risk of systemic lupus erythematosus

Abstract Background The p53 and p21 proteins are important regulators of cell cycle and apoptosis and may contribute to autoimmune diseases, such as systemic lupus erythematosus (SLE). As genetic polymorphisms may cause changes in protein levels and functions, we investigated associations of TP53 and p21 (CDKN1A) polymorphisms (p53 72 G > C—rs1042522; p53 PIN3—rs17878362; p21 31 C > A—rs1801270; p21 70 C > T—rs1059234) with the development of systemic lupus erythematosus (SLE) in a Southeastern Brazilian population. Methods Genotyping of 353 female volunteers (cases, n = 145; controls, n = 208) was performed by polymerase chain reaction, restriction fragment length polymorphism and/or DNA sequencing. Associations between TP53 and p21 polymorphisms and SLE susceptibility and clinical manifestations of SLE patients were assessed by logistic regression analysis. Results Protective effect was observed for the genotype combinations p53 PIN3 A1/A1 -p21 31 C/A, in the total study population (OR 0.45), and p53 PIN3 A1/A2-p21 31 C/C, in non-white women (OR 0.28). In Whites, p53 72 C-containing (OR 3.06) and p53 PIN3 A2-containing (OR 6.93) genotypes were associated with SLE risk, and higher OR value was observed for the combined genotype p53 72 G/C-p53 PIN3 A1/A2 (OR 9.00). Further, p53 PIN3 A1/A2 genotype was associated with serositis (OR 2.82), while p53 PIN3 A2/A2 and p53 72 C/C genotypes were associated with neurological disorders (OR 4.69 and OR 3.34, respectively). Conclusions Our findings showed that the TP53 and p21 polymorphisms included in this study may have potential to emerge as SLE susceptibility markers for specific groups of patients. Significant interactions of the TP53 polymorphisms with serositis and neurological disorders were also observed in SLE patients. Highlights The polymorphisms TP53 rs1042522 (G > C) and TP53 rs17878362 (16 bp Del/Ins) were associated with SLE risk in whites. In whites, the combined genotype TP53 rs1042522 GC- TP53 rs17878362 A1A2 and the haplotype TP53 rs1042522 C-rs17878362 A2 represented higher SLE risk. Combination of TP53 rs17878362 (16 bp Del/Ins) and p21 rs1801270 (C > A) protected against SLE in non-white women. TP53 and p21 (CDKN1A) polymorphisms may be SLE susceptibility markers for specific groups.

Roles of CDKN1A gene polymorphisms (rs1801270 and rs1059234) in the development of cervical neoplasia.

The CDKN1A gene product is a p53 downstream effector, which participates in cell differentiation, development process, repair, apoptosis, senescence, migration, and tumorigenesis. The objective of our study was investigated the importance of two polymorphisms in the CDKN1A gene, rs1801270 (31C>A) and rs1059234 (70C>T), for the development of cervical lesions in a Southeastern Brazilian population (283 cases, stratified by lesion severity, and 189 controls). CDKN1A genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and/or DNA sequencing. CDKN1A 31A allele presents a genetic pattern of protection for the development of high-grade cervical lesions (CC vs CA genotype: OR = 0.60; 95 % CI = 0.38-0.95; p = 0.029; CA+AA vs CC genotype: OR = 0.60; 95 % CI = 0.39-0.93; p = 0.021). Allele distributions of the CDKN1A 70C>T polymorphism were also different between the two study groups, with the CDKN1A 70T allele being less prevalent among cases. Moreover, the double heterozygote genotype combination 31CA-70CT decreases the chance of developing high-grade squamous intraepithelial lesion (HSIL) and cancer (OR = 0.55; 95 % CI = 0.32-0.93; p = 0.034) by 50 %, representing a protective factor against the development of more severe cervical lesions.

Novel microduplications at Xp11.22 including HUWE1: clinical and molecular insights into these genomic rearrangements associated with intellectual disability.

Recently, we defined a minimal overlapping region for causal Xp11.22 copy number gains in males with intellectual disability (ID), and identified HECT, UBA and WWE domain-containing protein-1 (HUWE1) as the primary dosage-sensitive gene, whose overexpression leads to ID. In the present study, we used this minimal interval to search for HUWE1 copy number variations by quantitative polymerase chain reaction in a large cohort of Brazilian males with idiopathic ID. We detected two unrelated sporadic individuals with syndromic ID carrying unique overlapping duplications encompassing HUWE1. Breakpoint junction analysis showed a simple tandem duplication in the first patient, which has probably arisen by microhomology-mediated break-induced repair mechanism. In the second patient, the rearrangement is complex having an insertion of an intrachromosomal sequence at its junction. This kind of rearrangement has not been reported in Xp11.22 duplications and might have emerged by a replication- or recombination-based mechanism. Furthermore, the presence of infantile seizures in the second family suggests a potential role of increased KDM5C expression on epilepsy. Our findings highlight the importance of microduplications at Xp11.22 to ID, even in sporadic cases, and reveal new clinical and molecular insight into HUWE1 copy number gains.

Associação entre a homocisteína e os polimorfismos do gene da MTHFR em mulheres brasileiras obesas / Association between homocysteine and polymorphisms in MTHFR in Brazilian obese women

Fundamentos: Pesquisas nacionais brasileiras indicam aumento da obesidade e doenças cardiovasculares em mulheres. Objetivo: Determinar a frequência dos polimorfismos 677C>T e 1298A>C do gene da metilenotetra-hidrofolato redutase (MTHFR) em mulheres brasileiras obesas e avaliar sua associação com as concentrações séricas de homocisteína (Hcy),folato e cobalamina, no período após a fortificação das farinhas de trigo e milho com ácido fólico no Brasil. Métodos: Estudo transversal realizado no período de 2008 a 2009, com 133 mulheres obesas. Kits comerciais foramutilizados para realizar análises laboratoriais, incluindo mensuração de lipídeos e glicose por métodos enzimáticos; Hcy total e o folato plasmático, utilizando um imunoensaio competitivo; e cobalamina baseado em quimiluminescência. A genotipagem foi realizada por PCR, seguido por fragmento de restrição enzimática. Resultados: A média de idade dos participantes foi 39,0±4,4 anos e o índice de massa corporal, 32,5±2,1 kg/m². Distribuições dos genótipos encontradas: CC (47%), CT (44%) e TT (9%) para a posição 677 da MTHFR e AA (60%), AC (35%), e CC (5%) para a posição 1298. As concentrações de Hcy correlacionaram-se negativamente com a concentração de folato plasmático no grupo exibindo os genótipos 677CT, 1298AC ou 1298CC (r=0,554, p<0,01). Conclusão: Mulheres brasileiras obesas com genótipos 677TT estudadas apresentaram maiores concentrações de Hcy do que aquelas que apresentaram os genótipos 677CT e 677CC. Além disso, genótipos 1298CC mostraram associação com concentrações de Hcy maiores do que os genótipos 1298AC e 1298AA.

Background: Brazilian national surveys have indicated a rise in obesity and cardiovascular disease in women.Objective: To determine the frequency of 677C>T and 1298A>C polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene in obese Brazilian women and to assess the potential association of these polymorphisms with serum concentrations of homocysteine (Hcy), folate and cobalamin after fortification of wheat and corn flour with folic acid in Brazil. Methods: A cross-sectional study was conducted from 2008 to 2009 with 133 obese women. Commercial kits were employed to perform laboratory analyses including measurement of lipids and glucose using enzymatic methods, total Hcy and serum folate using a competitive immunoassay and cobalamin based on chemiluminescence. Genotyping was performed by PCR, followed by restriction fragment lengthpolymorphism analysis. Results: The average age of participants was 39.0±4.4 years and mean body mass index was 32.5±2.1kg/m². The distributions of the genotypeswere CC (47%), CT (44%), and TT (9%) for the position MTHFR 677 and AA (60%), AC (35%), and CC (5%) for the position 1298. Hcy levels correlated negatively with serum folate in the group displaying the 677CT, 1298AC, or 1298CC genotypes (r=-0.554, p<0.01). Conclusion: Our findings suggest that obese Brazilian women with genotypes 677TT have higher Hcy concentrations than those carrying the genotypes 677CT and 677CC. Additionally, genotypes 1298CC are associated with higher Hcy concentrations than genotypes 1298AC and 1298AA.

A novel in-frame deletion affecting the BAR domain of OPHN1 in a family with intellectual disability and hippocampal alterations.

Oligophrenin-1 (OPHN1) is one of at least seven genes located on chromosome X that take part in Rho GTPase-dependent signaling pathways involved in X-linked intellectual disability (XLID). Mutations in OPHN1 were primarily described as an exclusive cause of non-syndromic XLID, but the re-evaluation of the affected individuals using brain imaging displayed fronto-temporal atrophy and cerebellar hypoplasia as neuroanatomical marks. In this study, we describe clinical, genetic and neuroimaging data of a three generation Brazilian XLID family co-segregating a novel intragenic deletion in OPHN1. This deletion results in an in-frame loss of exon 7 at transcription level (c.781_891del; r.487_597del), which is predicted to abolish 37 amino acids from the highly conserved N-terminal BAR domain of OPHN1. cDNA expression analysis demonstrated that the mutant OPHN1 transcript is stable and no abnormal splicing was observed. Features shared by the affected males of this family include neonatal hypotonia, strabismus, prominent root of the nose, deep set eyes, hyperactivity and instability/intolerance to frustration. Cranial MRI scans showed large lateral ventricles, vermis hypoplasia and cystic dilatation of the cisterna magna in all affected males. Interestingly, hippocampal alterations that have not been reported in patients with loss-of-function OPHN1 mutations were found in three affected individuals, suggesting an important function for the BAR domain in the hippocampus. This is the first description of an in-frame deletion within the BAR domain of OPHN1 and could provide new insights into the role of this domain in relation to brain and cognitive development or function.

Copy-number gains of HUWE1 due to replication- and recombination-based rearrangements.

We previously reported on nonrecurrent overlapping duplications at Xp11.22 in individuals with nonsyndromic intellectual disability (ID) harboring HSD17B10, HUWE1, and the microRNAs miR-98 and let-7f-2 in the smallest region of overlap. Here, we describe six additional individuals with nonsyndromic ID and overlapping microduplications that segregate in the families. High-resolution mapping of the 12 copy-number gains reduced the minimal duplicated region to the HUWE1 locus only. Consequently, increased mRNA levels were detected for HUWE1, but not HSD17B10. Marker and SNP analysis, together with identification of two de novo events, suggested a paternally derived intrachromosomal duplication event. In four independent families, we report on a polymorphic 70 kb recurrent copy-number gain, which harbors part of HUWE1 (exon 28 to 3' untranslated region), including miR-98 and let-7f-2. Our findings thus demonstrate that HUWE1 is the only remaining dosage-sensitive gene associated with the ID phenotype. Junction and in silico analysis of breakpoint regions demonstrated simple microhomology-mediated rearrangements suggestive of replication-based duplication events. Intriguingly, in a single family, the duplication was generated through nonallelic homologous recombination (NAHR) with the use of HUWE1-flanking imperfect low-copy repeats, which drive this infrequent NAHR event. The recurrent partial HUWE1 copy-number gain was also generated through NAHR, but here, the homologous sequences used were identified as TcMAR-Tigger DNA elements, a template that has not yet been reported for NAHR. In summary, we showed that an increased dosage of HUWE1 causes nonsyndromic ID and demonstrated that the Xp11.22 region is prone to recombination- and replication-based rearrangements.

Exon dosage variations in Brazilian patients with Parkinson's disease: analysis of SNCA, PARKIN, PINK1 and DJ-1 genes.

Parkinson's disease is one of the most common neurodegenerative disorders associated with aging, reaching ∼ 2% of individuals over 65 years. Knowledge achieved in the last decade about the genetic basis of Parkinson's disease clearly shows that genetic factors play an important role in the etiology of this disorder. Exon dosage variations account for a high proportion of Parkinson's disease mutations, mainly for PARKIN gene. In the present study, we screened genomic rearrangements in SNCA, PARKIN, PINK1 and DJ-1 genes in 102 Brazilian Parkinson's disease patients with early onset (age of onset ⩽ 50 years), using the multiplex ligation-dependent probe amplification method. Family history was reported by 24 patients, while 78 were sporadic cases. Screening of exon dosage revealed PARKIN and PINK1 copy number variations, but no dosage alteration was found in SNCA and DJ-1 genes. Most of the carriers harbor heterozygous deletions or duplications in the PARKIN gene and only one patient was found to have a deletion in PINK1 exon 1. Data about dosage changes are scarce in the Brazilian population, which stresses the importance of including exon dosage analysis in Parkinson's disease genetic studies.

Mutational analysis of GIGYF2, ATP13A2 and GBA genes in Brazilian patients with early-onset Parkinson's disease.

In the last decade, several genes have been linked to Parkinson's disease (PD), including GIGYF2, ATP13A2 and GBA. To explore whether mutations in these genes contribute to development of PD in the Brazilian population, we screened 110 patients with early-onset PD. No clearly pathogenic mutations were identified in ATP13A2 and GIGYF2. In contrast, we identified a significantly higher frequency of known pathogenic mutations in GBA gene among the PD cases (6/110=5.4%) when compared to the control group (0/155) (P=0.0047). Our results strongly support an association between GBA gene mutations and an increased risk of PD. Mutations in GIGYF2 and ATP13A2 do not seem to represent a risk factor to the development of PD in the Brazilian population. Considering the scarcity of studies on GIGYF2, ATP13A2 and GBA mutation frequency in Latin American countries, we present significant data about the contribution of these genes to PD susceptibility.

A MECP2 mutation in a highly conserved aminoacid causing mental retardation in a male.

MeCP2 is a protein that functions as a key factor in epigenetic transcriptional regulation. Mutations in MECP2 gene have been reported as being the major cause of Rett syndrome. These mutations may also cause a wide spectrum of neurological disorders in males. Here, we report the identification of the mutation p.P405L in a 19-year-old Brazilian male with mental retardation. This variant is localized in a highly conserved aminoacid from the carboxy terminal domain and may affect the protein function. Segregation analysis on the patient's mother revealed that this is a de novo mutation and it was not identified in the control sample. The programs SIFT, PolyPhen and A-GVGD considered that the p.P405L may be damaging. Despite the high frequency of non pathogenic variants that have been identified in this gene, our data lead us to consider the p.P405L a disease-causing mutation.