Whole-Genome Sequencing Reveals a Novel Pathogenic GRIN2B Variant in a Patient with Neurodevelopmental Disorder and an inv(6)(p24p11.2)pat.

INTRODUCTION: Neurodevelopmental disorders (NDDs) are diverse and can be explained by either genomic aberrations or single nucleotide variants. Most likely due to methodological approaches and/or disadvantages, the concurrence of both genetic events in a single patient has hardly been reported and even more rarely the pathogenic variant has been regarded as the cause of the phenotype when a chromosomal alteration is initially identified. CASE PRESENTATION: Here, we describe a NDD patient with a 6p nonpathogenic paracentric inversion paternally transmitted and a de novo pathogenic variant in the GRIN2B gene. Molecular-cytogenetic studies characterized the familial 6p inversion and revealed a paternal 9q inversion not transmitted to the patient. Subsequent whole-genome sequencing in the patient-father dyad corroborated the previous findings, discarded inversions-related cryptic genomic rearrangements as causative of the patient's phenotype, and unveiled a novel heterozygous GRIN2B variant (p.(Ser570Pro)) only in the proband. In addition, Sanger sequencing ruled out such a variant in her mother and thereby confirmed its de novo origin. Due to predicted disturbances in the local secondary structure, this variant may alter the ion channel function of the M1 transmembrane domain. Other pathogenic variants in GRIN2B have been related to the autosomal dominant neurodevelopmental disorder MRD6 (intellectual developmental disorder, autosomal dominant 6, with or without seizures), which presents with a high variability ranging from mild intellectual disability (ID) without seizures to a more severe encephalopathy. In comparison, our patient's clinical manifestations include, among others, mild ID and brain anomalies previously documented in subjects with MRD6. CONCLUSION: Occasionally, gross chromosomal abnormalities can be coincidental findings rather than a prime cause of a clinical phenotype (even though they appear to be the causal agent). In brief, this case underscores the importance of comprehensive genomic analysis in unraveling the wide-ranging genetic causes of NDDs and may bring new insights into the MRD6 variability.

Circulating cell-free-DNA concentration is a good biomarker for diagnosis of colorectal cancer in Mexican patients.

Colorectal cancer (CRC) is the third most common cancer in the world. Overall survival is related to clinical stage: more advanced stages show lower survival rates; therefore, they need to be monitored regularly with new, less invasive and more specific biomarkers. The concentration and integrity index of circulating cell-free DNA (ccfDNA) have been proposed as potential diagnostic and prognostic biomarkers for CRC, however, inconsistent results are still observed in different reports. Here we analyze these potential CRC biomarkers in a Mexican population. In this study, 124 patients with sporadic CRC and 37 healthy individuals were examined as a reference group. The ccfDNA was isolated from plasma samples of all included subjects. The ccfDNA concentration was determined by fluorometry and the integrity index (ALU247/ALU115 ratio) by quantitative PCR amplification (qPCR) of ALU sequences. The results show that ccfDNA concentration was higher in CRC patients than in the reference group (P=0.001). The integrity index showed no significant differences between these groups (P=0.258), except for histological type (P=0.012). A higher ccfDNA concentration was also associated with patients younger than 50 years (P=0.030). The ccfDNA concentration showed significant discriminatory power (AUC: 0.854, C.I.: 0.78-0.92, P=0.001) between patients and the reference group and between tumor-node-metastasis (TNM) stages. In conclusion, ccfDNA concentration proves to be a good diagnostic biomarker for CRC patients, whereas the integrity index did not show diagnostic utility.

RECK Variants are Associated with Clinicopathological Features and Decreased Susceptibility in Mexican Patients with Colorectal Cancer.

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of death worldwide. Down-regulation of the cysteine-rich reversion-inducing protein with Kazal motifs (RECK) has been confirmed in numerous human cancers and is clinically associated with metastasis. This study aims to explore, for the first time, the possible association of the RECK variants rs11788747 and rs10972727 with CRC susceptibility and clinicopathological features. DNA from 130 CRC patients and 130 healthy blood donors was analyzed. Identification of genetic variants was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated using the odds ratio (OR) test and P values were adjusted using the Bonferroni test. Individuals carrying the G/G genotype for the rs11788747 variant showed a lower risk of colorectal cancer (OR 0.33; 95% CI 0.16-0.70; P = 0.006). Patients older than 50 years who carry the G/G genotype have a lower risk of CRC (OR 0.26; 95% CI 0.09-0.73; P = 0.019) and of developing advanced tumor-nodule-metastasis (TNM) stages (OR 0.23; 95% CI 0.09-0.54; P = 0.001). Individuals carrying the A/A genotype of the rs10972727 variant also showed decreased risk of CRC (OR 0.38; 95% CI 0.19-0.77; P = 0.011), and were associated with age (over 50 years), sex, advanced TNM stages, and tumor location in the colon. Our results suggest that the RECK variants studied here (rs11788747 and rs10972727) are associated with decreased CRC risk, TNM stages and tumor location.

CD44 Genotypes Are Associated with Susceptibility and Tumor Characteristics in Colorectal Cancer Patients.

Colorectal cancer is the third cause of cancer and the second leading cause of death worldwide. The CD44 gene plays a key role in malignant processes, including growth, survival, epithelial to mesenchymal transition and metastasis. It is also known that some variants as rs187116 (c.67+4883G>A) and rs7116432 (c.2024+779A>G) can modulate the function of the CD44 gene and malignant transformation in several neoplasms. This study aims to explore, for the first time, the association of the CD44 rs187116 and rs7116432 variants in patients with colorectal cancer. Genomic DNA from 250 patients and 250 healthy blood donors were analyzed. The identification of variants was made by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated by the odds ratio (OR) test and multivariate analysis. Individuals carrying the G/A and A/A genotypes for the rs187116 polymorphism showed an increased risk for colorectal cancer (OR = 3.11, 95% CI: 1.87-5.16, P = 0.001 and OR = 3.59, 95% CI: 2.06-6.25, P = 0.001, respectively). After adjusting for age and gender, these same genotypes and the G/G genotype of the rs7116432 polymorphism were associated with TNM stage and tumor location in the colon. Moreover, the A-G (rs187116 and rs7116432) haplotype was associated with increased risk; while, the haplotype G-A (rs187116 and rs7116432) was related with decreased risk. In conclusion, our results suggest that the here analyzed CD44 variants are involved with risk, TNM stage and tumor location in colorectal cancer.

Genetic Polymorphisms in APC, DVL2, and AXIN1 Are Associated with Susceptibility, Advanced TNM Stage or Tumor Location in Colorectal Cancer.

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of death worldwide. The named "destruction complex" has a critical function in the Wnt/ß-catenin pathway regulating the level of ß-catenin in the cytoplasm and nucleus. Alterations in this complex lead to the cellular accumulation of ß-catenin, which participates in the development and progression of CRC. This study aims to determine the contribution of polymorphisms in the genes of the ß-catenin destruction complex to develop CRC, specifically adenomatous polyposis coli (APC) (rs11954856 G>T and rs459552 A>T), axis inhibition protein 1 (AXIN1) (rs9921222 C>T and rs1805105 C>T), AXIN2 (rs7224837 A>G), and dishevelled 2 (DVL2) (2074222 G>A and rs222836 C>T). Genomic DNA from 180 sporadic colorectal cancer patients and 150 healthy blood donors were analyzed. The identification of polymorphisms was made by polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated by the odds ratio (OR) test. Increased susceptibility to CRC was associated with the polymorphic variants rs11954856 (APC), rs222836 (DVL2), and rs9921222 (AXIN1). Decreased susceptibility was associated with the polymorphisms rs459552 (APC) and 2074222 (DVL2). Association was also observed with advanced Tumor-Node-Metastasis (TNM) stages and tumor location. The haplotypes G-T in APC (rs11954856-rs459552) and A-C in DVL2 (rs2074222-rs222836) were associated with decreased risk of CRC, while the G-T haplotype in the DVL2 gene was associated with increased CRC risk. In conclusion, our results suggest that variants in the destruction complex genes may be involved in the promotion or prevention of colorectal cancer.

Detection of monoclonal B cells in general population from two different regions of Mexico.

To estimate the frequency of monoclonal B cells in Mexican general population from two different regions of Mexico. Monoclonal B cells were detected by rearrangements of the immunoglobulin heavy chains (IGH) in 288 individuals: 188 from a metropolitan area and 100 from a rural area. After DNA extraction from peripheral blood by the CTAB/DTAB method, multiplex PCR was used to amplify the IGH rearrangements, followed by capillary electrophoresis. In together, 9.4% of the studied individuals showed monoclonal B cells. This prevalence is significantly higher to those previously described for other populations, but similar to a report in the Spanish population. Among people from the metropolitan area, 12.8% exhibited monoclonal B cells in comparison with 3% of people from the rural area. All individuals showing monoclonal B cells were elder than 40 years. Higher frequency of incomplete monoclonal rearrangements was observed. Individuals from urban areas show significantly increased frequencies of monoclonal B cells regarding the people from the rural area. It is reasonable to believe that the environmental factor could have a greater impact on the development of monoclonality than the genetic component.

Gene expression profiling demonstrates WNT/ß-catenin pathway genes alteration in Mexican patients with colorectal cancer and diabetes mellitus.

PURPOSE: Several studies have shown a strong association between diabetes mellitus (DM) and increased risk of colorectal cancer (CRC). The fundamental mechanisms that support this association are not entirely understood; however, it is believed that hyperinsulinemia and hyperglycemia may be involved. Some proposed mechanisms include upregulation of mitogenic signaling pathways like MAPK, PI3K, mTOR, and WNT, which are involved in cell proliferation, growth, and cancer cell survival. The purpose of this study was to evaluate the gene expression profile and identify differently expressed genes involved in mitogenic pathways in CRC patients with and without DM. METHODS: In this study, microarray analysis of gene expression followed by quantitative PCR (qPCR) was performed in cancer tissue from CRC patients with and without DM to identify the gene expression profiles and validate the differently expressed genes. RESULTS: Among the study groups, some differently expressed genes were identified. However, when bioinformatics clustering tools were used, a significant modulation of genes involved in the WNT pathway was evident. Therefore, we focused on genes participating in this pathway, such as WNT3A, LRP6, TCF7L2, and FRA-1. Validation of the expression levels of those genes by qPCR showed that CRC patients without type 2 diabetes mellitus (T2DM) expressed significantly more WNT3Ay LRP6, but less TCF7L2 and FRA-1 compared to controls, while in CRC patients with DM the expression levels of WNT3A, LRP6, TCF7L2, and FRA-1 were significantly higher compared to controls. CONCLUSIONS: Our results suggest that WNT/ß-catenin pathway is upregulated in patients with CRC and DM, demonstrating its importance and involvement in both pathologies.

A de novo t(10;19)(q22.3;q13.33) leads to ZMIZ1/PRR12 reciprocal fusion transcripts in a girl with intellectual disability and neuropsychiatric alterations.

We report a girl with intellectual disability (ID), neuropsychiatric alterations, and a de novo balanced t(10;19)(q22.3;q13.33) translocation. After chromosome sorting, fine mapping of breakpoints by array painting disclosed disruptions of the zinc finger, MIZ-type containing 1 (ZMIZ1) (on chr10) and proline-rich 12 (PRR12) (on chr19) genes. cDNA analyses revealed that the translocation resulted in gene fusions. The resulting hybrid transcripts predict mRNA decay or, if translated, formation of truncated proteins, both due to frameshifts that introduced premature stop codons. Though other molecular mechanisms may be operating, these results suggest that haploinsufficiency of one or both genes accounts for the patient's phenotype. ZMIZ1 is highly expressed in the brain, and its protein product appears to interact with neuron-specific chromatin remodeling complex (nBAF) and activator protein 1 (AP-1) complexes which play a role regulating the activity of genes essential for normal synapse and dendrite growth/behavior. Strikingly, the patient's phenotype overlaps with phenotypes caused by mutations in SMARCA4 (BRG1), an nBAF subunit presumably interacting with ZMIZ1 in brain cells as suggested by our results of coimmunoprecipitation in the mouse brain. PRR12 is also expressed in the brain, and its protein product possesses domains and residues thought to be related in formation of large protein complexes and chromatin remodeling. Our observation from E15 mouse brain cells that a Prr12 isoform was confined to nucleus suggests a role as a transcription nuclear cofactor likely involved in neuronal development. Moreover, a pilot transcriptome analysis from t(10;19) lymphoblastoid cell line suggests dysregulation of genes linked to neurodevelopment processes/neuronal communication (e.g., NRCAM) most likely induced by altered PRR12. This case represents the first constitutional balanced translocation disrupting and fusing both genes and provides clues for the potential function and effects of these in the central nervous system.

NME1 and DCC variants are associated with susceptibility and tumor characteristics in Mexican patients with colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) ranks third in cancer incidence globally and is the second leading cause of cancer-related mortality. The nucleoside diphosphate kinase 1 (NME1) and netrin 1 receptor (DCC) genes have been associated with resistance against tumorigenesis and tumor metastasis. This study investigates the potential association between NME1 (rs34214448 G > T and rs2302254 C > T) and DCC (rs2229080 G > C and rs714 A > G) variants and susceptibility to colorectal cancer development. METHODS: Samples from 232 colorectal cancer patients and 232 healthy blood donors underwent analysis. Variants were identified using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Associations were assessed using odds ratios (OR), and the p values were adjusted with Bonferroni test. RESULTS: Individuals carrying the G/T and T/T genotypes for the NME1 rs34214448 variant exhibited a higher susceptibility for develop colorectal cancer (OR = 2.68, 95% CI: 1.76-4.09, P = 0.001 and OR = 2.47, 95% CI: 1.37-4.47, P = 0.001, respectively). These genotypes showed significant associations in patients over 50 years (OR = 2.87, 95% CI: 1.81-4.54, P = 0.001 and OR = 2.99, 95% CI: 1.54-5.79, P = 0.001 respectively) and with early Tumor-Nodule-Metastasis (TNM) stage (P = 0.001), and tumor location in the rectum (P = 0.001). Furthermore, the DCC rs2229080 variant revealed that carriers of the G/C genotype had an increased risk for develop colorectal cancer (OR = 2.00, 95% CI: 1.28-3.11, P = 0.002) and were associated with age over 50 years, sex, and advanced TNM stages (P = 0.001). CONCLUSIONS: These findings suggest that the NME1 rs34214448 and DCC rs2229080 variants play a significant role in colorectal cancer development.

[Ataxia telangiectasia. Diagnosis and follow-up in 4 cases]. / Ataxia telangiectasia. Diagnóstico y seguimiento en una serie de cuatro casos.

Ataxia telangiectasia (AT) is a chromosomal instability syndrome with autosomal recessive inheritance, it is caused by more than 500 mutations of the ATM gene, which is involved in the cellular response to DNA damage. The diagnosis becomes difficult due to the evolution of the disease, their poor knowledge, and limited access to diagnostic tests. Chromosomal damage induced by ionizing radiation (IR) assay is still a sensitive method for early diagnosis, and it is essential for better management and genetic counseling. This paper shows diagnosis and follow-up in four cases with AT.

Functional Variants in MicroRNAs (rs895819, rs11614913 and rs2910164) Are Associated with Susceptibility and Clinicopathological Features in Mexican Patients with Colorectal Cancer.

BACKGROUND: miRNAs are non-coding RNAs participating actively in the post-translational regulation of oncogenes, tumor suppressor, and DNA repair genes implicated in colorectal cancer (CRC). This study aims to examine the association of the variants miR-27a (rs895819 A>G), miR-196a2 (rs11614913 T>G) and miR-146a (rs2910164 C>G) in Mexican CRC patients. METHODS: DNA samples from 183 patients and 186 healthy Mexican subjects were analyzed. Variants were identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated by the odds ratio (OR) and adjusted by the Bonferroni test. RESULTS: Patients carrying the G/G genotype of the rs895819 variant in the miR-27a gene showed an increased risk of CRC (19% vs 12%, P=0.013). A similar tendency was noticed for patients younger than 50 years carrying A/G (48% vs 41%, P=0.014). The A/G genotype in TNM stages I+II (55.7% vs 40.8%, P=0.011) and tumor location in the colon (69.5 vs 40.8%, P=0.001) were also increased. For the variant rs11614913 of the miR-196a2 gene, carriers of the C/C genotype showed an increased risk of CRC (32% vs 22%, P=0.009). This genotype was more frequent in TNM stage III+IV (36.8% vs 22.5%, P=0.007) and the tumor had a more recurrent location in the rectum (31.6% vs 22.5%, P=0.013). The rs2910164 variant of the miR-146a gene was found to have no significant risk associations. CONCLUSION: Our results reveal that the rs895819 variant in miR-27a and rs11614913 in miR-196a2 have a substantial impact on the development of CRC.

Peripheral T-lymphocytes express WNT7A and its restoration in leukemia-derived lymphoblasts inhibits cell proliferation.

BACKGROUND: WNT7a, a member of the Wnt ligand family implicated in several developmental processes, has also been reported to be dysregulated in some types of tumors; however, its function and implication in oncogenesis is poorly understood. Moreover, the expression of this gene and the role that it plays in the biology of blood cells remains unclear. In addition to determining the expression of the WNT7A gene in blood cells, in leukemia-derived cell lines, and in samples of patients with leukemia, the aim of this study was to seek the effect of this gene in proliferation. METHODS: We analyzed peripheral blood mononuclear cells, sorted CD3 and CD19 cells, four leukemia-derived cell lines, and blood samples from 14 patients with Acute lymphoblastic leukemia (ALL), and 19 clinically healthy subjects. Reverse transcription followed by quantitative Real-time Polymerase chain reaction (qRT-PCR) analysis were performed to determine relative WNT7A expression. Restoration of WNT7a was done employing a lentiviral system and by using a recombinant human protein. Cell proliferation was measured by addition of WST-1 to cell cultures. RESULTS: WNT7a is mainly produced by CD3 T-lymphocytes, its expression decreases upon activation, and it is severely reduced in leukemia-derived cell lines, as well as in the blood samples of patients with ALL when compared with healthy controls (p ≤0.001). By restoring WNT7A expression in leukemia-derived cells, we were able to demonstrate that WNT7a inhibits cell growth. A similar effect was observed when a recombinant human WNT7a protein was used. Interestingly, restoration of WNT7A expression in Jurkat cells did not activate the canonical Wnt/ß-catenin pathway. CONCLUSIONS: To our knowledge, this is the first report evidencing quantitatively decreased WNT7A levels in leukemia-derived cells and that WNT7A restoration in T-lymphocytes inhibits cell proliferation. In addition, our results also support the possible function of WNT7A as a tumor suppressor gene as well as a therapeutic tool.

Clinical and molecular characterization of Costello syndrome in unrelated Mexican patients.

This study intends to describe for the first time a cohort of Mexican patients with Costello syndrome. The five exons of the HRAS gene were amplified in DNA samples from 13 patients with a clinical suspicion of Costello syndrome. PCR products were sequenced using the Ready Reaction Big Dye Terminator v.3.0 Kit and an ABI PRISM 310 sequencer. Only five patients (38%) showed causal variant in codon 12 of the HRAS gene (four with the p.Gly12Ser and one with the p.Gly12Ala variant). Three patients showed silent polymorphic variants (p.His27His and p.Leu159Leu). Clinical features in patients carrying the causal variant were variable. The alternative diagnosis of cardio-facio-cutaneous syndrome was considered in patients who did not have a causative variant in HRAS.

MHC class I-related chain A and B ligands are differentially expressed in human cervical cancer cell lines.

BACKGROUND: Natural killer (NK) cells are an important resource of the innate immune system directly involved in the spontaneous recognition and lysis of virus-infected and tumor cells. An exquisite balance of inhibitory and activating receptors tightly controls the NK cell activity. At present, one of the best-characterized activating receptors is NKG2D, which promotes the NK-mediated lysis of target cells by binding to a family of cell surface ligands encoded by the MHC class I chain-related (MIC) genes, among others. The goal of this study was to describe the expression pattern of MICA and MICB at the molecular and cellular levels in human cervical cancer cell lines infected or not with human papillomavirus, as well as in a non-tumorigenic keratinocyte cell line. RESULTS: Here we show that MICA and MICB exhibit differential expression patterns among HPV-infected (SiHa and HeLa) and non-infected cell lines (C33-A, a tumor cell line, and HaCaT, an immortalized keratinocyte cell line). Cell surface expression of MICA was higher than cell surface expression of MICB in the HPV-positive cell lines; in contrast, HPV-negative cells expressed lower levels of MICA. Interestingly, the MICA levels observed in C33-A cells were overcome by significantly higher MICB expression. Also, all cell lines released higher amounts of soluble MICB than of soluble MICA into the cell culture supernatant, although this was most pronounced in C33-A cells. Additionally, Real-Time PCR analysis demonstrated that MICA was strongly upregulated after genotoxic stress. CONCLUSIONS: This study provides evidence that even when MICA and MICB share a high degree of homology at both genomic and protein levels, differential regulation of their expression and cell surface appearance might be occurring in cervical cancer-derived cells.

MKK4 variants rs3826392 and rs3809728 are associated with susceptibility and clinicopathological features in colorectal cancer patients.

OBJECTIVES: The mitogen-activated protein kinase kinase 4 (MKK4) plays a key role in several processes like inflammation, apoptosis, and tumorigenesis. Several authors have proposed that genetic variations in these genes may alter their expression with subsequent cancer risk. This study aimed to examine the possible association of MKK4 rs3826392 and rs3809728 variants in Mexican patients with colorectal cancer (CRC). These variants were also compared with clinical features as sex, age, TNM stage, and tumor location. MATERIALS AND METHODS: The study included genomic DNA from 218 control subjects and 250 patients. Genotyping of the MKK4 variants was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) procedure. RESULTS: Individuals with A/T and T/T genotypes for the rs3809728 (-1044 A>T) variant showed a significantly increased risk for CRC (P=0.012 and 0.007, respectively); while individuals with the G/G genotype for the rs3826392 (-1304 T>G) variant showed a decreased risk for CRC (P=0.012). Genotypes of the MKK4 rs3809728 variant were also significantly related to colon localization and advanced TNM stage in CRC patients. T-T haplotype (rs3826392 and rs3809728) of the MKK4 gene was associated with risk in patients with CRC. CONCLUSION: The rs3826392 variant in the MKK4 gene could be a cancer protective factor, while the rs3809728 variant could be a risk factor. These variants play a significant role in CRC risk.

GSK3ß Polymorphisms Are Associated with Tumor Site and TNM Stage in Colorectal Cancer.

BACKGROUND: Mutations and polymorphisms of the GSK3ß gene have been associated with several diseases including Alzheimer disease, diabetes and cancer; however, to date, no variants of this gene have been associated with colorectal cancer (CRC). This study aims to explore, for the first time, the association of the GSK3ß rs334558 and rs6438552 polymorphisms with CRC. METHODS: Genomic DNA from 330 CRC patients and healthy blood donors were analyzed. Identification of polymorphisms was made by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated by the odds ratio (OR) test. RESULTS: Patients carrying the C/T genotype for the rs334558 (T>C) polymorphism showed an increased risk for CRC (OR = 1.71, 95% CI: 1.05-2.79, P = 0.039); this association was also observed for TNM stage and tumor location. For the rs6438552 (T>C) polymorphism, the OR analysis showed that patients carrying C/T and C/C genotypes have a decreased risk for CRC (OR = 0.44, 95% CI: 0.27-0.70, P = 0.001 and OR = 0.24, 95% CI: 0.10-0.64, P = 0.001, respectively); this decreased risk was also evident in the stratified analysis by TNM stage and tumor location. Haplotype analysis of these 2 loci of GSK3ß (rs334558 and rs6438552) showed differential distribution. The T-T and C-C haplotype was associated with a decreased risk of CRC, while the T-C haplotype was associated with an increased risk of CRC. CONCLUSION: Our results denote that GSK3ß gene polymorphisms play a significant role in promoting or preventing CRC. Additionally, variations in this gene are associated with the tumor site and the tumor-node-metastasis (TNM) stage in these patients.

Micronutrient content and antioxidant enzyme activities in human breast milk.

Breast milk contains micronutrients that function as cofactors of antioxidant enzymes. High concentrations of iron (Fe) and copper (Cu) can increase the production of reactive oxygen species (ROS). This study aimed to assess the relationship between the activity of antioxidant enzymes (superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST)) and the concentration of the micronutrients Fe, Cu and zinc (Zn) in breast milk. Breast milk samples were collected from 108 mothers (7-10 days postpartum, transitional milk). The samples were grouped into three groups according to the number of pregnancies (one, two and three or more pregnancies), also grouped according to the body mass index (BMI) suggested by the World Health Organization (WHO) in underweight, normal weight, overweight and obese. Breast milk Fe, Cu and Zn concentrations were determined by atomic absorption spectrophotometry and the activity of the antioxidant enzymes was determined by spectrophotometry. An increase in GPx, SOD and GST activities in relation to the number of pregnancies was found (p = 0.05, p = 0.04 and p < 0.01, respectively). An inverse relationship between GST activity and BMI was found (p = 0.05). A positive correlation was observed between Cu and Zn concentrations (r = 0.52, p < 0.05). A negative correlation was found between Cu concentration and catalase activity (r = -0.22, p < 0.05); Fe content was negatively correlated with GPx and GST activities (r = -0.32, r = -0.22, respectively, p < 0.05). The activities of antioxidant enzymes (GPx, SOD and GST) may be affected by the number of pregnancies and contribute to prevent oxidation of nutritional molecules in breast milk.

Williams-Beuren syndrome in Mexican patients confirmed by FISH and assessed by aCGH.

Williams-Beuren syndrome (WBS) has a prevalence of 1/7500-20000 live births and results principally from a de novo deletion in 7q11.23 with a length of 1.5 Mb or 1.8 Mb. This study aimed to determine the frequency of 7q11.23 deletion, size of the segment lost, and involved genes in 47 patients with a clinical diagnosis of WBS and analysed by fluorescence in situ hybridization (FISH); among them, 31 had the expected deletion. Micro-array comparative genomic hybridization (aCGH) confirmed the loss in all 18 positive-patients tested: 14 patients had a 1.5 Mb deletion with the same breakpoints at 7q11.23 (hg19: 72726578-74139390) and comprising 24 coding genes from TRIM50 to GTF2I. Four patients showed an atypical deletion: two had a 1.6 Mb loss encompassing 27 coding genes, from NSUN5 to GTF2IRD2; another had a 1.7 Mb deletion involving 27 coding genes, from POM121 to GTF2I; the remaining patient presented a deletion of 1.2 Mb that included 21 coding genes from POM121 to LIMK1. aCGH confirmed the lack of deletion in 5/16 negative-patients by FISH. All 47 patients had the characteristic facial phenotype of WBS and 45 of 47 had the typical behavioural and developmental abnormalities. Our observations further confirm that patients with a classical deletion present a typical WBS phenotype, whereas those with a high (criteria of the American Association of Pediatrics, APP) clinical score but lacking the expected deletion may harbour an ELN point mutation. Overall, the concomitant CNVs appeared to be incidental findings.

Clinical and genetic heterogeneity in patients with mosaic variegated aneuploidy: delineation of clinical subtypes.

Mosaic variegated aneuploidy (MVA) is a rare autosomal recessive syndrome related to BUB1B gene mutations and characterized by multiple mosaic aneuploidies, cancer predisposition, and a distinct phenotype. We report on two mildly affected sibs with MVA syndrome but without BUB1B mutation. Both patients exhibited growth retardation, frontal bossing, triangular face and micrognathia but not microcephaly or cancer. Aneuploidies were assessed both in G-banded metaphases from lymphocyte cultures and in interphase nuclei from buccal cells by FISH. Screening of 23 exons and intron-exon boundaries of BUB1B was also carried out. These patients were then compared with other 19 MVA patients screened for BUB1B mutations. Around one half of the cultured lymphocytes from our patients had aneuploidies ranging from nullisomies to heptasomies; the most frequent abnormalities were trisomies (42%) and monosomies (28%). FISH results demonstrated more chromosomal losses than gains. Screening of BUB1B in our two patients failed to identify any mutation. A review of the 21/35 patients screened for BUB1B demonstrated three clinical pictures. Patients with monoallelic BUB1B mutations were severely affected with Dandy-Walker complex (7/8), cataracts (6/6), and Wilms' tumor (7/8); premature chromatid separation (PCS) was observed in 8/8 propositi and 7/7 carrier parents. Patients without BUB1B mutations were mildly affected with no evidence of cancer, Dandy-Walker malformation or cataract, and rarely (1/7) showed PCS. Finally, patients with biallelic BUB1B mutations showed a moderate phenotype. The distinct MVA clinical groups delineated here point to involvement of at least another mitotic spindle checkpoint gene in addition to the BUB1B gene.

Genetic variation of the FMR1 gene among four Mexican populations: Mestizo, Huichol, Purepecha, and Tarahumara.

Fragile X syndrome is the most common cause of inherited mental retardation; it is caused by expansion of CGG repeats in the first exon of the FMR1 gene. The number of CGG repeats varies between 6 and 50 triplets in normal individuals; the most common alleles have 29 or 30 repeats. Allelic patterns in the global populations are similar; however; some reports show statistical differences among several populations. In Mexico, except by a single report on a western Mestizo population, the allelic frequencies of the FMR1 gene are unknown. In this study, we analyze 207, 140, 138, and 40 chromosomes from Mestizos, Tarahumaras, Huichols, and Purepechas respectively. After PCR amplification on DNA modified by sodium bisulfite treatment, molecular analysis of the FMR1 gene showed 30 different alleles among the 525 chromosomes evaluated. Trinucleotide repeat number in the different Mexican populations varied from 15 to 87, with modal numbers of 32 and 30 in Mestizos and Tarahumaras, 29 and 32 in Purepechas and 30 among Huichols. Together, these allelic patterns differ significantly from those reported for Caucasian, Chinese, African, Indonesian, Brazilian, and Chilean populations. The increased number of the unusual allele of 32 repeats observed in the Mexican mestizo population can be explained from its frequency in at least two Mexican native populations.