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Colorectal cancer (CRC) is the third most common cancer and one of the main causes of death around the world. Multiple lines of evidence have suggested the role of the corticotropin-releasing hormone (CRH) family in CRC induction, including the low expression of corticotropin-releasing hormone receptor 2 ( CRHR2), which is an angiogenesis inhibitor and inflammatory modulator. Previous research suggests that CRHR2 expression in colonic intestinal cells can regulate migration, proliferation and apoptosis through the modulation of several pathways. The aim of this study was to analyze the association of the rs10250835, rs2267716 and rs2267717 variants of CRHR2 gene with CRC in the Mexican population in order to consider its predictive value in CRC. This cross-sectional study included a group of 187 unrelated patients with sporadic CRC and a control group of 191 healthy blood donors. DNA extraction from peripheral blood was carried out using the Miller method. Identification of the rs10250835 variant was performed using PCR-restriction fragment length polymorphism (RFLP) and the rs2267716 and rs2267717 variants using TaqMan allelic discrimination assay. The minor allele homozygous CC of the rs2267716 variant of CRHR2 showed significant difference between CRC and control group (p=0.025), as well as the GCA haplotype (p=0.007), corresponding to the rs10250835, rs2267716 and rs2267717 variants, respectively. Our results suggest that the rs2267716 variant and GCA haplotype of CRHR2 represent a risk factor for CRC development in Mexican patients.

Colorectal cancer (CRC) is a complex disease due to the large number of factors that influence its development, including variants in tumor suppressor genes.To estimate allelic and genotypic frequencies of c.3915GA and c.5371GA variants of the TSC2 gene in a Mexican population with CRC, as well as to analyze their association with the development of CRC.126 peripheral blood samples from patients diagnosed with sporadic CRC and 134 from healthy individuals, regarded as the control group, were included. Identification of genotypes was carried out using traditional PCR and enzymatic digestion. All individuals signed an informed consent letter.The A allele of the c.3915GA variant (OR = 0.31, 95% CI = 0.15-0.69, p = 0.004), as well as A/G haplotype of the c.3915GA and c.5371GA variants (OR = 0.28, 95% CI = 0.12-0.68, p = 0.005) showed a possible protective effect against sporadic CRC. In silico analysis indicated that both variants generate modifications in the splicing process.The presence of TSC2 gene c.3915GA variant suggests a possible protective effect against sporadic CRC in the Mexican population; however, no association was observed with the c.5371GA variant.El cáncer colorrectal (CCR) es una enfermedad compleja debido al gran número de factores que influyen en su desarrollo, incluyendo variantes en genes supresores de tumores.Estimar las frecuencias alélicas y genotípicas de las variantes c.3915GA y c.5371GA del gen TSC2 en una población mexicana con CCR, así como analizar la asociación con el desarrollo de CCR.Se incluyeron 126 muestras de sangre periférica de pacientes con diagnóstico de CCR esporádico y 134 de individuos sanos, considerados como grupo de control. La identificación de los genotipos se llevó a cabo mediante PCR tradicional y digestión enzimática. Todos los individuos firmaron una carta de consentimiento informado.El alelo A de la variante c.3915GA (RM = 0.31, IC 95 % = 0.15-0.69, p = 0.004), así como el haplotipo A/G de las variantes c.3915GA y c.5371GA (RM = 0.28, IC 95 % = 0.12-0.68, p = 0.005) mostraron un posible efecto protector contra CCR esporádico. El análisis in silico indicó que ambas variantes generan modificaciones en el proceso de corte y empalme.La presencia de la variante c.3915GA del gen TSC2 sugiere un posible efecto protector contra CCR esporádico en población mexicana; sin embargo, no se observó esta asociación con la variante c.5371GA.

Aims: The 5HTT gene has been associated with obesity; this study aimed to determine the association between L- and S-alleles at the 5HTTLPR polymorphism with obesity in indigenous Mexican populatio...

Colorectal cancer (CRC) is the third most common cancer and one of the main causes of death around the world. Multiple lines of evidence have suggested the role of the corticotropin-releasing hormone (CRH) family in CRC induction, including the low expression of corticotropin-releasing hormone receptor 2 (

Summary Background Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms have been associated with overweight people and obesity. The goal of this study was to investigate the relationship of the MTHFR 677C>T polymorphism with obesity and biochemical variables in young individuals of Mexico. Methods A total of 316 young individuals were included in the study, 172 with normal weight (NW) and 144 with over weight/obesity. Body mass index (BMI) was classified as NW, overweight, and obesity. Also, waist circumference was measured. Moreover, glucose, total cholesterol, and triglycerides were determined. Genotyping for MTHFR 677C>T polymorphism was performed by the PCR-RFLP method. Results There was no difference in the distribution of the MTHFR 677C>T polymorphism between individuals with NW and overweight/obesity; neither when they were divided by overweight vs NW, nor when we contrasted obese vs NW. However, an analysis stratified by gender showed a significant protector effect of the TT genotype against obesity in males and elevated waist circumference in females. Also, overweight/obese individuals with TT genotype had less risk of high cholesterol or triglycerides than overweight/obese subjects with the other genotypes. Conclusions These results suggest that the MTHFR 677T polymorphism might not be a risk factor for being overweight/obesity. Rather, on the basis of our results, this variant could be a protector effect. However, further large-scale population-based studies are still necessary to clarify the role of the MTHFR 677C>T polymorphism in overweight, obesity, and lipid profile level.

Introduction. Attention deficit hyperactivity disorder (ADHD) is one of the most common neuropsychiatric conditions in childhood and a multifactorial condition attributable to genetic and/or environmental influence. Allelic variants in the serotonin transporter gene ( SLC6A4 ) have been associated to lower transcriptional efficiency, changes in serotonin concentration in several brain regions, and ADHD development. Objective. To identify the association between the SLC6A4 alleles and ADHD diagnosis and risk factor phenotypes in children from a Mexican mestizo population. Method. In this study, 134 unrelated children were included and evaluated for ADHD, genotypification for the 5HTTLPR polymorphism, and identification of multiple phenotypes from their clinical records and family background for association analysis. Results. The following distribution of genotypes was observed: 23% SS, 49% SL, and 28% LL. From the phenotypes evaluated in the present study, gestational diabetes mellitus ( p = .045), history of epilepsy ( p = .047), and parental substance abuse ( p = .033) showed an association with ADHD development in regression analysis along with the S variant. Discussion and conclusion. Results suggest that interaction of the S allele and some of the phenotypes analyzed may play a relevant role in the development of ADHD in the studied population.

There are currently about 415 million people with diabetes worldwide, a figure likely to increase to 642 million by 2040. In 2015, Mexico was the second Latin American country and sixth in the world in prevalence of this disorder with nearly 11.5 million of patients. Type 2 diabetes (T2D) is the main kind of diabetes and its etiology is complex with environmental and genetic factors involved. Indeed, polymorphisms in several genes have been associated with this disease worldwide. To estimate the genetic epidemiology of T2D in Mexican mestizos a systematic bibliographic search of published articles through PubMed, Scopus, Google Scholar, and Web of Science was conducted. Just case-control studies of candidate genes about T2D in Mexican mestizo inhabitants were included. Nineteen studies that met the inclusion criteria were found. In total, 68 polymorphisms of 41 genes were assessed; 26 of them were associated with T2D risk, which were located in ABCA1, ADRB3, CAPN10, CDC123/CAMK1D, CDKAL1, CDKN2A/2B, CRP, ELMO1, FTO, HHEX, IGF2BP2, IRS1, JAZF1, KCNQ1, LOC387761, LTA, NXPH1, SIRT1, SLC30A8, TCF7L2, and TNF-α genes. Overall, 21 of the 41 analyzed genes were associated with T2D in Mexican mestizos. Such a genetic heterogeneity compares with findings in other ethnic groups.

Objetivo: comparar la prevalencia de deterioro cognoscitivo en adultos mayores con y sin diabetes mellitus tipo 2 (dm2) en una unidad de atención primaria. Métodos: estudio transversal realizado en Ciudad Mante, Tamaulipas, México. Se utilizó un muestreo probabilístico aleatorio simple; se realizó el cálculo de muestra para poblaciones finitas con un nivel de confianza de 95%, se evaluaron 153 pacientes. Se tomaron como criterios de inclusión adultos mayores con y sin dm2, sin diagnóstico de deterioro cognitivo, demencia o depresión. Se aplicó la versión modificada del Mini Mental State Examination (mmse) validado en población mexicana, se realizaron análisis de estadística descriptiva e inferencial mediante χ2, un valor pResultados: se evaluaron 153 pacientes, la media de edad fue 69.76 años (±6.82), predominó el sexo femenino con 91 participantes (60%). Todos los pacientes se dividieron en dos grupos, el primero fue en base al diagnóstico de dm2 con 80 participantes (52.3%) y el segundo, sin esta enfermedad con 73 (47.7%); de manera global, 48 pacientes se encontraban con riesgo de deterioro cognitivo, en el grupo con dm2, fue de 13.72% (n=21), mientras que en el grupo sin dm2, fue de 17.64% (n=27). No hubo diferencias estadísticamente significativas en ninguno de los grupos (p > 0,05). Conclusión: no se encontraron diferencias estadísticamente significativas que apoyaran un predominio de deterioro cognoscitivo en pacientes con dm2, aspecto contemplado en otros estudios; se debe ahondar en otras características clínicas y el curso de vida de cada paciente a fin de establecer posibles asociaciones entre las variables de estudio.

Background Adiponectin protein and some variations in its gene, ADIPOQ have recently been associated with cancer because they regulate glucose and lipid metabolism as well as anti-apoptotic and anti-inflammatory proteins. Aim The aim of this study was to analyse the relationship between selected biochemical markers, anthropometric indices and ADIPOQ rs2241766 and rs1501299 SNPs in ductal infiltrating breast cancer (DIBC) in a Mexican population. Methods This cross-sectional study included 64 DIBC patients and 167 healthy women. Polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) analysis was performed to identify the genotypes of the rs2241766 (exon 2) and rs1501299 (intron 2) ADIPOQ polymorphisms. Corporal composition and biochemical markers included body mass index (BMI), waist circumference (WC), hip circumference (HC), waist-hip ratio (WHR), glucose, cholesterol, triglycerides and high- and low-density lipoprotein cholesterol. Results Patients with DIBC had higher serum glucose, WC and WHR than controls. Intergroup differences in allele and genotype frequencies were found for both polymorphisms (P < 0.05). Patients carrying the rs2241766 TT and TG genotypes had higher values of WC, HC and WHR, but only TG carriers had higher levels of glucose. For the SNP rs1501299, carriers of the GG genotype in the DIBC group had higher values of glucose, WC, HC and WHR than the respective control group. Conclusions These results suggest that WC, HC and WHR are better predictors of DIBC than BMI. The ADIPOQ SNP rs2241766 emerges as a protective factor, whereas rs1501299 is a risk factor for DIBC development in a Mexican population.

The purpose of this case–control study was to evaluate the association of XRCC1 Arg194Trp and Arg399Gln polymorphisms with susceptibility to breast cancer (BC) in a Mexican population. We analysed DNA samples from 345 BC patients and 352 control subjects by polymerase chain reaction-restriction fragment length polymorphism. The frequency of the 399Gln allele was 23 % in controls and 29 % in patients [OR 1.38 (1.08–1.76); p = 0.01]; genotypes in controls were 60, 36, and 4 % for Arg/Arg, Arg/Gln, and Gln/Gln, respectively, while in patients they were 53, 36, and 11 % [OR 2.71 (1.44–5.10); p = 0.0015 for the Gln/Gln genotype]. Regarding the Arg194Trp polymorphism, the frequency of Trp allele was 15 % in controls and 16 % in patients [OR 1.09 (0.82–1.46); p = 0.54]; the genotype frequencies in controls were 74, 23, and 3 % for Arg/Arg, Arg/Trp and Trp/Trp, respectively, while in patients these were 73, 23, and 4 % [OR 1.41 (0.64–3.14); p = 0.39 for the Trp/Trp genotype]. Allele frequencies were consistent with Hardy–Weinberg equilibrium (p = 0.20 for Arg194Trp and p = 0.54 for Arg399Gln). Our results indicate that the 399Gln polymorphism is associated with an increased risk of BC. Additionally, we found that some covariates increase the risk of BC in Mexican women; namely, antecedent of abortions [OR 3.69 (2.17–6.27); p < 0.001], not breastfeeding [OR 2.46 (1.45–4.18); p = 0.001], family history of BC [OR 15.9 (5.09–50.23); p < 0.001], other type of family cancer [OR 31.5 (12.5–79.3); p < 0.001], alcoholism [OR 17.7 (5.2–60.42); p < 0.001], type 2 diabetes mellitus [OR 2.28 (1.26–4.10); p = 0.007], and contraceptive use [OR 2.28 (1.26–4.10); p < 0.001].

The calpain-10 gene is expressed primarily in tissues important in glucose metabolism; thus, some of its polymorphisms have been associated with type 2 diabetes. In this study, we examined the association between the calpain-10 single-nucleotide polymorphism (SNP)-43, SNP-19, and SNP-63 and type 2 diabetes in Mexican mestizos. We included 211 patients and 152 non-diabetic subjects. Polymerase chain reaction was used to identify alleles. We compared allele, genotype, haplotype, and diplotype frequencies between both groups and used the chi-square test to calculate the risk. The allele frequency of SNP-43 allele 1 was 70% in controls and 72% in patients; the GG, GA, and AA genotype frequencies were 48.7, 42.8, and 8.5% in controls and 51.2, 41.7, and 7.1% in patients, respectively. For SNP- 19, the prevalence of allele 1 (2R) was 32% in controls and 39% in patients. In controls, homozygosity (2R/2R) was 10.5%, heterozygosity was 42.8%, and 3R/3R was 46.7%; in cases, these values were 13.3, 50.7, and 36.0%, respectively. For SNP-63, the frequency of allele 1 was 87% in controls and 83% in patients; genotype frequencies in controls were 75.7% (CC), 23% (CT), and 1.3% (TT), and were 69.7, 27.5, and 2.8%, respectively for the cases. Genotype distributions were consistent with Hardy-Weinberg equilibrium. No significant intergroup differences for allele, genotype, haplotype, or diplotype frequencies were observed. We found no association between these polymorphisms and diabetes. However, our sample size was small, so the role of calpain-10 risk alleles should be further examined.

The nuclear factor-erythroid 2- (NF-E2-) related factor 2 (Nrf2) is abated and its ability to reduce oxidative stress is impaired in type 2 diabetes and obesity. Thus, the aim of this study was to explore if polymorphisms in Nrf2 and target genes are associated with diabetes and obesity in Mexican mestizo subjects. The rs1800566 ofquinone oxidoreductase 1 (NQO1) gene, rs7211 of thioredoxin interacting protein (TXNIP) gene, rs2071749 of heme oxygenase-1 (HMOX1) gene, and the rs6721961 and the rs2364723 from Nrf2 gene were genotyped in 627 diabetic subjects and 1020 controls. The results showed that the rs7211 polymorphism is a protective factor against obesity in nondiabetic subjects (CC + CT versus TT, OR = 0.40, P = 0.005) and in women (CC versus CT + TT, OR = 0.7, P = 0.016). TT carriers had lower high-density lipoprotein cholesterol levels and lower body mass index. The rs2071749 was positively associated with obesity (AA versus AG + GG, OR = 1.25, P = 0.026). Finally, the rs6721961 was negatively associated with diabetes in men (CC versus CA + AA, OR = 0.62, P = 0.003). AA carriers showed lower glucose concentrations. No association was found for rs1800566 and rs2364723 polymorphisms. In conclusion, the presence of Nrf2 and related genes polymorphisms are associated with diabetes and obesity in Mexican patients.

Acute lymphoblastic leukemia is the major pediatric cancer in developed countries. To date most association studies of acute lymphoblastic leukemia have been based on the candidate gene approach and have evaluated a restricted number of polymorphisms. Such studies have served to highlight difficulties in conducting statistically and methodologically rigorous investigations into acute lymphoblastic leukemia risk. Recent genome-wide association studies of childhood acute lymphoblastic leukemia have provided robust evidence that common variation at four genetic loci confers a modest increase in risk. The accumulated experience to date and relative lack of success of initial efforts to identify novel acute lymphoblastic leukemia predisposition loci emphasize the need for alternative study designs and methods. The International Childhood Acute Lymphoblastic Leukaemia Genetics Consortium includes 12 research groups in Europe, Asia, the Middle East and the Americas engaged in studying the genetics of acute lymphoblastic leukemia. The initial goal of this consortium is to identify and characterize low-penetrance susceptibility variants for acute lymphoblastic leukemia through association-based analyses. Efforts to develop genome-wide association studies of acute lymphoblastic leukemia, in terms of both sample size and single nucleotide polymorphism coverage, and to increase the number of single nucleotide polymorphisms taken forward to large-scale replication should lead to the identification of additional novel risk variants for acute lymphoblastic leukemia. Ethnic differences in the risk of acute lymphoblastic leukemia are well recognized and thus in assessing the interplay between inherited and non-genetic risk factors, analyses using different population cohorts with different incidence rates are likely to be highly informative. Given that the frequency of many acute lymphoblastic leukemia subgroups is small, identifying differential effects will realistically only be possible through multi-center pooled analyses. Here, we review the rationale for identifying genetic risk variants for acute lymphoblastic leukemia and our proposed strategy for establishing the International Childhood Acute Lymphoblastic Leukaemia Genetics Consortium.

As a result of their high prevalence, mayor depressive disorder single episode (MDDSE); major depressive disorder recurrent episodes (MDDREC); and dysthymia are considered an important public health problem. The objective of this paper was to identify and correlate environmental factors in patients with MDDSE, MDDREC and dysthymia.121 patients from the Instituto Mexicano del Seguro Social's Subzone General Hospital of San Andres Tuxtla, at Veracruz, were questioned by history with the risk variables.16 of them were diagnosed with MDDREC, 72 with MDD and 33 with dysthymia; in all of those cases, females prevailed. Depressive disorders were observed more frequently in people over 40 years, married, with medium or low educational level, with dysfunctional family environment, victims of family violence and who were the middle siblings. The main comorbidities that arose were gastrointestinal disorders, obesity and hypertension.16 of them were diagnosed with MDDREC, 72 with MDD and 33 with dysthymia; in all of those cases, females prevailed. Depressive disorders were observed more frequently in people over 40 years, married, with medium or low educational level, with dysfunctional family environment, victims of family violence and who were the middle siblings. The main comorbidities that arose were gastrointestinal disorders, obesity and hypertension.The main risk factors identified for developing depressive disorders were: being female, over 40 years old and being married. The differences obtained in this study, if it is compared with others, are probably due to sample size, selection criteria and ethnic origin.Introducción: debido a su alta prevalencia, la depresión mayor, episodio único (DMEU); la depresión mayor recurrente (DMR); y la distimia son consideradas un problema importante de salud pública. El objetivo de este estudio fue identificar y relacionar los factores ambientales en pacientes con DMEU, DMR y distimia. Métodos: 121 pacientes procedentes del Hospital General de Subzona del Instituto Mexicano del Seguro Social (IMSS) de San Andrés Tuxtla, Veracruz, fueron cuestionados mediante una historia clínica con las variables de riesgo. Resultados: 16 pacientes presentaron DMEU, 72 DMR y 33 distimia. En todos prevaleció el sexo femenino. Los trastornos depresivos se observaron con más frecuencia en personas de más de 40 años, casadas, con un nivel de estudios medio o bajo, provenientes de una familia disfuncional, víctimas de violencia familiar, además de ser hijos intermedios. Las comorbilidades que se presentaron fueron trastornos gastrointestinales, obesidad e hipertensión arterial. Conclusión: los principales factores de riesgo que se identificaron para desarrollar trastornos depresivos fueron: ser mujer, tener más de 40 años de edad y estar casada. Las diferencias obtenidas en este estudio respecto a otros probablemente se deban al tamaño de la muestra, los criterios de selección y el origen de la etnia.

Multiple myeloma (MM) is characterized by abnormal proliferation of clonal plasma cells or monoclonal plasmacytosis, resulting in accumulation of clonal immunoglobulins. Monoclonal gammopathy of unknown significance (MGUS) is considered a premorbid stage for developing MM. Studies have shown an increased risk of MGUS in first-degree relatives of patients with MM. Detection of immunoglobulin heavy chain gene (IGH) rearrangement provides a useful tool for assessing clonality. The aim of this study was to determine clonality in peripheral blood samples from 61 healthy first-degree relatives of MM probands by sorting circulating lymphocytes and detection of the IGH rearrangements in these cells. We detected 16 out of 61 (26.2 %) relatives with monoclonal complete and incomplete IGH rearrangements; only three of them showed elevated monoclonal immunoglobulin in the serum protein electrophoresis. We conclude that this strategy is able to identify efficiently clonality in peripheral blood samples from first-degree relatives of patients with MM, who have a non-negligible risk of developing MGUS or other plasma cell dyscrasias.

The osteochondrodysplasias represent a heterogeneous group of cartilage and bone diseases. Among these, achondrogenesis 1B, atelosteogenesis type II, diastrophic dysplasia, and autosomal recessive multiple epiphyseal dysplasia are caused by mutations in the solute carrier family 26 (sulfate transporter), member 2 gene (SLC26A2). This group of osteochondrodysplasias shows a continuous spectrum of clinical variability and shares many features in common. Usually, it is difficult to distinguish clinically among these patients. To date, several efforts have been made to correlate mutations in the SLC26A2 gene with phenotypic severity in the patients. We report on a Mexican girl with diastrophic dysplasia presenting some unusual clinical and radiographic features that are usually observed in atelosteogenesis type II. Molecular analysis of the SLC26A2 gene in this patient showed compound heterozygosity for the R178X and R279W mutations. In this patient, the combination of a mild and a severe mutation has apparently led to an intermediate or transitional clinical picture, showing an apparent genotype-phenotype correlation.

Introduction Beckwith–Wiedemann syndrome is an overgrowth syndrome that is characterized by hypoglycemia at birth, coarse face, hemihypertrophy and an increased risk to develop embryonal tumors. In approximately 15% of patients, the inheritance is autosomal dominant with variable expressivity and incomplete penetrance, whereas the remainder of Beckwith–Wiedemann syndrome cases are sporadic. Beckwith–Wiedemann syndrome molecular etiologies are complex and involve the two imprinting centers 1 (IC1) and 2 (IC2) of 11p15 region. This case report describes, for the first time, the unusual association of ovotesticular disorder in a patient from Morelia, Mexico with Wiedemann-Beckwith syndrome. Case presentation We report the case of a Mexican six-year-old girl with Beckwith–Wiedemann Syndrome, ambiguous genitalia, and bilateral ovotestes. She has a 46,XX karyotype without evidence of Y-chromosome sequences detected by fluorescence in situ hybridization with both SRY and wcp-Y probes. Conclusion Although a random association between these two conditions cannot be excluded, future analysis of this patient with Beckwith–Wiedemann syndrome and 46,XX ovotesticular disorder may lead to new insights into these complex pathologies. We speculate that a possible misregulation in the imprinted genes network has a fundamental role in the coexistence of these two disorders.

DNA repair proteins maintain DNA integrity; polymorphisms in genes coding for these proteins can increase susceptibility to colorectal cancer (CRC) development. We analyzed a possible association of MLH1 -93GA and 655AG and XRCC1 Arg194Trp and Arg399Gln polymorphisms with CRC in Mexican patients. Genomic DNA samples were obtained from peripheral blood of 108 individuals with CRC (study group) at diagnosis and 120 blood donors (control group) from Western Mexico; both groups were mestizos. The polymorphisms were detected by PCR-RFLP. Association was estimated by calculating the odds ratio (OR). We found that the MLH1 and XRCC1 polymorphisms were in Hardy- Weinberg equilibrium. The MLH1 655AG polymorphism in the 655G allele was associated with a 2-fold increase risk for CRC (OR = 2.04 and 95% confidence interval (95%CI) = 1.12-3.69; P0.01), while the MLH1 -93GA polymorphism allele was associated with a protective effect (OR = 0.60, 95%CI = 0.40-0.89; P = 0.01 in the -93A allele and OR = 0.32, 95%CI = 0.13-0.79; P = 0.01 in the AA genotype). The XRCC1 Arg194Trp and Arg399Gln polymorphisms did not show any significant associations. In conclusion, we found that MLH1 -93GA and 655AG polymorphisms are associated with CRC in Mexican patients.

The serotonergic system has been hypothesized to contribute to the biological susceptibility to type 2 diabetes mellitus (T2DM) and body-mass index (BMI) categories. We investigate a possible association of 5-HTTLPR polymorphism (L and S alleles) in the promoter region of the serotonin transporter gene (SLC6A4) with the development of T2DM and/or higher BMI by analyzing a sample of 138 individuals diagnosed with T2DM and 172 unrelated controls from the Mexican general population. In the total sample genotypes were distributed according to Hardy- Weinberg equilibrium, and S allele frequency was 0.58. There was no statistical association between 5-HTTLPR polymorphism and the development of T2DM in this Mexican population sample (p = 0.12). Nevertheless, logistic regression analysis of the L allele and increased BMI disclosed an association, after adjusting for age, sex and T2DM (p = 0.02, OR 1.74, 95% CI: 1.079-2.808).

Leptin and adiponectin are cytokines produced by adipose tissue with opposite effects on tumor growth: the former stimulate whereas the latter inhibit it. The objective was to analyze the association of LEP A19G and ADIPOQ+45 T/G and +276 G/T polymorphisms in Mexican patients with colorectal cancer (CRC). 68 unrelated patients with CRC (study group) and 102 blood donors (control group); all subjects were Mestizos from western Mexico. The polymorphisms were established by PCR-RFLP on DNA samples obtained from peripheral blood. The LEP A19G polymorphism showed significant differences between CRC patients and control group (p= 0.01 for G/A genotype and p= 0.02 for the recessive model G/G +G/A); yet, in the analysis stratified by gender, this difference remained significant only in males. The ADIPOQ polymorphisms did not shown any significant differences. Our results suggest that the A19G LEP polymorphism is associated with CRC in Mexican patients.

We examined the influence of the Arg194Trp, Arg280His, and Arg399Gln polymorphisms of XRCC1 (X-ray repair cross-complementing group 1) on the development of childhood acute lymphoblastic leukemia (ALL) in 120 ALL patients and 120 controls in Mexico. All of them were genotyped for these polymorphisms, using polymerase chain reaction. No significant differences in allele and genotype frequencies for any polymorphism were observed between patients and controls. Estimation of haplotypes showed the eight expected haplotypes (A-H), seven of which were found in both patients and controls; haplotype A (Arg-Arg-Arg) was the most common, whereas haplotypes F and G were absent in patients and controls, respectively. Haplotype B (Trp-Arg-Arg) was found to be associated with an increased risk of ALL (odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.13-3.37; P = 0.016), particularly in males (OR = 2.65, 95%CI = 1.25-5.63; P = 0.01). Individually, the 194Trp, 280His, and 399Gln alleles were not associated with significantly increased risk for ALL in these Mexican children.

To determine the influence of the MDR1 C3435T polymorphism on the development of childhood acute lymphoblastic leukemia (ALL), we studied 107 children with ALL and 111 healthy subjects. All subjects were genotyped for the C3435T polymorphism using the polymerase chain reaction-restriction fragment length polymorphism method. The genotype frequencies in the patients were 17% homozygous CC, 61% heterozygous CT, and 22% homozygous TT; in healthy individuals the genotype frequencies were 14% CC, 53% CT, and 33% TT. In patients with ALL the allele frequencies were 0.47 for the C allele and 0.53 for the T allele; in the healthy group these allele frequencies were 0.40 and 0.60 for the C and T alleles, respectively. No significant differences in allele frequency (p > 0.176) and genotype frequency (p > 0.255) were detected between the two groups. These findings suggest that the CT or TT genotype does not increase the risk for childhood ALL in Mexican patients. On the other hand, significant differences in allele frequencies were detected in the comparison of Mexican healthy subjects with other populations. Whether these differences are fortuitous or related to diverse genetic backgrounds remains to be elucidated.

Neurogenic diabetes insipidus (NDI) is a rare condition characterized by polyuria and polydipsia caused by deficient arginine vasopressin hormone production. More than a 50 mutations have been identified for familial autosomic dominant neurogenic diabetes insipidus (FadNDI). These mutations can cause citotoxicity and lead to the degeneration of magnocellular neurons of the hipofisis by aberrant protein accumulation. The NDI diagnosis is based on the water deprivation test, quantification of AVP hormone and Magnetic Resonance Image (MRI), and in families with history of FadNDI has been suggested the molecular analysis of mutation in the arginine vasopressin neurophisin II gene before the signs and symptoms development, with the purpose of offering a suitable diagnosis, clinical follow up and treatment. The treatment with a synthetic analogue of AVP hormone allows the remission of the signs and symptoms in NDI patients and the advances in gene therapy in animal models has been promising, as much for NDI as for other diseases in which the mutant protein production has been involved.

The osteochondrodysplasias represent a heterogeneous group of cartilage and bone diseases. Among these, achondrogenesis 1B, atelosteogenesis type II, diastrophic dysplasia, and autosomal recessive multiple epiphyseal dysplasia are caused by mutations in the solute carrier family 26 (sulfate transporter), member 2 gene (SLC26A2). This group of osteochondrodysplasias shows a continuous spectrum of clinical variability and shares many features in common. Usually, it is difficult to distinguish clinically among these patients. To date, several efforts have been made to correlate mutations in the SLC26A2 gene with phenotypic severity in the patients. We report on a Mexican girl with diastrophic dysplasia presenting some unusual clinical and radiographic features that are usually observed in atelosteogenesis type II. Molecular analysis of the SLC26A2 gene in this patient showed compound heterozygosity for the R178X and R279W mutations. In this patient, the combination of a mild and a severe mutation has apparently led to an intermediate or transitional clinical picture, showing an apparent genotype-phenotype correlation.