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.

Aim: To determine the prevalence of chromosomal abnormalities in couples with reproductive disorders. Methods: A retrospective study was performed in 939 Mexican couples with reproductive disorders (542 with recurrent fetal loss, 356 with malformed/stillborn children, and 41 with sterility) whose karyotype was established on GTG-banded metaphases. Results: A chromosomal aberration was detected in one partner of 52 couples, including a double translocation carrier; therefore, the prevalence of chromosomally abnormal couples was 5.5%; 31 couples with recurrent fetal loss (31/542, 5.7%), 15 with malformed/stillborn children (15/356, 4.2%), and 6 with sterility (6/41, 14.6%). There were 43 couples with structural rearrangements (29 reciprocal translocations, 10 robertsonian translocations, 2 inversions, 1 insertion, and 1 ring) and 9 with gonosomal aneuploidies. The affected partner was female in 28 (53.8%) and male in 24 (46.2%) couples. In addition, 17 couples (1.8%) with the structural variant inversion 9qh were detected. Conclusion: The prevalence of chromosomal abnormalities found in our sample is consistent with figures described in several populations around the world.

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.

In order to assess the frequency of chromosomal abnormalities in azoospermic males from western Mexico, we carried out a retrospective study in 227 patients. Forty-three (18.9%) cases with an abnormal karyotype were found. The most frequent chromosomal anomaly was 47,XXY, which was identified in 35 subjects (15.4%). In six cases (2.6%), structural aberrations were detected: two Robertsonian translocations [(45,XY,t(13;22)(p11;p11) and (45,XY,t(13;15)(p11;p11)], a Y;autosome translocation [46,XY,der(15)t(Y;15)(q12;p11)], and three mosaics [mos45,X/46,X,idic(Y)(q11)]. In general, these findings are in accordance with those from other surveys and confirm that the XXY aneuploidy is the most frequent chromosomal abnormality in azoospermic individuals.

Colorectal cancer (CRC) is one of the most common cancers worldwide. Its etiopathogenesis is complex, mainly influenced by genetic instability caused by the accumulation of mutations. The XRCC1 gene, which is involved in DNA repair, has been associated with CRC through the R194W (C194T) and R399Q (G399A) polymorphisms, but the results are inconsistent. Here, we analyzed the association of these polymorphisms with sporadic CRC in a northeastern Mexican population, including 155 male CRC patients and 155 male controls. Genotyping was performed using the RFLP method. An association with CRC was found for the 399A allele (G vs A; OR = 1.48 (1.03–2.13), ) and for the 399AA genotype in a codominant model (AA vs GG; OR = 3.11 (1.06–9.10), ). In contrast, there were no significant differences between CRC patients and controls for the C194T polymorphism (C vs T; OR = 0.82 (0.52–1.31), ). These results are consistent with many similar studies, but further research is needed to verify whether the XRCC1 R194W and R399Q polymorphisms play a role in CRC etiology. The functional significance of these polymorphisms is unclear, but some studies suggest that they influence DNA repair capacity and, thus, cancer risk.

Dyskeratosis congenita is a rare disease characterized by bone marrow failure and a clinical triad of oral leukoplakia, nail dystrophy, and abnormal skin pigmen tation. The genetics of dyskeratosis congenita include mutations in genes involved in telomere maintenance, including TINF2. Here, we report a female patient who presented thrombocytopenia, anemia, reticulate hyperpigmentation, dystrophy in fingernails and toenails, and leukoplakia on the tongue. A histopathological study of the skin showed dyskeratocytes; however, a bone marrow biopsy revealed normal cell morphology. The patient was diagnosed with dyskeratosis congenita, but her family history did not reveal significant antecedents. Whole-exome sequencing showed a novel heterozygous punctual mutation in exon 6 from the TINF2 gene, namely, NM_001099274.1: c.854delp.(Val285 Alafs*32). An analysis of telomere length showed short telomeres relative to the patient’s age. The disease in this patient was caused by a germline novel mutation of TINF2 in one of her parents.