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Our study investigated the role of MTHFR C677T and A1298C variants in infants with neural tube defects (NTDs) from western Mexico. Using TaqMan allelic discrimination assay, we genotyped 101 live-born patients with NTDs (cases) and 247 controls. Our findings do not support that homozygosity or heterozygosity for the variants C677T and A1298C in the MTHFR gene are associated with NTDs in infants. However, since we have the highest worldwide frequency of homozygotes for the MTHFR C677T variant, we cannot rule out that our propensity for NTDs may be related to how such gene variant interacts with other factors, mainly with our secular patterns of inappropriate folate intake.

Background Mexican mestizo population has a pluriethnic mixture of Amerindian, European and African ancestry, predominant in most Latin American countries. Until now, there are no reports about hair characteristics in this population, necessary to define normal values, for hair diseases evaluation and comparison among other ethnic groups. Methods The VivoSight® swept-source multibeam optical coherence tomography system was used to evaluate hair diameter and shape in 30 females. Three hair samples from each volunteer were measured transversely along three distances, generating nine cross-sectional images, two measurements per image and 18 measurements per patient for a total of 540 diameter measurements. Results Minimum hair diameter (n = 540) was 0.06 mm while maximum was 0.14 mm. Mean diameter was 0.10 ± 0.01 mm as compared with Asian hair, which ranges from 0.08 mm to 0.12 mm. On morphological analysis, Mexican Mestizo hair tends to have a round shape with homogenous diameters, resembling Caucasian and Asian hair. Conclusion Mexican hair is similar to Asian hair in diameter and shape and can be classified as 'thick' hair, which make it more resistant and with more volume. Cosmetic products intended to improve hair care in this population must to consider this characteristic.

Dermochondrocorneal Dystrophy (OMIM 221800) is a very rare disease first described by Francois in 1949. It is characterized by the appearance of skin nodules, osteochondral deformities, and corneal opacities during childhood. Only a few cases have been reported. There is uncertainty about the inheritance pattern and no gene or genes have been associated to this disease. We report a patient from Mexican mestizo origin with the classic manifestations of Dermochondrocorneal Dystrophy. We perform a multidisciplinary assessment in order to contribute to the knowledge of the clinical presentation of this uncommon condition. Among the few documented patients, this is the third patient of Mexican ancestry reported with this syndrome.

El labio leporino no sindromico con o sin paladar hendido es un defecto congenito craneofacial comun que afecta aproximadamente a 1 de cada 1.000 nacidos vivos en todo el mundo. Entre los genes asociados con esta condicion se encuentran IRF6, MSX1, TGFA, TGFB3 y PVRL1, aunque solo se ha informado de la asociacion de IRF6 [Dixon et al., 2011]. Recientemente, se informo de una fuerte asociacion genetica de una region de 640 kb de 8q24 a NS CL - P [Birnbaum et al., 2009]. Hasta la fecha, ha habido poca informacion sobre los factores ambientales y geneticos asociados con NS CL - P en poblaciones mestizas mexicanas. Por consiguiente, se realizo un estudio de casos y controles que analizo la asociacion de 17 variantes de cinco genes candidatos (IRF6, MSX1, TGFA, TGFB3 y PVRL1) y la region cromosomica 8q24, con NS CL - P, utilizando ambos analisis de asociacion simple y haplotipo . Tambien se analizaron los efectos de las interacciones entre todas las variantes geneticas y la ingesta materna de acido folico en el riesgo de NS CL - P.

Background: Parkin mutations in patients with early-onset Parkinson's disease (EOPD) are estimated to occur in 49% of familial cases and 18% of sporadic cases. Methods: We analyzed the entire sequence-coding region and dosage mutations of parkin in 63 Mexican-mestizo EOPD patients and 120 controls. Results: Parkin mutations were present in 34 patients (54.0%). Exon rearrangements, predominantly spanning exons 9 and 12 (31.7% and 19.0%, respectively) were present in 32 patients, with 17.5% carrying simple heterozygous and 25.4% carrying compound heterozygous parkin mutations. Conclusions: A higher frequency of parkin exon rearrangements than of sequence mutations was observed. Patients with parkin exons 9 and 12 rearrangements showed a later age at onset than did cases with other regions affected (40.3 ± 4.5 vs 30.1 ± 8.8; P = .005), suggesting a mutational hot spot in the etiology of Mexican-mestizo patients with EOPD. To our knowledge, this study represents the largest sampling of Mexican-mestizo patients with EOPD cases for which parkin sequence and dosage alterations were analyzed. © 2012 Movement Disorder Society

SUMMARY Aim: The DD genotype of angiotensin-converting enzyme (ACE) has been suggested as a major contributor of diabetic nephropathy in several populations. The purpose of the present study was to determine whether micro/macroalbuminuria is associated with ACE insertion/deletion (I/D) polymorphism in Mexican Mestizos with type 2 diabetes mellitus. Methods: A total of 435 patients with type 2 diabetes mellitus, of whom 233 had albuminuria, were characterized for the ACE I/D polymorphism by the polymerase chain reaction method. Results: Clinical and biochemical characteristics and frequencies according to DD, ID and II genotypes in patients with and without albuminuria showed no significant differences. However, only females with micro/macroalbuminuria showed higher frequency of a DD genotype than those without albuminuria (27.9%, 21.2% and 10.5%, respectively; P ≤ 0.044). In addition, female patients with macroalbuminuria without dialysis showed no significant differences with patients undergoing dialysis. Conclusion: The ACE DD genotype is a risk factor for the development of renal disease in Mexican Mestizo females with type 2 diabetes, indicating a possible DD genotype-associated sex effect in renal disease.

The aim of the present study was to reevaluate the distribution of HLA antigens in Mexican Mestizos since, in our previous report, very few specificities were explored for this population. The Mestizos are primarly a mixture of Caucasians (Spaniards) and Mexican Indians and account at the present time for about 95% of the total Mexican population. A and B antigens were typed on isolated cells using a microlymphocytotoxicity technique. Antigen, gene and haplotype frequencies were calculated including the significance for delta values. The results clearly showed that the HLA distribution differs from other ethnic groups and the predominant antigens are A2, A9, B5, Bw35 and B40, but the general pattern clearly shows the participation in genetical composition of Spanish and Mexican Indian backgrounds. The most frequent haplotypes were A2-B5, A9-Bw35, A9-B40 and A2-B40, which are also the most common in some Mongoloid populations.

Two previous surveys of ankylosing spondylitis (AS) in Mexican Mestizos found HLA-B27 frequencies of 68.6% and 78% and a relative risk (RR) of 37.05 and 120.88, respectively. We examined an additional group of Mexican Mestizos with AS and found an HLA-B27 frequency of 80.77% and a RR of 99.24. Our results are statistically comparable to the previous studies, and they suggest that the Mexican Mestizo is similar to the Spaniard in regards to AS and HLA-B27 association.

Several polymorphisms in the CYP1A1 locus have been identified and their genotypes appear to exhibit population frequencies that depend on ethnicity. We studied two CYP1A1 polymorphic sites (position 4889 and 6235) in a group of 212 unrelated healthy individuals belonging to three different Mexican populations (106 Mexican Mestizos, 52 Teenek and 54 Mayos). Comparison among Mexican populations showed increased frequency of the *Ile allele (A on position 4889) in Mexican Mestizos when compared to Amerindians (p

This study compares genetic polymorphisms at the D1S80 and HLA-DQA1 loci in three Mexican Mestizo populations from three large states (Nuevo Leon, Jalisco, and the Federal District). Allele frequency distributions are relatively homogenous in the three samples; only the Federal District population shows minor differences of the HLA-DQA1 allele frequencies compared with the other two. In terms of genetic composition, these Mestizo populations show evidence of admixture with predominantly Spanish-European (50-60%) and Amerindian (37-49%) contributions; the African contribution (1-3%) is minor. Together with the observation that in Nuevo Leon, the admixture estimates based on D1S80 and HLA-DQA1, are virtually the same as those reported earlier from blood group loci, suggests that DNA markers, such as D1S80 and HLA-DQA1 are useful for examining genetic homogeneity/heterogeneity across Mestizo populations of Mexico. The inverse relationship of the proportion of gene diversity due to population differences (Gst) to within population gene diversity (Hs) is also consistent with theoretical predictions, supporting the use of these markers for population genetics studies. Am. J. Hum. Biol. 14:257-263, 2002. © 2002 Wiley-Liss, Inc.

Human leukocyte antigen-B*9550 is a novel allele identified in a Mexican Mestizo bone marrow donor from Veracruz.

The A*29:47 allele was identified in a Mexican Mestizo unrelated bone marrow donor from the state of Hidalgo.

Three sibs from a Mexican mestizo family affected with a spondylo-epi-metaphyseal dysplasia were studied. The clinical, radiological, and genetic findings were similar to those previously described in Venezuelan Indians of the Irapa tribe. The present patients permit confirmation of the syndrome and provide evidence for autosomal recessive inheritance. Genetic drift is postulated.