Human obesity is due to a complex interaction among environmental, behavioral, developmental and genetic factors, including the interaction of leptin (LEP) and leptin receptor (LEPR). Several LEPR mutations and polymorphisms have been described in patients with early onset severe obesity and hyperphagic eating behavior; however, some contradictory findings have also been reported. In the present study we explored the association of six LEPR gene polymorphisms in patients with morbid obesity. Twenty eight patients with morbid obesity and 56 non-obese Mexican Mestizo individuals were included. Typing of rs1137100, rs1137101, rs1805134, Ser492Thr, rs1805094 and rs1805096 LEPR polymorphisms was performed by PCR and allele specific hybridization. The LEPR Ser492Thr polymorphism was monomorphic with the presence of only the Ser492Thr-G allele. Allele C and genotype T/C for rs1805134 polymorphism were associated with susceptibility to morbid obesity (p = 0.02 and p = 0.03, respectively). No association was observed with any haplotype. Linkage disequilibrium (LD) showed that five polymorphisms (rs1137100, rs1137101, rs1805134, rs1805094 and rs1805096) were in absolute (D’ = 1) but none in perfect (r2 = 1) LD. Our results suggest that rs1805134 polymorphism could be involved in the development of morbid obesity, whilst none of the alleles of the LEPR gene, rs1137100, rs1137101, rs1805094 and rs1805096 were associated as risk factors. However, more studies are necessary to confirm or reject this hypothesis.

Intestinal mucins are the first line of defense against microorganisms. Although knowledge about the mechanisms involved in the establishment of intestinal protozoa is limited, there is evidence that these parasites produce lectin-like molecules and glycosidases, that exert both, constitutive and secretory functions, promoting the establishment of these microorganisms. In the present review, we analyse the main interactions between mucins of the host intestine and the four main protozoan parasites in humans and their implications in intestinal colonization. There are lectin-like molecules that contain complex oligosaccharide structures and N-acetylglucosamine (GlcNAc), mannose and sialic acid as main components, which are excreted/secreted by Giardia intestinalis, and recognized by the host using mannose-binding lectins (MBL). Entamoeba histolytica and Cryptosporidium spp. express the lectin galactose/N-acetyl-D-galactosamine, which facilitates their adhesion to cells. In Cryptosporidium, the glycoproteins gp30, gp40/15 and gp900 and the glycoprotein lectin CpClec are involved in protozoan adhesion to intestinal cells, forming an adhesion-attack complex. G. intestinalis and E. histolytica can also produce glycosidases such as β-N-acetyl-D-glucosaminidase, α-d-glucosidase, β-d-galactosidase, β-l-fucosidase, α-N-acetyl-d-galactosaminidase and β-mannosidase. In Blastocystis, α-D-mannose, α-D-glucose, GlcNAc, α-D-fucose, chitin and sialic acid that have been identified on their surface. Fucosidases, hexosaminidases and polygalacturonases, which may be involved in the mucin degradation process, have also been described in the Blastocystis secretoma. Similarly, symbiotic coexistence with the intestinal microbiota promotes the survival of parasites facilitating cell invasion and nutrients obtention. Furthermore, it is necessary to identify and characterize more glycosidases, which have been only partially described by in silico analyses of the parasite genome.

Cleft lip with or without cleft palate (CL/P) is one of the most common birth defects; it is a multifactorial disease affecting > 1/1,000 live births in Europe, and its etiology is largely unknown, although it is very likely genetic and environmental factors contribute to this malformation. Orofacial development is a complex process involving many genes and signaling pathways. Mutations in the gene for the interferon regulatory factor 6 (IRF6) cause a hereditary dominant malformation syndrome including CL/P, and polymorphisms are associated with non-syndromic CL/P (MIM 119530). Five SNPs at the locus with high heterozygosity in Caucasian populations were chosen for the present research due to their very strong association with CL/P. A case-parent trio study was performed using 292 samples from Mexico. Association with the rs1319435-C/C genotype (P = 0.02) was found in patients (73) as compared to pseudocontrols (219), while the genotype rs1319435-T/C was related with protection (P = 0.041) in the triad design. Significant over-transmission of the G allele for marker rs2235375 (P = 0.049) was found. Only the TACGT haplotype was diminished in the affected child, either in single (P = 0.0208) or double (P = 0.0208) dose. The pairwise analysis showed rs2235543 and rs2235371 were in strong linkage disequilibrium. These results point to a substantial contribution of IRF6 in the etiology of non-syndromic CL/P in a sample of the Mexican population.