The C677T variant in the MTHFR gene is considered to be an associated risk factor for neural tube defects. However, the association has not been found in some ethnic groups. In order to assess the association between neural tube defects and the C677T variant, we determined the frequency of this variant in the MTHFR gene in the State of Yucatan, Mexico, where neural tube defects are highly prevalent. The study was performed on 65 subjects with spine bifida, 60 of their mothers and 110 control subjects. The presence of the C677T variant was determined by amplification and digestion with HinF1 of each subject's DNA. Genotypic and allelic frequencies were calculated for all groups. We did not observe any statistically significant difference in the genotypic or allelic frequencies between cases and controls for any of the groups studied (p > 0.05), suggesting that the thermolabile variant C677T is not an associated risk factor neither for the development of neural tube defects nor for mothers to have affected offspring in the population from Yucatan. Interestingly, the frequency of the C677T variant (54%) obtained in the Yucatan population is one of the highest reported (p < 0.01) and confirmed the high frequency of this allele throughout Mexico.

Most cases of KTW syndrome are sporadic. However, in a few, other family members have some clinical manifestations of the syndrome, and an autosomal dominant mode of inheritance has been suggested. In this paper we present a family with an affected child who has large skin hemangiomata, overgrowth of the right leg, and severe heart defects. Her mother has a large capillary hemangioma on the left side of back and has developed severe varicosities in both lower extremities. The maternal grandmother developed severe varicosities in her legs at a young age. The clinical signs found in the mother represent a milder phenotype and might be explained as variable expressivity of the syndrome. The family tree supports autosomal dominant inheritance. © 1996 Wiley‐Liss, Inc.

Objectives Genetic variation of the fat mass and obesity associated gene (FTO) has been identified as a risk factor for obesity and obesity traits. Distribution of FTO single nutleotide polymorphisms (SNPs) rs1421085T>C, rs9939609T>A, rs8057044G>A and copy number variation (CNV) was evaluated in association with childhood obesity or overweight status in children with Mayan ethnicity. Methods We included 318 school‐aged children with obesity or overweight status (body mass index [BMI]: >85th percentile) and 303 children with normal weight (BMI: 15th‐85th percentile). Genotyping was performed using real‐time polymerase chain reaction (RT‐PCR) with TaqMan probes. The cross‐sectional study was carried out using univariate and multivariate logistic regression models adjusted for gender. Results FTO‐SNP rs1421085 showed significant differences between children with obesity and children with normal weight for the heterozygous genotype (P = 0.003) and for allele frequencies (P = 0.023). Adjusting by gender, significant differences were found in frequencies of the hetezygous genotype of SNPs rs9939609 (P = 0.023) and rs1421085 (P = 0.003) as well as in allele frequencies (P = 0.042 and P = 0.013, respectively) between girls with obesity and girls without obesity. In contrast, SNP rs8057044 was significantly different only between heterozygous overweight versus normal weight boys (P = 0.035) and for the allele frequency of rs8057044 (P = 0.021). The mean relative CNV was significantly higher in male overweight children than in boys with normal weight (P = 0.000). Conclusions The FTO SNP rs1421085 is a genetic factor associated with obesity in Mayan school‐aged children. FTO SNPs rs1421085 and rs9939609 affect genetic susceptibility for obesity only in girls, whereas, SNP rs8057044 and CNV are associated with overweight status only in boys.

The polymorphism A1298C-MTHFR is not associated with NTDs, except for mothers, suggesting only a maternal association with having NTD-affected offspring in the Yucatan population. The frequency of allele C in the control population was 10%, which is significantly lower than in other reported control populations worldwide (p < .01).

Part of the work agenda of international health authorities is to define the clinical spectrum of the congenital Zika syndrome (CZS) in different territories. We describe the clinical variability that gave rise to the suspicion of CZS in 3 newborn patients in the south of Mexico with active transmission of Zika. All of them presented Zika RNA by reverse transcription-polymerase chain reaction and positive antibodies for IgM by enzyme-linked immunosorbent assay. None of the mothers tested positive for active viremia, only one mother had Zika-symptoms and titers of Zika-positive IgM. Intrauterine growth restriction, brain disruption sequence, and intracranial calcifications are the clinical characteristics common in all. One patient had neural tube defect and other, arthrogryposis. Because the majority of pregnant women will be asymptomatic to Zika, we must be alert to the clinical variability of the birth defects associated to pregnancy Zika infection. Reports of clinical cases encourage the medical community to make diagnostic decisions.