Evaluation of the association of polymorphisms in EYA 1 , environmental factors, and non‐syndromic orofacial clefts in Western Han Chinese

Family history in non-syndromic orofacial clefts: Is there a pattern?

OBJECTIVE

To survey the frequency and pattern of family history for non-syndromic orofacial clefts (NSOFC). Initial hypothesis: more complex forms have a higher frequency of positive family history.

MATERIALS AND METHODS

A retrospective study was carried with 2,668 subjects with three different types of clefts (CL Group (cleft lip), CLP Group (cleft lip and palate), and CP group (cleft palate)); family history information was collected. The Chi-square (X² ) and Z-test were used.

RESULTS

A positive family history was found in 31% of the sample. The CLP Group had highest percentage and highest proportion of affected relatives, being these factors statistically significant when compared to the CP Group. Comparisons between the CLP Male and CL Male with CP Male were statistically significant. First-degree kinship was the most frequently found.

CONCLUSIONS

The initial hypothesis was confirmed, subjects with CLP had the highest percentage of positive family history, the highest proportion of affected relatives and had more affected relatives in comparison with CP. It is more common to find affected relatives in the CLP Male and CL Male groups when compared with CP Male. CLP and CP groups present a pattern of occurrence of the type of cleft in the family.

Gene-environment interactions between air pollution and biotransformation enzymes and risk of birth defects

Genetic and environmental factors have been observed to influence risks for birth defects, though few studies have investigated gene-environment interactions. Our aim was to examine the interaction terms of gene variants in biotransformation enzyme pathways and air pollution exposures in relation to risk of several structural birth defects. We evaluated the role of ambient air pollutant exposure (nitrogen dioxide [NO2 ], nitrogen oxide, carbon monoxide, particulate matter <10 [PM10 ] and <2.5 [PM2.5 ] microns) during pregnancy and 104 gene variants of biotransformation enzymes from infant bloodspots or buccal cells in a California population-based case-control study in 1997-2006. Cases included cleft lip with or without cleft palate (N = 206), gastroschisis (N = 94), tetralogy of Fallot (N = 69), and dextro-transposition of the great arteries (d-TGA; N = 40) and were compared to 208 nonmalformed controls. Overall, the results were not consistent, though did highlight some associations for further investigation as indicated by Wald chi-square test p value <.1. Increased risk of cleft lip was associated with exposure to high PM10 and two CYP gene variants. High PM2.5 and the variant of SLCO1B1 was associated with increased risk of teratology of Fallot. Higher NO2 and two gene variants, CYP2A6 and SLC01B1, were associated with increased risk of d-TGA. Results for gastroschisis were inconsistent in direction and across pollutants. These exploratory results suggest that some individuals based on their genetic background may be more susceptible to the adverse effects of air pollution.

Environmental Risk Factors for Nonsyndromic Cleft Lip and/or Cleft Palate in Xinjiang Province, China: A Multiethnic Study

OBJECTIVE

To determine the risk factors of the occurrence of nonsyndromic cleft lip and/or cleft palate (NSCL/P) in Xinjiang Province, China.

DESIGN

The study included 359 patients of NSCL/P and 310 controls. Information about sociodemographic characteristics, lifestyle behaviors, negative life events, possible environmental hazards exposures, and use of supplementations were collected from cases and controls. Both t test and χ² tests were used for group comparisons. Multivariable logistic regression was used to estimate the independent associations between environmental risk factors and the presence of NSCL/P. The receiver operating characteristic curve was used to establish the predictive variables for the occurrence of NSCL/P.

RESULTS

The results showed that maternal pesticide exposure (odds ratio [OR] = 11.40, 95%CI: 5.40-24.10), antibiotic drugs use (OR = 1.32, 95%CI: 1.14-1.53), paternal smoking (OR = 3.30, 95%CI: 1.87-5.83), threatened abortion (OR = 12.2, 95%CI: 3.29-45.25) were associated with increased risk of NSCL/P in offspring. In contrast, maternal moderate (OR = 0.43, 95%CI: 0.20-0.92) and middle physical workload (OR = 0.48, 95%CI: 0.0.23-0.97), vitamin-B complex supplementations (OR = 0.11, 95%CI: 0.03-0.41), calcium and iron (OR = 0.27, 95%CI: 0.08-0.90) supplementations were associated with reduced risk of NSCL/P in offspring. These variables together explain nearly 60% of the variation of occurrence of NSCL/P.

CONCLUSION

These findings from our study may help to develop primary prevention strategies for NSCL/P in Xinjiang.

[Association between platelet-derived growth factor-C single nucleotide polymorphisms and nonsyndromic cleft lip with or without cleft palate in Western Chinese population]

OBJECTIVE

To explore the association between two single nucleotide polymorphisms (SNPs), namely, rs4691383 and rs7667857, in the platelet-derived growth factor-C (PDGF-C) gene, the genotypes, environmental exposure factors, and nonsyndromic cleft lip with or without cleft palate (NSCL/P) in Western Chinese population.

METHODS

A total of 268 case-parent trios were selected, and two SNPs (rs4691383 andrs7667857) were genotyped by using polymerase chain reaction and restriction enzyme fragment length polymorphic method and direct sequencing method. Hardy-Weinberg equilibrium, linkage disequilibrium test, transmission disequilibrium test, and haplotype analysis were conducted to analyze the data. Meanwhile, the questionnaires on the epidemiology of cleft lip and palate filled by the included samples were collected, and the interaction between the genotypes of the two SNPs and environmental exposure factors was assessed by conditional logistic regression.

RESULTS

The A allele at rs4691383 and the G allele at rs7667857 of PDGF-C gene were over-transmitted for NSCL/P (P<0.05). No interaction effect was observed between the three environmental exposure factors (history of smoking/passive smoking, folic acid supplementation, and long-term inhalation of harmful environmental gases) and the PDGF-C genotypes among NSCL/P (P>0.05).

CONCLUSIONS

The rs4691383 and rs7667857 at PDGF-C gene are closely related to the occurrence of NSCL/P in Western Chinese population. However, the interaction between environmental exposure factors and PDGF-C genotypes is not obvious in the occurrence of NSCL/P.

TGFα/HinfI Polymorphisms Contribute to Nonsyndromic Cleft Lip and Palate in Turkish Patients

BACKGROUND

Nonsyndromic cleft lip with/without cleft palate (nsCL ± P) is one of the most common birth defects of complex etiology, occurring in ∼1/700 live births worldwide. A series of epidemiological studies were conducted to investigate the association between a transforming growth factor alpha (TGFα) polymorphism and nsCL ± P risk. The aim of this study was to investigate the association between the TGFα/HinfI polymorphisms and nsCL ± P in Turkish patients.

METHODS

One hundred fifty-five Turkish subjects were enrolled: 70 nsCL ± P patients and 85 unrelated control individuals. Genomic DNA was isolated from peripheral blood leukocytes, and molecular analysis of gene polymorphisms was carried out using polymerase chain reaction and restriction enzyme digestions.

RESULTS

We found significant difference between the TGFα gene HinfI allele frequencies of the controls and: 1) the occurrence of nonsyndromic cleft lip (p = 0.029,); 2) the occurrence of nonsyndromic cleft lip and palate (nsCL + P) cases (p = 0.024; and 3) the occurrence of both nsCL ± nsCLP cases (p = 0.0365). The association between age of parents, gender, maternal exposures, socioeconomic status and clefts was assessed in each group separately.

CONCLUSION

Our study indicates that the TGFα HinfI gene polymorphism might be associated with nsCL ± P susceptibility, thus contributing to the occurrence of nsCL ± P in Turkish patients. The relatively small sample size of our study is one limitation of our study, and future research with larger specimen sets from different ethnicities will be required to validate our findings.

Nucleotide Variants of the BH4 Biosynthesis Pathway Gene GCH1 and the Risk of Orofacial Clefts

A deficiency of GTP cyclohydrolase, encoded by the GCH1 gene, results in two neurological diseases: hyperphenylalaninaemia type HPABH4B and DOPA-responsive dystonia. Genes involved in neurotransmitter metabolism and motor systems may contribute to palatogenesis. The purpose of the study was to analyse polymorphic variants of the GCH1 gene as risk factors for non-syndromic cleft lip with or without cleft palate (NSCL/P). Genotyping of nine polymorphisms was conducted in a group of 281 NSCL/P patients and 574 controls. The GCH1 variant rs17128077 was associated with a 1.7-fold higher risk for NSCL/P (95 %CI = 1.224-2.325; p = 0.001). We also found a significant correlation between the rs8004018 and rs17128050 variants and an increased risk of oral clefts (p trend = 0.003 and 0.004, respectively). The best evidence of the global haplotype association was observed for rs17128050 and rs8004018 (p corr = 0.0152). This study demonstrates that the risk of NSCL/P is associated with variants of the GCH1 gene related to BH4 metabolism and provides some evidence of the relationships between morphological/functional shifts in the central nervous system and orofacial clefts.