A MCP-1 promoter polymorphism at G-2518A is associated with spontaneous preterm birth

A case-control association of RANTES (-28C >G) and CCR5-Delta32 polymorphisms with Parkinson's disease in Indians

Recent studies have suggested that chemokines and their receptors are involved in several neurodegenerative disorders. Also, numerous lines of evidence have indicated that inflammatory processes are involved in the pathogenesis of Parkinson's disease (PD). We have examined whether single nucleotide polymorphisms at the genes encoding chemokines RANTES (-28 C > G), RANTES (-403 A > G) MCP-1 (-2518 A > G), and chemokine receptors CCR2 (+190 G > A) and CCR5 (-Δ32) were associated with sporadic PD risk in the Indian population. This pilot case-control association study included 97 PD patients and 100 control subjects, who were all genotyped with PCR-RFLP for the five polymorphisms. There was no statistically significant difference in the genotype frequencies between the cases and controls for the MCP1 (-2518 A > G), RANTES (-403 A > G) and CCR2 (+190 G > A) polymorphisms. However, the results revealed a significant difference in the frequency of the heterozygous CG genotype for the RANTES (-28 C > G) polymorphism (OR = 0.49, p = 0.03) between the cases and controls. A negative association was demonstrated in the dominant model where, compared with the GG genotype, a higher frequency of the GC + CC genotype was observed in the controls. Also, a statistically significant higher frequency of the CCR5 heterozygous genotype WT/Δ32 in the controls was observed (OR = 0.31, p = 0.04). Combined genotype analysis revealed that the allele combination of G-A-G-C of CCR2 (+190G > A), MCP-1 (-2518 A/G), RANTES (-403 A/G) and RANTES (-28 C/G) respectively had a risk association with PD (OR = 6.18, p = 0.005).

Spontaneous preterm birth: advances toward the discovery of genetic predisposition

Evidence from family and twin-based studies provide strong support for a significant contribution of maternal and fetal genetics to the timing of parturition and spontaneous preterm birth. However, there has been only modest success in the discovery of genes predisposing to preterm birth, despite increasing sophistication of genetic and genomic technology. In contrast, DNA variants associated with other traits/diseases have been identified. For example, there is overwhelming evidence that suggests that the nature and intensity of an inflammatory response in adults and children are under genetic control. Because inflammation is often invoked as an etiologic factor in spontaneous preterm birth, the question of whether spontaneous preterm birth has a genetic predisposition in the case of pathologic inflammation has been of long-standing interest to investigators. Here, we review various genetic approaches used for the discovery of preterm birth genetic variants in the context of inflammation-associated spontaneous preterm birth. Candidate gene studies have sought genetic variants that regulate inflammation in the mother and fetus; however, the promising findings have often not been replicated. Genome-wide association studies, an approach to the identification of chromosomal loci responsible for complex traits, have also not yielded compelling evidence for DNA variants predisposing to preterm birth. A recent genome-wide association study that included a large number of White women (>40,000) revealed that maternal loci contribute to preterm birth. Although none of these loci harbored genes directly related to innate immunity, the results were replicated. Another approach to identify DNA variants predisposing to preterm birth is whole exome sequencing, which examines the DNA sequence of protein-coding regions of the genome. A recent whole exome sequencing study identified rare mutations in genes encoding for proteins involved in the negative regulation (dampening) of the innate immune response (eg, CARD6, CARD8, NLRP10, NLRP12, NOD2, TLR10) and antimicrobial peptide/proteins (eg, DEFB1, MBL2). These findings support the concept that preterm labor, at least in part, has an inflammatory etiology, which can be induced by pathogens (ie, intraamniotic infection) or "danger signals" (alarmins) released during cellular stress or necrosis (ie, sterile intraamniotic inflammation). These findings support the notion that preterm birth has a polygenic basis that involves rare mutations or damaging variants in multiple genes involved in innate immunity and host defense mechanisms against microbes and their noxious products. An overlap among the whole exome sequencing-identified genes and other inflammatory conditions associated with preterm birth, such as periodontal disease and inflammatory bowel disease, was observed, which suggests a shared genetic substrate for these conditions. We propose that whole exome sequencing, as well as whole genome sequencing, is the most promising approach for the identification of functionally significant genetic variants responsible for spontaneous preterm birth, at least in the context of pathologic inflammation. The identification of genes that contribute to preterm birth by whole exome sequencing, or whole genome sequencing, promises to yield valuable population-specific biomarkers to identify the risk for spontaneous preterm birth and potential strategies to mitigate such a risk.

[Association between tumor necrosis factor-α G-308A polymorphisms and genetic susceptibility to spontaneous preterm birth]

OBJECTIVE

To study the association between tumor necrosis factor-α (TNF-α) G-308A polymorphisms and genetic susceptibility to spontaneous preterm birth (SPTB).

METHODS

The case group enrolled 753 SPTB infants and the control group included 681 term infants. TNF-α G-308A polymorphisms were genotyped using Sequenom MassARRAY®SNP.

RESULTS

The frequencies of the allele (G and A) in the case and control groups were not significantly different (P=0.35). The frequencies of the genotypes (GG, GA and AA) in the case and control groups were not significantly different (P=0.64). The logistic regression analysis found that TNF-α G-308A was not associated with genetic susceptibility to SPTB (OR=0.85; 95%CI: 0.61-1.19; P=0.35).

CONCLUSIONS

There is no association between the polymorphisms of TNF-α G-308A and the genetic susceptibility to SPTB.

[Association between interleukin-1β C+3953T and genetic susceptibility to spontaneous preterm birth: a case-control study]

OBJECTIVE

To study the association between interleukin-1β (IL-1β) C+3953T and genetic susceptibility to spontaneous preterm birth (SPTB).

METHODS

In this case-control study, 753 SPTB neonates were enrolled in the case group and 681 full-term neonates were enrolled in the control group. The latest Sequenom MassARRAY®SNP detection technique was used for the typing of single nucleotide polymorphisms (SNP) of IL-1β C+3953T.

RESULTS

Compared with those carrying CC genotype of IL-1β C+3953T, the neonates who carried at least one T allele (CT+TT genotype) had significantly increased risks of SPTB, SPTB complicated by premature rupture of membranes, and mild preterm birth.

CONCLUSIONS

In the Chinese population, IL-1β C+3953T has significant genetic association with an increased risk of SPTB. The identification of this SNP helps to prevent SPTB and clarify the causes and pathogenesis of SPTB.

The CD38 genotype (rs1800561 (4693C>T): R140W) is associated with an increased risk of admission to the neonatal intensive care unit

BACKGROUNDS

Preterm birth (PTB)/admission to the neonatal intensive care unit (NICU) is a complex disorder associated with significant neonatal mortality and morbidity and long-term adverse health consequences. Multiple lines of evidence suggest that genetic factors play an important role in its etiology.

AIM

Given the role of CD38 in term delivery through oxytocin (OXT) release, we hypothesized that OXT signaling may play a role in the etiology of PTB/admission to the NICU. This study was designed to identify genetic variation in the CD38-oxytocin pathway associated with PTB/admission to the NICU.

METHODS

To identify common genetic variants predisposing individuals to PTB/admission to the NICU, we genotyped two single nucleotide polymorphisms (SNPs) in the CD38-oxytocin pathway in 63 case mothers, 55 control mothers, and 188 female volunteers in Nara Medical University Hospital, Japan.

RESULTS

Maternal genetic effect analysis of the SNP genotype data revealed a significant association between an SNP in CD38 (rs1800561 (4693C>T): R140W), which was reported to be correlated with diabetes and autism, and the risk of NICU admission. On the other hand, an SNP in the oxytocin receptor (OXTR) (rs2254298) showed no correlation with the risk of NICU admission.

CONCLUSION

Our study points to an association between maternal common polymorphisms in the CD38 (rs1800561) gene in Japanese women and susceptibility to PTB/admission to the NICU. Future studies with larger sample sizes are needed to confirm the findings of this study.