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Background: Sudden infant death syndrome (SIDS) is the leading cause of death among infants aged between one month and one year. Altered enzyme activities or expression of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) have been observed in SIDS patients that might lead to disturbed autonomic function and, together with other risk factors, might trigger SIDS. To explore the contribution of AChE and BChE from a genomic viewpoint, we sought to investigate the association between SIDS and selected single nucleotide polymorphisms (SNPs) in the ACHE and BCHE genes. Methods: In this case-control study, 13 potentially regulatory SNPs were selected from ACHE and BCHE and were genotyped in 201 SIDS cases and 338 controls. The association of SIDS with the 11 successfully genotyped candidate variants was examined using statistical analyses of overall or stratified cases and haplotype analyses. Results: No significant overall associations were observed between SIDS and ACHE and BCHE variants in allele, genotype, and haplotype analyses. In subgroup analyses, eight variants were found to be nominally associated with SIDS, though these associations did not remain statistically significant after correction for multiple comparisons. One haplotype (T-C-G-C-C in rs3495-rs1803274-rs1355538-rs2048493-rs1126680) of BCHE was associated with the female SIDS subgroup (57.3% in controls vs. 46.3% in female SIDS cases, p = 0.010). Conclusions: The selected variants in ACHE and BCHE were not overall associated with SIDS in this study, and thus cannot generally explain the previously reported dysregulation of enzyme activities in SIDS. However, some evidence of association in subgroups and a possible contribution of variants other than those tested here would need to be explored in larger studies. [ABSTRACT FROM AUTHOR]

Objectives: Disturbances of the central nervous system and immune system are thought to play a role in sudden infant death syndrome (SIDS). Dysregulated expression of sodium (Na+)/hydrogen (H+) exchanger 3 (NHE3) in the brainstem and of interleukin 13 (IL13) in the lungs has been observed in SIDS. An association of single-nucleotide polymorphisms (SNPs) in NHE3 and IL13 with SIDS has been proposed, but controversial results were reported. Therefore, there is a need to revisit the association of SNPs in NHE3 and IL13 with SIDS. Methods: Genotyping of rs71597645 (G1131A) and rs2247114 (C2405T) in NHE3 and rs20541 (+ 4464A/G) in IL13 was performed in 201 SIDS cases and 338 controls. A meta-analysis was performed after merging our data with previously published data (all from European populations). Results: Polymorphisms rs2247114 (NHE3) and rs20541 (IL13) were significantly associated with SIDS overall and in multiple subgroups, but no association was found for rs71597645 (NHE3). After combining our data with previously published data, a fixed-effect meta-analysis showed that rs2247114 in NHE3 retained a significant association with SIDS under a recessive model (OR 2.78, 95%CI 1.53 to 5.06; p = 0.0008). Conclusion: Our findings suggest an association of NHE3 variant rs2247114 (C2405T), though not rs71597645 (NHE3), with SIDS. A potential role of rs20541 (IL13) still has to be elucidated. Especially NHE3 seems to be an interesting topic for future SIDS research. [ABSTRACT FROM AUTHOR]

Aim: Impaired resilience to stress may be a factor in sudden infant death syndrome (SIDS). However, no comprehensive studies have been performed on polymorphisms that are relevant to the hypothalamic–pituitary–adrenal (HPA) axis, which regulates the stress hormone cortisol. Methods: We analysed 22 relevant single nucleotide polymorphisms (SNPs) in 206 anonymised SIDS cases who died at a mean of 131 days (range: 5–343) and 256 adult controls who were recruited from paternity testing cases. Additional stratified analyses were performed for sex, age and season of death. Both the cases and the controls were Caucasian. Results: Variants for rs2235543 (HSD11B1) and rs3779250 (CRHR2) were associated with SIDS in the overall analysis, and borderline for rs2446432 (CRH), at least before corrections for multiple testing. A combination of these three variants was observed in 52.9% of SIDS cases but only 43.0% of controls (p = 0.039). Five or more variants showed an association in the subgroups. Conclusion: Our findings suggest that the HPA axis influences SIDS and supports the hypothesis that an inadequate stress response may add to the risk. The associated variants for rs2235543, rs3779250 and rs2446432 appeared to decrease the cortisol concentration and impair an appropriate stress response. [ABSTRACT FROM AUTHOR]

Increasing evidence suggests that brain edema might play an important role in the pathogenesis of sudden infant death syndrome (SIDS) and that variants of genes for cerebral water channels might be associated with SIDS. The role of the sulfonylurea receptor 1 (SUR1)–transient receptor potential melastatin 4 (TRPM4) non-selective cation channel in cerebral edema was demonstrated by extensive studies. Therefore, we hypothesized that variants at genes of the SUR1-TRPM4 channel complex might be linked to SIDS. Twenty-four polymorphisms in candidate genes involved in the SUR1-TRPM4 non-selective cation channel were investigated in 185 SIDS cases and 339 controls. One (rs11667393 in TRPM4) of these analyzed SNPs reached nominal significance regarding an association with SIDS in the overall analysis (additive model: p = 0.015, OR = 1.438, 95% CI = 1.074–1.925; dominant model: p = 0.036; OR = 1.468, 95% CI = 1.024–2.106). In the stratified analysis, further 8 variants in ABCC8 (encoding SUR1) or TRPM4 showed pronounced associations. However, none of the results remained significant after correction for multiple testing. This preliminary study has provided the first evidence for a genetic role of the SUR1-TRPM4 complex in the etiology of SIDS, and we suggest that our initial results should be evaluated by further studies. [ABSTRACT FROM AUTHOR]

Background: There is evidence that inflammation plays a role in the etiology of sudden infant death syndrome (SIDS). Immune system dysregulation seems to be the background of higher infection susceptibility in SIDS infants. This phenotype is possibly determined by genetic factors. Methods: Twenty-three single nucleotide polymorphisms (SNPs) in the following 13 candidate genes governing the immune system were successfully genotyped in 251 Caucasian SIDS cases and 336 controls from Germany: ADAR1, CSF2RB, DDX58, IFNA1, IFNA21, IFNA8, IFNAR2, IFNG, IL6, MX2, OAS1, OAS3, and TNFA. Associations between genotypes and SIDS were then statistically evaluated using logistic regression analyses. Results: Overall analysis revealed statistically significant results for two variants in interferon gamma (IFNG) (rs2069705: OR 1.40 (1.07; 1.83), p = 0.01; and rs2069727: OR 0.75 (0.59; 0.96), p = 0.02) and for one variant in interferon alpha 8 (IFNA8) (rs1330321: OR 1.85 (1.06; 3.21), p = 0.03). Haplotype analyses identified a three-marker risk IFNG haplotype rs2069727-rs2069718-rs2069705 associated with SIDS (OR = 1.62, 95% CI 1.23–2.13; p = 0.0003). Subgroup associations were found for variants in adenosine deaminase acting on RNA1 (ADAR1), 2′,5′-oligoadenylate synthetase-1 (OAS1) and colony stimulating factor 2 receptor beta common subunit (CSF2RB). Conclusion: In summary, this large study of 251 SIDS cases for common variants in 13 candidate genes governing the immune system has provided first evidence for a role of IFNG in the etiology of SIDS and should stimulate further research into the clinicopathological relevance of immunomodulatory genes for this fatal syndrome. [ABSTRACT FROM AUTHOR]

Introduction: Sudden infant death syndrome (SIDS) is a multifactorial syndrome and we believe that an inefficient respiratory response to certain homeostatic stressors, such as hypoxia and hypercapnia, is a key factor in the etiology of SIDS. Hence, we genotyped two single nucleotide polymorphisms (SNPs) in genes of importance for respiratory control: P2RY1 (adenosine diphosphate/adenosine triphosphate receptor) and SSTR2 (somatostatin receptor). Methods: Two SNPs, Rs1466113 (C > G dimorphism in SSTR2) and rs701265 (A > G dimorphism in P2RY1), were typed in 175 SIDS cases and 195 controls and 275 SIDS cases and 338 controls, respectively. Genotyping was performed using TaqMan technology. Results: The determined genotype frequencies were SSTR2: CC (14.4 %), CG (49.7 %), GG (35.9 %) in controls and CC (17.1 %), CG (49.1 %), and GG (33.8 %) in SIDS; P2RY1: AA (70.6 %), AG (28.7 %), GG (0.7 %) in SIDS and AA (68.3 %), AG (27.9 %), and GG (3.8 %) in the control group. For rs701265 in P2RY1, homozygous G carriers were significantly more frequent in the control group ( p = 0.02). Conclusion: We think that allele G provides a protective effect in events of ventilatory stress. Moreover, the significant lack of P2Y1 G allele homozygotes in the SIDS group shows that respiratory response plays an important role in the etiology of SIDS. Thus, we believe it is worthwhile to further investigate functional polymorphisms within genes that are involved in respiratory control in the future. [ABSTRACT FROM AUTHOR]

Aim: Recent research suggests that genetic variance determining the strength of noradrenergic transmitting might contribute to the aetiology of SIDS. We have typed 2 functional polymorphisms of relevance for both biosynthesis and catabolism of noradrenalin: The Val158Met single-nucleotide polymorphism (SNP) of the Catechol- O-methyl transferase gene (COMT) and the 1021C/T SNP of the dopamine dehydroxylase gene (DBH). Methods: COMT and DBH were typed in 171 and 196 SIDS cases and 213 and 244 controls, respectively, using PCR followed by digestion with restriction enzymes. Typing was performed using a QIAxcel automatic electrophoresis unit. Results: Both SNPs were in Hardy-Weinberg equilibrium, and for none of these polymorphisms, an association with SIDS could be demonstrated. The allelic frequencies of the DBH locus were C: 78.32% and T: 21.68% in SIDS and C: 77.66% and T: 22.34% in controls. For the COMT locus, the allelic frequencies were A: 51.17% and G: 48.83% in SIDS and A: 52.82% and G: 47.18% in controls. Conclusion: Despite these negative results, the noradrenergic system is still an attractive candidate as modulator of SIDS risk to our eyes. There are several genes involved in this system that have not been studied up to now. [ABSTRACT FROM AUTHOR]