Large-scale replication study identified multiple independent SNPs in RET synergistically associated with Hirschsprung disease in Southern Chinese population

High incidence of EDNRB gene mutation in seven southern Chinese familial cases with Hirschsprung's disease

PURPOSE

Hirschsprung's disease (HSCR) is the leading cause of neonatal functional intestinal obstruction, which has been identified in many familial cases. HSCR, a multifactorial disorder of enteric nervous system (ENS) development, is associated with at least 24 genes and seven chromosomal loci, with RET and EDNRB as its major genes. We present a genetic investigation of familial HSCR to clarify the genotype-phenotype relationship.

METHODS

We performed whole exome sequencing (WES) on Illumina HiSeq X Ten platform to investigate genetic backgrounds of core family members, and identified the possibly harmful mutation genes. Mutation carriers and pedigree relatives were validated by Sanger sequencing for evaluating the gene penetrance.

RESULTS

Four familial cases showed potential disease-relative variants in EDNRB and RET gene, accounting for all detection rate of 57.1%. Three familial cases exhibited strong pathogenic variants as frameshift or missense mutations in EDNRB gene. A novel c.367delinsTT mutation of EDNRB was identified in one family member. The other two EDNRB mutations, c.553G>A in family 2 and c.877delinsTT in family 5, have been reported in previous literatures. The penetrance of EDNRB variants was 33-50% according mutation carries. In family 6, the RET c.1858T>C (C620R) point mutation has previously been reported to cause HSCR, with 28.5% penetrance.

CONCLUSION

We identified a novel EDNRB (deleted C and inserted TT) mutation in this study using WES. Heterozygote variations in EDNRB gene were significantly enriched in three families and RET mutations were identified in one family. EDNRB variants showed an overall higher incidence and penetrance than RET in southern Chinese families cases.

Distribution of RET proto-oncogene variants in children with appendicitis

Background

In addition to patient‐related systemic factors directing the immune response, the pathomechanisms of appendicitis (AP) might also include insufficient drainage leading to inflammation caused by decreased peristalsis. Genetic predisposition accounts for 30%–50% of AP. M. Hirschsprung (HSCR), also characterized by disturbed peristalsis, is associated with variants in the RET proto‐oncogene. We thus hypothesized that RET variants contribute to the etiology of AP.

Methods

DNA from paraffin‐embedded appendices and clinical data of 264 children were analyzed for the RET c.135A>G variant (rs1800858, NC_000010.11:g.43100520A>G). In 46 patients with gangrenous or perforated AP (GAP), peripheral blood DNA was used for RET sequencing.

Results

Germline mutations were found in 13% of GAP, whereas no RET mutations were found in controls besides the benign variant p.Tyr791Phe (NC_000010.11:g.43118460A>T). In GAP, the polymorphic G‐allele in rs2435352 (NC_000010.11:g.43105241A>G) in intron 4 was underrepresented (p = 0.0317).

Conclusion

Our results suggest an impact of the RET proto‐oncogene in the etiology of AP. Mutations were similar to patients with HSCR but no clinical features of HSCR were observed. The pathological phenotypes in both populations might thus represent a multigenic etiology including RET germline mutations with phenotypic heterogeneity and incomplete penetrance.

Associations of CYP2B6 genetic polymorphisms with Hirschsprung's disease in a southern Chinese population

Background

Hirschsprung’s disease (HSCR) is an enteric nervous system birth defect partially caused by a genetic disorder. Single‐nucleotide polymorphisms (SNPs) of the cytochrome P450 family 2 subfamily B member 6 (CYP2B6) gene are reported to be associated with HSCR.

Methods

We evaluated the association of rs2054675, rs707265, and rs1042389 with HSCR susceptibility in southern Chinese children including 1470 HSCR patients and 1473 controls using the TaqMan SNP Genotyping Assay.

Results

rs2054675 C allele and the rs707265 G allele were risk SNPs for total colonic aganglionosis (OR = 1.82, 95% CI 1.29 ~ 2.55, P_adj < 0.001 and OR = 0.68, 95% CI 0.48 ~ 0.97, P_adj = 0.034). These results suggested that CYP2B6 rs2054675 and rs707265 polymorphisms were associated with increased susceptibility to the severe HSCR subtype in southern Chinese children.

Conclusion

We suggest that CYP2B6 rs2054675 and rs707265 polymorphisms are associated with increased susceptibility to the severe HSCR subtype in southern Chinese children.

Association of REarranged during Transfection (RET) c.73 + 9277T > C and c.135G > a Polymorphisms with Susceptibility to Hirschsprung Disease: A Systematic Review and Meta-Analysis

Background: Previous studies have suggested a close association between REarranged during Transfection (RET) c.73 + 9277T > C and c.135G > A polymorphisms and Hirschsprung disease (HSCR) susceptibility. The results are inconsistent and contradictory. Thus, we performed a meta-analysis to evaluate the association of RET c.73 + 9277T > C and c.135G > A polymorphisms with risk of HSCR.Methods: The eligible literatures were searched by PubMed, Google Scholar, EMBASE, and CNKI up to August 5 2019.Results: A total of 20 studies including 10 studies with 1136 cases and 2420 controls on c.73 + 9277T > C and 10 studies with 917 cases and 1159 controls on c.135G > A were selected. Pooled ORs revealed that c.73 + 9277T > C and c.135G > A polymorphisms were significantly associated with an increased risk of HSCR. Moreover, stratified analysis revealed that c.73 + 9277T > C and c.135G > A polymorphisms were associated with HSCR risk in Asian, Caucasian and Chinese populations.Conclusions: This meta-analysis result indicated that the RET c.73 + 9277T > C and c.135G > A polymorphisms were associated with susceptibility to HSCR.

Association between miR-492 rs2289030 G>C and susceptibility to Hirschsprung disease in southern Chinese children

OBJECTIVE

Hirschsprung disease (HSCR) originates from disruption of normal neural crest cell migration, differentiation, and proliferation during the fifth to eighth weeks of gestation. This results in the absence of intestinal ganglion cells in the distal intestinal tract. However, genetic variations affecting embryonic development of intestinal ganglion cells are unclear. Therefore, this study aimed to investigated the potential value of miR-492 rs2289030 G>C as a marker of susceptibility to HSCR.

METHODS

In this case-control study in southern Chinese children, we collected samples from 1473 controls and 1470 patients with HSCR. TaqMan genotyping of miR-492 rs2289030 G>C was performed by real-time fluorescent quantitative polymerase chain reaction.

RESULTS

Multivariate logistic regression analysis showed that there was no significant association between the presence of the miR-492 rs2289030 G>C polymorphism and susceptibility to HSCR by evaluating the values of pooled odds ratios and 95% confidence intervals. Similarly, among different HSCR subtypes, rs2289030 G>C was also not associated with HSCR in hierarchical analysis.

CONCLUSIONS

Our results suggest that the miR-492 rs2289030 G>C polymorphism is not associated with susceptibility to HSCR in southern Chinese children. These results need to be further confirmed by investigating a more diverse ethnic population of patients with HSCR.

miR-100 rs1834306 A>G Increases the Risk of Hirschsprung Disease in Southern Chinese Children

Background

Hirschsprung disease (HSCR) is a rare congenital gastrointestinal disease characterized by the absence of intestinal submucosal and myometrial ganglion cells. Recently, researches indicated that miR-100 regulated the growth, differentiation and apoptosis of neurons, and affected the functions of HSCR-associated pathways. While miR-100 rs1834306 A>G polymorphism was shown to modify the susceptibility to tumors, the association between this polymorphism and HSCR susceptibility is still unknown.

Methods

This was a case-control study consisting of 1470 HSCR cases and 1473 controls from southern China. DNA was genotyped by TaqMan real-time PCR. Odds ratios (ORs) and 95% confidence intervals (CIs) were used as statistical indicators.

Results

We found that miR-100 rs1834306 G allele and GG genotype significantly increased HSCR susceptibility (GG vs AA: adjusted OR=1.31, 95% CI=1.04-1.64, P=0.020; G vs A: adjusted OR=1.12, 95% CI=1.01-1.25, P=0.041; GG vs AA/AG: adjusted OR=1.30, 95% CI=1.07-1.59, P=0.010). In the stratified analysis, miR-100 rs1834306 GG genotype carriers had higher risk to develop HSCR in all clinical subtypes when compared with those with AA/AG genotypes, and OR was rising with HSCR aggravation (SHSCR: adjusted OR=1.28, 95% CI=1.03-1.59, P=0.029; LHSCR: adjusted OR=1.48, 95% CI=1.06-2.07, P=0.020; TCA: adjusted OR=2.12, 95% CI=1.22-3.69, P=0.008).

Conclusion

Our findings suggested that miR-100 rs1834306 A>G polymorphism was associated with increased HSCR susceptibility in southern Chinese children. Furthermore, miR-100 rs1834306 GG genotype had a greater genetic pathopoiesis in severe HSCR.

miR-618 rs2682818 C>A polymorphism decreases Hirschsprung disease risk in Chinese children

MicroRNAs (miRNAs) are endogenous non-coding small RNAs that play an important role in the development of many malignant tumors. In addition, recent studies have reported that single nucleotide polymorphisms (SNPs) located in the miRNA functional region was inextricably linked to tumor susceptibility. In the present study, we investigated the susceptibility between miR-618 rs2682818 C>A and Hirschsprung disease (HSCR) in the Southern Chinese population (1470 patients and 1473 controls). Odds ratios (ORs) and 95% confidence intervals (CIs) were used for estimating the strength of interrelation between them. We found that the CA/AA genotypes of miR-618 rs2682818 were associated with a decreased risk of HSCR when compared with the CC genotype (OR = 0.84, 95% CI = 0.72–0.99, P=0.032). Based on the stratified analysis of HSCR subtypes, the rs2682818 CA/AA genotypes were able to significantly lessen the risk of HSCR compared with CC genotype in patients with long-segment HSCR (adjusted OR = 0.70, 95% CI = 0.52–0.93, P=0.013). In conclusion, our results indicated that the miR-618 rs2682818 C>A polymorphism was associated with a reduced risk of HSCR in Chinese children, especially in patients with long-segment HSCR (L-HSCR) subtype.

Pleiotropic effect of common PHOX2B variants in Hirschsprung disease and neuroblastoma

Hirschsprung disease (HSCR) is a heterogeneous congenital disorder that affects the enteric nervous system, while neuroblastoma is an embryonal tumor of the sympathetic nervous system. Familial cases of both HSCR and neuroblastoma appear to be functionally linked to PHOX2B, which plays a key role in the development of neural crest derivatives. However, the association between common PHOX2B variants and disease risk is contested. Additionally, large-scale examination for pleiotropy or shared genetic susceptibility in sporadic HSCR and neuroblastoma cases lacks theoretical support. Here, we report the first examination of PHOX2B in 1470 HSCR and 469 neuroblastoma patients with matched healthy controls. The PHOX2B rs28647582 polymorphism was found to be associated with HSCR (P = 2.21E-03, OR = 1.26), and each subtype of the ailment (3.22E-03 ≤ P ≤ 0.43, 1.11 ≤ OR ≤ 2.32). The association between rs28647582 and NB risk was consistent with HSCR in a recessive model, though the P value was marginal (P = 0.06). These new genetic findings indicate the potential pleiotropic effects of PHOX2B in both HSCR and neuroblastoma, which could guide the development of therapeutic targets for the treatment of related neurodevelopmental disorders.

Association of NRG1 and AUTS2 genetic polymorphisms with Hirschsprung disease in a South Chinese population

Hirschsprung disease (HSCR) is a genetic disorder characterized by the absence of enteric ganglia. There are more than 15 genes identified as contributed to HSCR by family-based or population-based approaches. However, these findings were not fulfilled to explain the heritability of most sporadic cases. In this study, using 1470 HSCR and 1473 control subjects in South Chinese population, we replicated two variants in NRG1 (rs16879552, P = 1.05E-04 and rs7835688, P = 1.19E-07), and further clarified the two replicated SNPs were more essential for patients with short-segment aganglionosis (SHSCR) (P = 2.37E-05). We also tried to replicate the most prominent signal (rs7785360) in AUTS2, which was a potential susceptibility gene with HSCR. In our results, in terms of individual association, marginal effect was observed to affect the HSCR patients following recessive model (P = 0.089). Noteworthy, significant intergenic synergistic effect between rs16879552 (NRG1) and rs7785360 (AUTS2) was identified through cross-validation by logistic regression (P = 2.45E-03, OR = 1.53) and multifactor dimensionality reduction (MDR, P < 0.0001, OR = 1.77). Significant correlation was observed between expression of these two genes in the normal segments of the colons (P = 0.018), together with differential expression of these genes between aganglionic colonic segments and normal colonic segments of the HSCR patients (P value for AUTS2 <0.0001, P value for NRG1 = 0.0243). Although functional evaluation is required, we supply new evidence for the NRG1 to HSCR and raised up a new susceptibility gene AUTS2 to a specific symptom for the disease.