Replication and meta-analyses nominate numerous eosinophilic esophagitis risk genes

BACKGROUND

Eosinophilic esophagitis (EoE) is an emerging, chronic, rare allergic disease associated with marked eosinophil accumulation in the esophagus. Previous genome-wide association studies have provided strong evidence for 3 genome-wide susceptibility loci.

OBJECTIVE

We sought to replicate known and suggestive EoE genetic risk loci and conduct a meta-analysis of previously reported data sets.

METHODS

An EoE-Custom single-nucleotide polymophism (SNP) Chip containing 956 candidate EoE risk single-nucleotide polymorphisms was used to genotype 627 cases and 365 controls. Statistical power was enhanced by adding 1959 external controls and performing meta-analyses with 2 independent EoE genome-wide association studies.

RESULTS

Meta-analysis identified replicated association and genome-wide significance at 6 loci: 2p23 (2 independent genetic effects) and 5q22, 10p14, 11q13, and 16p13. Seven additional loci were identified at suggestive significance (P < 10-6): 1q31, 5q23, 6q15, 6q21, 8p21, 17q12, and 22q13. From these risk loci, 13 protein-coding EoE candidate risk genes were expressed in a genotype-dependent manner. EoE risk genes were expressed in disease-relevant cell types, including esophageal epithelia, fibroblasts, and immune cells, with some expressed as a function of disease activity. The genetic risk burden of EoE-associated genetic variants was markedly larger in cases relative to controls (P < 10-38); individuals with the highest decile of genetic burden had greater than 12-fold risk of EoE compared with those within the lowest decile.

CONCLUSIONS

This study extends the genetic underpinnings of EoE, highlighting 13 genes whose genotype-dependent expression expands our etiologic understanding of EoE and provides a framework for a polygenic risk score to be validated in future studies.

Individuals affected by eosinophilic gastrointestinal disorders have complex unmet needs and frequently experience unique barriers to care

INTRODUCTION

Eosinophilic gastrointestinal disorders (EGIDs) are a rare but emerging healthcare problem. Patient advocacy groups (PAGs) have an important role in representing the EGID community, and serve as valuable research partners. By leveraging the partnership between medical researchers and PAGs, we examined the unmet needs and barriers to care perceived by individuals affected by EGIDs. Next, we examined if these varied between adult EGID patients and adult caregivers of children with EGID.

METHODS

Adult EGID patients and adult caregivers of children (<18 years) with EGIDs participated in this study. PAGs conducted focus groups comprised of individuals affected by EGIDs to identify domains and questions meaningful to the EGID community and this information was used to develop an online REDCap survey. The survey consisted of 58 questions across medical, healthcare, social, and emotional impact domains. It was distributed via the PAGs' web-based platforms. Demographic data, and responses to questions on a six-point Likert scale were collected and analyzed.

RESULTS

Of the 361 responses analyzed, 90 (25%) were from adult EGID patients and 271 (75%) were from adult caregivers. Of the applicable responses, in the medical domain only 19% of participants indicated that repeated endoscopies to monitor response to treatment was convenient. In the healthcare domain, 67% indicated that lack of insurance coverage for elemental formula was a barrier. In the social domain, only 5% of respondents reported adequate awareness of EGIDs in schools. In the emotional domain, 64% had experienced significant stress due to EGID related out-of-pocket costs. Multivariate logistic regression revealed that some of these responses varied between adult EGID patients and adult caregivers of children with EGID. The respondents indicated highest priority for improvement in the medical domain compared to other domains.

CONCLUSIONS

Individuals affected by EGIDs have a constellation of complex unmet needs and perceived barriers across medical, healthcare, social and emotional domains. Addressing unmet needs in the medical domain is relatively more important for the EGID community. Understanding unmet needs and barriers will likely help design improved patient-centered EGID care paradigms.

Correlations of inflammatory gene pathways, corticolimbic functional activities, and aggression in pediatric bipolar disorder: a preliminary study

The mechanisms underlying aggression in adolescents with bipolar disorder have been poorly understood. The present study has investigated the associations among TNF gene expressions, functional brain activations under the frustrative non-reward task, and aggression in adolescents with bipolar disorder. Baseline gene expressions and aggressive tendencies were measured with the RNA-sequencing and Brief Rating of Aggression by Children and Adolescents (BRACHA), respectively. Our results show that activity levels of left subgenual anterior cingulate gyrus (ACG), right amygdala, left Brodmann area 10 (orbitofrontal cortex), and right thalamus were inversely correlated with BRACHA scores and were activated with frustrative non-reward during the affective Posner Task. In addition, 11 TNF related gene expressions were significantly correlated with activation of amygdala or ACG during the affective Posner Task. Three TNF gene expressions were inversely correlated with BRACHA score while one TNF gene (TNFAIP3) expression was positively correlated with BRACHA score. Therefore, TNF-related inflammatory cytokine genes may play a role in neural activity associated with frustrative non-reward and aggressive behaviors in pediatric bipolar disorder.