A genome-wide analysis in cluster headache points to neprilysin and PACAP receptor gene variants

Background

Cluster Headache (CH) is a severe primary headache, with a poorly understood pathophysiology. Complex genetic factors are likely to play a role in CH etiology; however, no confirmed gene associations have been identified. The aim of this study is to identify genetic variants influencing risk to CH and to explore the potential pathogenic mechanisms.

Methods

We have performed a genome-wide association study (GWAS) in a clinically well-defined cohort of 99 Italian patients with CH and in a control sample of 360 age-matched sigarette smoking healthy individuals, using the Infinium PsychArray (Illumina), which combines common highly-informative genome-wide tag SNPs and exonic SNPs. Genotype data were used to carry out a genome-wide single marker case-control association analysis using common SNPs, and a gene-based association analysis focussing on rare protein altering variants in 745 candidate genes with a putative role in CH.

Results

Although no single variant showed statistically significant association at the genome-wide threshold, we identified an interesting suggestive association (P = 9.1 × 10⁻⁶) with a common variant of the PACAP receptor gene (ADCYAP1R1). Furthermore, gene-based analysis provided significant evidence of association (P = 2.5 × 10⁻⁵) for a rare potentially damaging missense variant in the MME gene, encoding for the membrane metallo-endopeptidase neprilysin.

Conclusions

Our study represents the first genome-wide association study of common SNPs and rare exonic variants influencing risk for CH. The most interesting results implicate ADCYAP1R1 and MME gene variants in CH susceptibility and point to a role for genes involved in pain processing. These findings provide new insights into the pathogenesis of CH that need further investigation and replication in larger CH samples.

Electronic supplementary material

The online version of this article (doi:10.1186/s10194-016-0705-y) contains supplementary material, which is available to authorized users.

Hypertension in Patients with Heart Failure with Reduced Ejection Fraction

Hypertension (HTN) is a well-known health problem associated with considerable morbidity and mortality and it is an important risk factor for the development of heart failure (HF). These findings support the need for optimizing the antihypertensive strategies to prevent the progression to HF. Interestingly, the progression from HTN to HF, among other things, may be a consequence of inappropriate over-activation of the renin-angiotensin-aldosterone system (RAAS), sympathetic nervous system (SNS), and the natriuretic peptide system (NPS). In the present review, we will discuss the pathophysiological aspects of the progression from HTN to HF with reduced ejection fraction (HFrEF) and we will focus on the evolution of different pharmacological therapies which are reported to be effective in reducing BP and improving HF outcomes, paying particular attention to the recent trials that have demonstrated the efficacy of the combined therapy of RAAS blockade and Neprilysin (NEP) inhibitor in lowering BP and mediating several beneficial actions within cardiovascular tissues, such as avoiding the worsening of HF.