Association of expression of DRD2 rs1800497 polymorphism with migraine risk in Han Chinese individuals

Clinical implications of genetic polymorphisms in blepharospasm

The possible genetic variants associated with blepharospasm (BSP) and facial dystonia have been investigated. Although genetic variants associated with BSP have been extensively studied, the contribution of single-nucleotide polymorphisms towards this condition remains poorly understood. In addition, the etiology of BSP remains to be fully elucidated. Therefore, the present study aimed to assess the role of polymorphisms in the torsin 1A (TOR1A), dopamine receptor D (DRD)2 and DRD5 genes in South Korean patients with BSP. Furthermore, the role of genetic variants of these three aforementioned genes was investigated. A prospective case-control study was established, where 56 patients with BSP and 115 healthy controls were recruited at the Department of Ophthalmology of CHA Bundang Medical Center (Seongnam, South Korea) using single nucleotide polymorphisms analysis by real-time PCR. The TOR1A rs1182CC/DRD5 rs6283TC genotype combination was found to be associated with decreased BSP risk [adjusted odds ratio (AOR), 0.288; P=0.013]. DRD5 rs6283 was observed to be associated with the periocular type of BSP in the co-dominant (for the TC genotype; AOR, 0.370; P=0.029) and dominant models (AOR, 0.406; P=0.029). The recessive model of TOR1A rs1801968 (AOR, 0.245; P=0.030), and the recessive (AOR, 0.245; P=0.029) and over-dominant models (AOR, 2.437; P=0.019) of DRD2 rs1800497 were found to be associated with superior responses to botulinum neurotoxin A (BoNT) treatment. By contrast, dominant (AOR, 0.205; P=0.034) and additive (AOR, 0.227; P=0.030) models of DRD5 rs6283 were associated with poor responses to BoNT treatment. To conclude, these results suggested that DRD2 rs1800497 can confer genetic susceptibility to BSP responses to BoNT treatment, whereas the TOR1A rs1182CC/DRD5 rs6283TC genotype combination appeared to contribute to the association with BoNT efficacy in BSP.

Genetic polymorphisms are involved in oral health-related quality of life in skeletal class III patients submitted to orthognathic surgery

OBJECTIVE

This study aimed to evaluate whether sex and genetic polymorphisms impact the oral health-related quality of life (OHRQoL) preoperatively and the difference between preoperative and postoperative OHRQoL in skeletal Class III patients submitted to orthognathic surgery.

MATERIALS AND METHODS

This longitudinal study consisted of ninety-nine patients with skeletal Class III malocclusion who required orthognathic surgery. The Oral Health Impact Profile-14 (OHIP-14) is a questionnaire used to assess the OHRQoL with a 5-point Likert-type scale, covering seven domains related to physical and psychosocial factors. The questionnaire was applied in the preoperative and postoperative periods, and the difference scores were calculated to assess the OHRQoL after orthognathic surgery. The DNA was extracted from oral mucosa cells to evaluate genetic polymorphisms in ANKK1, DRD2, ESR1, and ESR2 through real-time PCR.

RESULTS

There was an improvement in all OHRQoL domains following orthognathic surgery (p < 0.05). In the preoperative evaluation, women presented worse OHRQoL (p < 0.05) than men. There was no statistical difference between sex and the OHRQoL after surgery (p > 0.05). When evaluating the polymorphisms and preoperative OHIP-14 scores, CT genotype patients for rs1800497 (ANKK1) had a worse perception of the physical pain domain than CC genotype (p = 0.026), and CC genotype patients for rs1256049 (ESR2) had a worse perception of the functional limitation domain than CT genotype (p = 0.002). In the analysis between polymorphisms and postoperative and preoperative difference scores, CT genotype patients for rs1256049 (ESR2) had a greater improvement in the perception of the physical pain domain than the CC genotype (p = 0.031). In rs6275 and rs6276 (DRD2), patients with the CC genotype worsened the perception of the functional limitation domain than the TT genotype (p = 0.045), and AA genotype patients worsened the perception of the functional limitation domain than GG genotype (p = 0.048) after surgery, respectively. In addition, patients with the CT genotype for rs1800497 (ANKK1) had a greater improvement of OHRQoL perception in the total scale than the TT genotype (p = 0.018), and CT genotype patients had a greater improvement in the perception of function limitation domain than TT genotype (p = 0.017).

CONCLUSION

Women have a worse perception of OHRQoL in the preoperative period of orthognathic surgery. Furthermore, polymorphisms in the ANKK1, DRD2, and ESR2 genes could be involved with OHRQoL in the preoperative period and following orthognathic surgery.

CLINICAL RELEVANCE

The knowledge of the genetic background concerning OHRQoL in skeletal class III patients would aid in clinical practice to screen for associated genetic factors and prevent OHRQoL deterioration, especially after orthognathic surgery, considering that patients' genetic profiles would soon be available.

PACAP Induces Light Aversion in Mice by an Inheritable Mechanism Independent of CGRP

The neuropeptides CGRP (calcitonin gene-related peptide) and PACAP (pituitary adenylate cyclase-activating polypeptide) have emerged as mediators of migraine, yet the potential overlap of their mechanisms remains unknown. Infusion of PACAP, like CGRP, can cause migraine in people, and both peptides share similar vasodilatory and nociceptive functions. In this study, we have used light aversion in mice as a surrogate for migraine-like photophobia to compare CGRP and PACAP and ask whether CGRP or PACAP actions were dependent on each other. Similar to CGRP, PACAP induced light aversion in outbred CD-1 mice. The light aversion was accompanied by increased resting in the dark, but not anxiety in a light-independent open field assay. Unexpectedly, about one-third of the CD-1 mice did not respond to PACAP, which was not seen with CGRP. The responder and nonresponder phenotypes were stable, inheritable, and not sex linked, although there was a trend for greater responses among male mice. RNA-sequencing analysis of trigeminal ganglia yielded hierarchical clustering of responder and nonresponder mice and revealed a number of candidate genes, including greater expression of the Trpc5 and Kcnk12 ion channels and glycoprotein hormones and receptors in a subset of male responder mice. Importantly, an anti-PACAP monoclonal antibody could block PACAP-induced light aversion but not CGRP-induced light aversion. Conversely, an anti-CGRP antibody could not block PACAP-induced light aversion. Thus, we propose that CGRP and PACAP act by independent convergent pathways that cause a migraine-like symptom in mice.SIGNIFICANCE STATEMENT The relationship between the neuropeptides CGRP (calcitonin gene-related peptide) and PACAP (pituitary adenylate cyclase-activating polypeptide) in migraine is relevant given that both peptides can induce migraine in people, yet to date only drugs that target CGRP are available. Using an outbred strain of mice, we were able to show that most, but not all, mice respond to PACAP in a preclinical photophobia assay. Our finding that CGRP and PACAP monoclonal antibodies do not cross-inhibit the other peptide indicates that CGRP and PACAP actions are independent and suggests that PACAP-targeted drugs may be effective in patients who do not respond to CGRP-based therapeutics.

A Comprehensive Review on the Role of Genetic Factors in the Pathogenesis of Migraine

Migraine is a common neurovascular condition. This disorder has a complex genetic background. Several single-nucleotide polymorphisms (SNPs) or mutations within genes regulating glutamatergic neurotransmission, cortical excitability, ion channels, and solute carriers have been associated with polygenic and monogenic forms of migraine. SNPs within ACE, DBH, TRPM8, COMT, GABRQ, CALCA, TRPV1, and other genes have been reported to affect the risk of migraine or the associated clinical parameters. The distribution of some HLA alleles within the HLA-DRB1, HLA-DR2, HLA-B, and HLA-C regions have also been found to differ between migraineurs and healthy subjects. In addition, certain mitochondrial DNA changes and polymorphisms in this region have been shown to increase the risk of migraine. A few functional studies have investigated the molecular mechanisms contributing to these genetic factors in the development of migraine. Here we review studies evaluating the role of genetic polymorphisms and mRNA/miRNA dysregulation in migraine.

Dopamine receptor D2 and ankyrin repeat domain containing one in temporomandibular disorder of adolescents

BACKGROUND

Temporomandibular disorder (TMD) is a multifactorial condition that combines environmental and genetic factors and its prevalence increases during adolescence.

AIM

To investigate the association between TMD and genetic polymorphisms in the DRD2 and ANKK1 in a population of Brazilian adolescents.

DESIGN

The TMD group included adolescents diagnosed with any of the following TMD subgroups according to the RDC/TMD criteria: myofascial pain, arthralgia and disc displacement and painful TMD. Genomic DNA for molecular analysis was extracted from buccal cells, and genetic polymorphism rs6275 in DRD2 and rs1800497 in ANKK1 were genotyped by real-time polymerase chain reactions using the TaqMan assay. Data were analysed using the Epi Info 3.5.7 and Stata software, with significance level of 0.05.

RESULTS

Two hundred fifty-one individuals were included in this study, 148 subjects presented TMD. For disc displacement, the genetic polymorphisms rs6275 was associated in a recessive model (P = 0.04), whereas the rs6276 and rs1800497 presented only a borderline association in a recessive and dominant models, respectively (P = 0.07 and P = 0.06).

CONCLUSION

The genetic polymorphism rs6275 in DRD2 was associated with disc displacement in Brazilian adolescents.

Update on the pharmacogenomics of pain management

Pharmacogenomics is the study of genetic variants that impact drug effects through changes in a drug’s pharmacokinetics and pharmacodynamics. Pharmacogenomics is being integrated into clinical pain management practice because variants in individual genes can be predictive of how a patient may respond to a drug treatment. Pain is subjective and is considered challenging to treat. Furthermore, pain patients do not respond to treatments in the same way, which makes it hard to issue a consistent treatment regimen for all pain conditions. Pharmacogenomics would bring consistency to the subjective nature of pain and could revolutionize the field of pain management by providing personalized medical care tailored to each patient based on their gene variants. Additionally, pharmacogenomics offers a solution to the opioid crisis by identifying potentially opioid-vulnerable patients who could be recommended a nonopioid treatment for their pain condition. The integration of pharmacogenomics into clinical practice creates better and safer healthcare practices for patients. In this article, we provide a comprehensive history of pharmacogenomics and pain management, and focus on up to date information on the pharmacogenomics of pain management, describing genes involved in pain, genes that may reduce or guard against pain and discuss specific pain management drugs and their genetic correlations.