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Objective Fibromyalgia (FM) patients have signs of relentless sympathetic hyperactivity associated with hyporeactivity to stress. Adrenergic receptors (ARs) are parts of the sympathetic nervous system that are fundamental for maintenance of homeostasis. We undertook this study to correlate α-AR and β-AR gene polymorphisms with the presence of FM and with different domains of the FM syndrome as measured by the Fibromyalgia Impact Questionnaire (FIQ). Methods We studied 78 Mexican FM patients and 48 age-matched controls as well as 78 Spanish FM patients and 71 controls. All subjects studied were women. Single-nucleotide polymorphisms (SNPs) of α1A-AR (rs574584, rs1383914, rs1048101, and rs573542), β2-AR (rs1042713 and rs1042714), and β3-AR (rs4994) were analyzed by 5′ exonuclease TaqMan polymerase chain reaction. Polymorphic haplotypes were constructed after linkage disequilibrium analysis. Results The β2-AR AC haplotype was a risk factor for the presence of FM. This haplotype had an increased frequency in Mexican patients compared with Mexican controls (42.1% versus 30.5%; P = 0.04). Similarly, 50.4% of Spanish patients had this haplotype compared with 40.0% of Spanish controls (P = 0.05). In Spanish patients, the α1A-AR SNP rs1383914 was associated with the presence of FM (P = 0.01), and the α1A-AR SNP rs1048101 was linked with FIQ disability (P = 0.02). Mexican patients with the rs574584 GG genotype presented the highest FIQ score compared with Mexican patients with other genotypes (P = 0.01), and in Mexicans SNP rs574584 was associated with FIQ morning stiffness (P = 0.04) and with FIQ tiredness upon awakening (P = 0.02). Conclusion AR gene polymorphisms are related to the risk of developing FM and are also linked to different domains of the FM syndrome.

Segawa disease is a rare dystonia due to autosomal dominant guanosine triphosphate cyclohydrolase I (adGTPCH) deficiency, affecting dopamine and serotonin biosynthesis. Recently, the clinical phenotype was expanded to include psychiatric manifestations, such as depression, anxiety, obsessive–compulsive disorder, and sleep disturbances. Although cognitive and neuropsychiatric symptoms may be attributable to dopamine deficiency in the prefrontal cortex and frontostriatal circuitry, intelligence is considered normal in Segawa disease. Our aim was to investigate neuropsychiatric symptoms and intelligence quotients (IQ) in a series of individuals with adGTPCH deficiency. The assessment included a structured clinical interview following the DSM-IV-TR’s guidelines, Beck’s Depression Inventory, the State-Trait Anxiety Inventory, the Maudsley Obsessive–Compulsive Questionnaire, the Barratt Impulsiveness Scale-11 (BIS-11), the Oviedo Sleep Questionnaire, the Pittsburgh Sleep Quality Index, and the Wechsler Adult Intelligence Scale-Third Edition. Equivalent tests were applied to pediatric patients as appropriate for their age group. Fourteen patients with adGTPCH deficiency were evaluated (seven adult and seven pediatric patients). Depression, anxiety, and obsessive–compulsive symptoms were not more common than expected in the general population. However, the seven adults showed impulsivity in the BIS-11; nine individuals had an IQ in the range of borderline intellectual functioning to mild mental retardation, and sleep disturbances were found in four individuals. We found no differences between these results and the motor impairment. In conclusion, our findings would suggest that cognitive impairment, and impulsivity in adults, may be associated with Segawa disease.

Autosomal dominant guanosine triphosphate cyclohydrolase I deficiency is an inborn error of neurotransmitter metabolism, with a prevalence of 0.5 per million, caused by mutations/deletions in the GCH1 gene. The finding of the mutation Q89X in the GCH1 gene in 23 patients from two pedigrees in an area inhabited by a population of 800,000 prompted us to consider that our cohort may have descended from a single founder. Twelve Q89X mutation-positive cases belonging to two families and 100 unrelated control subjects from the same geographical region were studied. Six microsatellite markers located near GCH1 were analyzed to validate a possible mutation-related founder haplotype. Haplotype analysis revealed two different haplotypes for six microsatellite markers that segregated with the Q89X mutation. A common haplotype in 10 out of 12 mutation carriers studied was identified. Two subjects carried a second haplotype, most probably because of a recombination event. However, at least 186 different haplotypes were established in the control subjects. In contrast with the frequencies of 83.3% and 16.7%, respectively, found for both mutation-segregating haplotypes, the frequency of none of the control haplotypes exceeded 1.5%. Dystonia was the most frequent symptom in our series, and parkinsonism was present in five patients. The large number of Q89X mutation carriers in our community is because of a founder effect. The same mutation in GCH1 causes a wide phenotypic spectrum of clinical variability occurring in this population of affected patients.

Autonomic dysfunction is frequent in patients with fibromyalgia (FM). Heart rate variability analyses have demonstrated signs of ongoing sympathetic hyperactivity. Catecholamines are sympathetic neurotransmitters. Catechol-O-methyltransferase (COMT), an enzyme, is the major catecholamine-clearing pathway. There are several single-nucleotide polymorphisms (SNPs) in the COMT gene associated with the different catecholamine-clearing abilities of the COMT enzyme. These SNPs are in linkage disequilibrium and segregate as 'haplotypes'. Healthy females with a particular COMT gene haplotype (ACCG) producing a defective enzyme are more sensitive to painful stimuli. The objective of our study was to define whether women with FM, from two different countries (Mexico and Spain), have the COMT gene haplotypes that have been previously associated with greater sensitivity to pain. All the individuals in the study were female. Fifty-seven Mexican patients and 78 Spanish patients were compared with their respective healthy control groups. All participants filled out the Fibromyalgia Impact Questionnaire (FIQ). Six COMT SNPs (rs2097903, rs6269, rs4633, rs4818, rs4680, and rs165599) were genotyped from peripheral blood DNA. In Spanish patients, there was a significant association between three SNPs (rs6269, rs4818, and rs4680) and the presence of FM when compared with healthy controls. Moreover, in Spanish patients with the 'high pain sensitivity' haplotype (ACCG), the disease, as assessed by the FIQ, was more severe. By contrast, Mexican patients displayed only a weak association between rs6269 and rs165599, and some FIQ subscales. In our group of Spanish patients, there was an association between FM and the COMT haplotype previously associated with high pain sensitivity. This association was not observed in Mexican patients. Studies with a larger sample size are needed in order to verify or amend these preliminary results.