Diamine oxidase (DAO) is an enzyme that metabolizes intestinal histamine. Single nucleotide polymorphisms (SNPs) of the Amine Oxidase Copper Containing 1 (AOC1) gene can lead to low enzymatic activity or functionality in histamine metabolism. This study aimed to determine the prevalence of DAO deficiency for four variants of the AOC1 gene, p.Thr16Met (rs10156191), p.Ser332Phe (rs1049742), p.His664Asp (rs1049793), and c.691G > T (rs2052129), in 98 Spanish women with fibromyalgia between the ages of 33 and 60 years, and compare the distribution of allelic and genotypic frequencies with those of European population samples in Hardy–Weinberg equilibrium extracted from the Allele Frequency Aggregator (ALFA) database. The patients’ DNA was extracted, and analyzed using SNPE Multiplex (Single Nucleotide Primer Extension). The prevalence of genetic DAO deficiency was 74.5% based on the four variants of the AOC1 gene. SNP deficits were found at frequencies of 53.1% for p.Thr16Met, 49% for c.691G > T, 48% for p.His664Asp, and 19.4% for p.Ser332Phe. The allele and genotypic frequencies of the women with fibromyalgia did not differ from the European population. Variants of the AOC1 gene that are associated with genetic DAO deficiency could serve as a disruptive biomarker in patients with fibromyalgia. This study was registered in ClinicalTrials.gov Identifier: NCT05389761.

Introduction: The amine oxidase copper-containing 1 (AOC1) gene encodes for the diamine oxidase (DAO) enzyme. DAO is an enzyme that catabolizes some molecules, including histamine, and is the degradative enzyme in the polyamine catabolic pathway that is active in intestinal mucosal cells. Variants of AOC1 are associated with reduced DAO activity, resulting in accumulation of high levels of histamine and causing a wide range of neurological, gastrointestinal, and epidermal disorders, which are present in people with fibromyalgia. This study aimed to evaluate the impact of four AOC1 gene variants, namely, rs10156191, rs1049742, rs1049793, and rs2052129, on fibromyalgia symptoms measured by the Fibromyalgia Impact Questionnaire (FIQ), such as sleep disorders, atopic dermatitis, migraine, gastrointestinal (GI) disorders, allergies, and intolerances, in adult women with fibromyalgia.Methods: The sample consisted of 100 unrelated women with fibromyalgia between 33 and 60 years of age (48.48 years ±7.35), whose were diagnosed by a rheumatologist based on symptoms such as pain, stiffness, and fatigue. Single-nucleotide polymorphisms (SNPs) of AOC1 were identified using oral mucosa samples collected following a standard hygiene protocol. DNA was extracted, and gene variants of interest were analyzed using multiplex single-nucleotide primer extension (SNPE). Clinical data were collected using the FIQ and a series of variables that quantified the intensity and frequency of the symptoms.Results: The minor allele frequencies of rs10156191, rs1049742, rs1049793, and rs2052129 were 31.5, 10, 32.5, and 27%, respectively. Each variant was found to be in Hardy–Weinberg equilibrium, but partial linkage disequilibrium between AOC1 SNPs is suspected. The results show that fibromyalgia symptoms measured using the FIQ tend to increase with the number of risk alleles and that the intensity of dry skin and low stool consistency may be associated with an increase in the number of these alleles.Conclusion: This study constitutes the first step in investigating associations between fibromyalgia symptoms and candidate variants of the AOC1 gene in DAO enzyme activity. Identification of reduced DAO activity may improve the quality of life and treatment of symptoms in fibromyalgia patients.

Diamine oxidase (DAO) is the enzyme responsible for the metabolism of intestinal histamine. Single nucleotide polymorphisms (SNPs) of the AOC1 gene are associated with low enzymatic activity or functionality in the metabolism of histamine. The objectives of the present study were to determine the prevalence of DAO deficiency for four variants of the AOC1 gene, p.Thr16Met (rs10156191), p.Ser332Phe (rs1049742), p.His664Asp (rs1049793) and c.691G > T (rs2052129) in Spanish women with fibromyalgia, as well as to compare the distribution of allelic and genotypic frequencies with European population samples in Hardy-Weinberg equilibrium (HWE) extracted from the ALFA (Allele Frequency Aggregator) database. The sample consisted of 98 Spanish women with fibromyalgia between 33 and 60 years old (48.5 years ± 7.5) DAO enzyme activity was determined by a sample of oral mucosa and a standard hygiene protocol was followed. The patients' DNA was extracted and the analysis of gene variants of interest was performed using SNPE Multiplex (Single Nucleotide Primer Extension). The prevalence of genetic DAO deficiency was 74.5% by the four variants of the AOC1 gene. The deficit for each SNP followed the following frequencies: p.Thr16Met (53.1%), c.691G > T (49%), p.His664Asp (48%) and p.Ser332Phe (19.4%). The allelic and genotypic prevalence of the variants had similar distributions of European population except for p.Ser332Phe. Variants of the AOC1 gene could be associated with genetic DAO deficiency and potential disruptive biomarker in fibromyalgia patients.

Diamine oxidase (DAO) is the enzyme responsible for the metabolism of intestinal histamine. Single nucleotide polymorphisms (SNPs) of the AOC1 gene are associated with low enzymatic activity or functionality in the metabolism of histamine. The objectives of the present study were to determine the prevalence of DAO deficiency for four variants of the AOC1 gene, p.Thr16Met (rs10156191), p.Ser332Phe (rs1049742), p.His664Asp (rs1049793) and c.691G>T (rs2052129) in Spanish women with fibromyalgia, as well as to compare the distribution of allelic and genotypic frequencies with European population samples in Hardy-Weinberg equilibrium (HWE) extracted from the ALFA (Allele Frequency Aggregator) database. The sample consisted of 98 Spanish women with fibromyalgia between 33 and 60 years old (48.5 years ± 7.5) DAO enzyme activity was determined by a sample of oral mucosa and a standard hygiene protocol was followed. The patients' DNA was extracted and the analysis of gene variants of interest was performed using SNPE Multiplex (Single Nucleotide Primer Extension). The prevalence of genetic DAO deficiency was 74.5% by the four variants of the AOC1 gene. The deficit for each SNP followed the following frequencies: p.Thr16Met (53.1%), c.691G>T (49%), p.His664Asp (48%) and p.Ser332Phe (19.4%). The allelic and genotypic prevalence of the variants had similar distributions of European population except for p.Ser332Phe. Variants of the AOC1gene could be associated with genetic DAO deficiency and potential disruptive biomarker in fibromyalgia patients. This study was registered in ClinicalTrials.gov Identifier: NCT05389761