Prevalence of genetic diamine oxidase (DAO) deficiency in women with fibromyalgia in Spain

Abstract 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.