Diagnosis of DAO deficiency
For the diagnosis of the varied pathologies and syndromes caused by the DAO deficiency can be performed a study of molecular genetics of diamine oxidase activity (DAO) (AOC1-V) and/or an in vitro diagnostic test to measure the level of activity of the enzyme DAO in plasma.
Between the syndromes and diseases associated to the DAO deficiency are: migraine and other vascular headaches, gastrointestinal disorders, Irritable Bowel Syndrome (IBS) and Cyclic Vomiting Syndrome, atopic skin, dry skin, attention deficit and hyperactivity disorder (ADHD), fibromyalgia, chronic fatigue, generalized muscle pain and the effects of the acute intake of alcohol. When the trigger for these pathologies is the histaminic accumulation due to a DAO deficiency activity, the patient presents at least two or three of these symptoms.
Study of molecular genetics of diamine oxidase activity (DAO) (AOC1-V)
The genetic test consists of a non-invasive genetic study of the Diamine Oxidase activity. This is a test that performs a genotyping of high sensitivity of the most relevant genetic variants of the AOC1 gene (DAO) on the basis of a saliva sample (buccal mucosa).
It can be performed at home or in the pharmacy, is painless and non-invasive, results are received in 7 days and may indicate the likelihood of existence of gene variants associated with the DAO deficiency within the family, due to its inheritable nature.
Serum levels of expression of DAO presented great interindividual variation. For the gene that encodes the protein DAO/ABP1 (AOC1), have been described variants of type SNP (Single nucleotide variants), some of which are associated with reduced levels of DAO activity. In this test analyzes 3 of these allelic variants of AOC1:

Classification of variants according to the recommendations of the American College of Medical Genetics and Genomics according to nomenclature of HGVS.
Finally, the report of results specified the variants detected in the patient, as well as the phenotypic interpretation of DAO reduction of activity based on the results.
DAO Analytics®: in vitro diagnostic test to measure the level of activity of the enzyme diamine oxidase (DAO) in plasma
DAO ANALITICS® is an in vitro diagnostic test to measure the level of activity of the enzyme diamine oxidase (DAO) in plasma.
Their results determine a reduced DAO enzymatic activity when the values of HDU/ml (units of Histamine Degraded/minilitre of blood) are between 80-40 HDU/ml, or very low when they are under 40 HDU/ml.
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