Somatoform autonomic dysfunction or histamine intolerance due to genetic defect of diamine oxidase? From the phenomenological diagnosis of functional disorder to genetically determined clinical unit
Abstract
The case study describes young man suffering with gastrointestinal, skin and psychiatric symptoms. This symptoms were associated with histamine intolerance (HIT) that was induced by low serum activity of diamine oxidase (DAO ) and due to 3 mutations in AOC 1/ DAO gene.
DAO is the enzyme produced by the intestines that breaks down histamine. These mutations decrease effectivity of DAO and break down of histamine, which is toxic for body.
The symptoms of HIT have large symptomatic overlap with psychosomatic disorders or allergies. Our patient did fulfilled diagnostic criteria for mild depressive disorder.
The intensity of depressive symptoms measured by self-evaluation scales was clinically significant as well as intensity of anxiety symptoms. The patient fulfilled diagnostic criteria for Somatoform autonomic dysfunction - lower intestinal tract and irritable bowel syndrome before the proof of histamine intolerance (HIT).
It is possible that some patients with HIT who are not recognized by somatic doctors may enter psychiatric care with suspicion of psychosomatic disease, which is in fact of organic origin and can be specifically treated. Questions on HIT, and if suspected, then the identification of HIT biomarkers, should become part of the medical practice of so-called psychosomatic disorders that have symptomatic overlap with HIT.
The presented case report is an example how we would deconstruct the phenomenological diagnosis of functional disorder to genetically determined clinical unit.