Association of Postural Tachycardia Syndrome and Ehlers-Danlos Syndrome with Mast Cell Activation Disorders.

Mast cell activation disorders (MCADs) consist of episodic systemic symptoms due to mast cell mediator release. Diagnosis is based on clinical presentation and determination of high levels of tryptase or histamine. Ehlers-Danlos syndrome (EDS) and postural tachycardia syndrome (POTS) frequently coexist. It has been described that individuals with these syndromes can even present symptoms compatible to MCADs, which could represent a new specific phenotype. Preliminary genetic data suggest a role for tryptase in the pathogenesis of MCADs, EDS, and POTS association. Studies with larger samples evaluating clinics, genetics, and histopathology are required to define the real correlation between these 3 clinical entities.