see also:

• syncope / near syncope

• vasovagal syncope is a common and relatively benign cause of syncope which is the most common cause of syncope / near syncope in adolescents and young adults
• it should be differentiated from more serious causes such as prolonged QT syndrome and causes such as neurogenic orthostatic hypotension (nOH) and postural tachycardia syndrome

• there appears to be a familial component in patients who have vasovagal syncope
  • Barsheshet et al¹⁾, in studying LQTS genetics, found an 11-fold increased relative risk of syncope for subjects with the K897T polymorphism in KCNH2 and an 8-fold increased relative risk for subjects with the G38S polymorphism in KCNE1 in those who were genotype negative for LQTS.
  • Neurology 2013: Autosomal dominant vasovagal syncope: Clinical features and linkage to chromosome 15q26
  • homozygous people with gene variant for Zinc Finger Protein gene ZNF804A at chromosome 2q32.1 increases the risk of fainting by 30% ²⁾