Increased major salivary gland secretion in familial dysautonomia

Familial dysautonomia (FD), an autosomal recessive peripheral nervous system disorder, affects almost exclusively children of Jewish Ashkenazi origin and causes profound generalized autonomic dysfunction. Excessive drooling is frequent and is traditionally attributed to swallowing difficulties. Although true hypersalivation has been postulated, no quantitative assessment of the salivary secretion rate has yet been reported. The authors determined this rate in 13 children with FD and 28 healthy controls. Resting parotid, submandibular/sublingual and unstimulated whole salivary secretion rates were significantly elevated in children with FD. The known relation of salivary function with age was found in controls only. This apparently major contribution of salivary hyperfunction to excessive drooling in FD may be attributable to salivary gland denervation supersensitivity, as this mechanism is present in the cardiovascular system and the pupil in FD.