Submandibular and sublingual salivary gland function in familial dysautonomia

Objective. Drooling in familial dysautonomia (FD) has been attributed to denervation supersensitivity. The aim of this study was to investigate submandibular and sublingual (SM/SL) gland function in FD. Study design. SM/SL saliva was collected from 15 children with FD and from 31 healthy control subjects. The protein and electrolyte content and the salivary flow rate were determined in each subject. Results. Children with FD displayed significantly elevated outputs of chloride, potassium, calcium, phosphorous, magnesium, and total protein. Salivary flow rates were significantly increased. Phosphorous concentration was statistically low. These results imply SM/SL hyperfunction at the acinar and ductal levels. The concentration of lysozyme, the activity of amylase, and the output of both were similar in patients and control subjects. Conclusion. SM/SL gland hyperactivity is a newly described abnormality in FD. At the acinar level, this hyperactivity is expressed with increased fluid, electrolyte, and protein output, and at the ductal level, with increased ion secretion and absorption rate. These changes may be the result of ongoing parasympathetic denervation characteristic in FD.