Presence of fungiform papillae in classic dysautonomia.

Lack of fungiform papillae over the surface of the tongue is considered essential for the diagnosis of familial dysautonomia. We describe two cases with dysautonomia in which the diagnosis was delayed because numerous fungiform papillae were easily seen. Only a close inspection of the tongue with an ophthalmologic slit lamp revealed that each papilla was degenerated and atrophic. Lacking a clinical sine qua non or easily available diagnostic laboratory tests, fungiform papillae should be studied in detail to establish not only that their number is sufficient but also that their shape and structure are normal. The simple technique described enables confirmation of the diagnosis in children and newborns in whom familial dysautonomia is suspected.