Tongue Protrusion Dystonia in Pantothenate Kinase-Associated Neurodegeneration.

BACKGROUND: Tongue protrusion dystonia is an uncommon focal dystonia involving the lingual muscles. Causes of tongue protrusion dystonia include tardive dystonia, posthypoxic dystonia, neuroacanthocytosis, pantothenate kinase-associated neurodegeneration, and Lesch-Nyhan syndrome. METHOD: We summarize three children with pantothenate kinase-associated neurodegeneration and tongue protrusion dystonia. All three patients underwent careful neurological examination, brain magnetic resonance imaging, and genetic testing. RESULTS: Tongue protrusion dystonia was a prominent and disabling symptom in all three patients. Brain magnetic resonance imaging revealed a typical eye of the tiger sign in all patients. Two patients had the same genetic mutation (c.1168 A>T mutation, p.I390F). CONCLUSIONS: Tongue protrusion dystonia may be a clue to the underlying etiology of dystonia, including hereditary forms of dystonia. Among them, pantothenate kinase-associated neurodegeneration is an important cause, especially in children.