X-linked dystonia parkinsonism as a cause of isolated lingual dystonia (ILD)

Dystonia is a movement disorder characterized by sustained or intermittent muscle contractions that cause abnormal postures or repetitive movements. Isolated lingual dystonia (ILD) is a rare form of oromandibular dystonia, which affects only the tongue and accounts for about 4% of all dystonia cases. This report describes two Filipino males, aged 43 and 48, who developed ILD. The first patient is a 43-year-old male from Cebu, with no significant family history or roots from Panay Island, who was found to carry the X-linked dystonia parkinsonism (XDP)-causing variant highlighting a novel presentation of ILD linked to XDP. The second patient is a 48-year-old male from Roxas City, with a family history suggesting XDP, who presented with ILD initially and later developed tremor, limb dystonia, and bradykinesia. His diagnosis of XDP was confirmed by genetic testing. These cases highlight the importance of considering XDP in the differential diagnosis of ILD among Filipinos, regardless of geographic or familial predispositions. Genetic testing and follow-up examinations are crucial for managing ILD, as it may precede more generalized dystonic and parkinsonian symptoms associated with XDP. This study contributes to the limited literature on ILD and suggests new insights into the clinical variability of XDP.