Apraxia of Lid opening mimicking ptosis in compound heterozygosity for A467T and W748S POLG1 mutations

Patients harboring A467T and W748S POLGI mutations present with a broad variety of neurological phenotypes, including cerebellar ataxia, progressive external ophthalmoplegia (PEO), myoclonus, epilepsy, and peripheral neuropathy. With exception of ataxia and myoclonus, movement disorders are not typical features of POLGI associated disorders. We report on two affected siblings compound heterozygous for A467T and W748S mutations, one suffering from choreoathetosis and apraxia of lid opening due to focal eyelid dystonia that mimicked progression of ptosis, resulting in functional blindness. So far, focal dystonia has not been reported in POLGI mutation carriers, and should be considered when investigating patients with PEO and ptosis. Further studies on POLGI mutations in focal dystonia are warranted.