Hofmann, Jan BernhardJan BernhardHofmannGautschi, MatthiasMatthiasGautschi0000-0003-1358-1759Vossenkaul, AnjaAnjaVossenkaulBlanquet, MarisaMarisaBlanquetBrémovà-Ertl, TatianaTatianaBrémovà-Ertl2025-05-122025-05-122025-07https://boris-portal.unibe.ch/handle/20.500.12422/210774Introduction Alexander disease (AxD) is rare leukodystrophy caused by a mutation in the glial fibrillary acidic protein (GFAP) gene. Astrocyte dysfunction leads to myelinization disturbances and white matter damage, resulting in distinct neurological symptoms and neuroradiological findings.Case Report Our patient, a 46-year old male, showed typical symptoms of AxD, including myoclonus of the soft palate, nystagmus, and cerebellar ataxia, as well as typical radiological findings found in AxD. The results of a device-based vestibular examination, including a video head-impulse test, showed a bilaterally decreased gain of vestibulo-ocular reflex of all semicircular canals suggestive of a bilateral vestibulopathy (BVP), a novel aspect of AxD. Symptomatic treatment of cerebellar ataxia and BVP with 4-aminopyridine (4-AP) led to an improvement of several device-examined vestibular parameters, but without subjective improvements in balance.Conclusion This case report describes BVP in a patient suffering from AxD, a novel phenotype of the disease. In leukodystrophies, such as AxD, central vestibular symptoms should be assessed early on to evaluate the potential use of 4-AP.en4-aminopyridineAlexander diseaseBilateral vestibulopathyBrainstem atrophyVestibulo-ocular reflexarticle10.48620/879314032903810.1007/s00405-025-09416-7