Biotinidase deficiency should be considered in individuals thought to have multiple sclerosis and related disorders

Background: Multiple sclerosis is a disorder of the central and peripheral nervous system of young and old adults that is characterized by muscle, coordination and vision abnormalities. Multiple sclerosis is likely due to numerous causes. Methods: Recently, adolescents and adults with ophthalmological and or neurological findings have been diagnosed with biotinidase deficiency. These individuals have exhibited myelopathy, paresis and/or spastic diplegia/tetraplegia with or without optic neuropathy/vision loss. These older individuals with biotinidase deficiency were considered initially to have multiple sclerosis or similar disorders before they were determined to have biotinidase deficiency. Results: If a symptomatic individual with biotinidase deficiency is treated with biotin early enough, the symptoms markedly improve or completely resolve, but if treatment is delayed, the symptoms may be irreversible. Conclusion: Therefore, although biotinidase deficiency is rare relative to that of multiple sclerosis, the disorder should be included in the differential diagnosis of individuals thought to have multiple sclerosis or related disorders. Biotinidase deficiency should be considered in individuals thought to have multiple sclerosis or related disorders.