Cerebral amyloid angiopathy (CAA) is a chronic pathological condition characterized by progressive accumulation of amyloid protein in the wall of cerebral blood vessels, both leptomeningeal and cortical. That may result in the development of such conditions as microaneurysms, hemorrhagic, ischaemic brain injury and contribute to cognitive impairment. We herein report a case of Iowa-type hereditary cerebral amyloid angiopathy (CAA) mutation diagnosed with MS. The family of the reported patient had performed genetic testing due to the history of intracerebral hemorrhage. Sequence analysis of exon 17 of the APP gene showed the presence of the D694N g.275272 G > A (c.2080 G > A) mutation, which caused the substitution of aspartate for aspargine at position 694 of APP. Alike the discussed patient, this mutation has been found in other family members in an autosomal dominant pattern of inheritance. Contrary to the rest of the family, the reported patient has been diagnosed with multiple sclerosis based on McDonald criteria. Recent studies shed light on the possible link between the APP accumulation and MS progression. It has been indicated that amyloid can prove a vital role in neuroimmunology, whereas the accumulation of APP in the CNS has been suggested to be a potential biomarker for the progression of MS. Moreover, the amyloid positron-emission tomography (amyloid-PET) has been demonstrated to serve as a diagnostic tool for establishing the degree of demyelination and remyelination in MS. Even though, one swallow does not make a summer, this finding would be another step forward in the understanding of pathological processes underlying the pathogenesis of MS. Copyright © 2020 Elsevier B.V. All rights reserved.