Isolated Cognitive Decline as the First Manifestation of CADASIL: a Case Report and Literature Review

Background: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare hereditary disease affecting small vessels in the brain caused by mutations in the NOTCH3 gene. It has a wide palette of clinical manifestations, usually starting with cognitive decline, migraine and headaches. Therefore, it is frequently misdiagnosed as a transitory ischaemic attack (TIA), ischaemic stroke, or migraine. As advances in genetic testing enable the detection of patients with CADASIL, its incidence is rising. However, CADASIL is still rarely diagnosed, especially in countries with scarce socio-economic resources in healthcare, such as genetic testing that is mandatory to diagnosticate CADASIL. However, it should be considered in everyday clinical practice as a differential diagnosis, especially in younger patients with positive family history. To our knowledge, there has not been a CADASIL case reported in Bosnia and Herzegovina. Objective: This case report aims to present rare confirmed case of CADASIL in a 56-year-old man that presented with rapid cognitive decline. Case presentation: A 56-year-old man was admitted to the Department of Neurology accompanied by his wife, who gave heteroanamnestic information. The patient works abroad and in the past month, during a telephone conversation, the wife noticed that the patient forgets what he has just said to her. The test results showed the presence of heterozygote mutation (c.401G>A) on the NOTCH3 gene, which confirmed the CADASIL diagnosis in this patient. He was further prescribed dual antiplatelet therapy and advised to do a follow-up exam in one month. Genetic advisory and testing of other family members was recommended, but it has not yet been conducted. He can still perform all activities of daily living. The importance of exome sequencing that enables the detection of a genetic mutations causing this rare disease is highlighted. Conclusion: Family members should also be advised to do genetic testing, as this enables the detection of CADASIL before the onset of symptoms. In addition, more aggressive preventive methods, life-style changes and symptomatic treatment can be included on-time, which will increase patient’s quality of life and decrease the development of various neurological complications.