ABSTRACT NUMBER: ESOC2026A910 NOVEL C.4649T>A MISSENSE VARIANT IN MYLK GENE IN A CASE OF ACUTE TYPE A AORTIC AND CAROTID ARTERY DISSECTION COMPLICATED BY ACUTE ISCHEMIC STROKE

Abstract Background and aims Up to 30% of cases of acute type A aortic dissection (ATAAD) are associated with carotid artery dissection, a significant risk factor for acute ischemic stroke. Genetic testing is often performed to exclude the involvement of variants that can cause or predispose to this condition. We present the genetic study of a 58-year-old Italian woman affected by acute type A aortic dissection with right carotid artery dissection and subsequent acute ischemic stroke. Methods A Next Generation Sequence (NGS) panel of 25 genes involved in structural and functional mechanism of arterial wall was tested in the patient. Results Patient’s anamnesis included hypertension, active tobacco use and past alcohol abuse as vascular risk factors, while neither atraumatic fractures nor spontaneous dislocations except for congenital hip dislocation had ever occurred. Her 33-year-old daughter suffered from headache. No cases of arterial dissection were documented in other family members. Patient’s genetic study showed a heterozygous c.4649T>A p.(Ile1550Asn) missense variant in the protein kinase domain of MYLK gene, with a potential deleterious effect according to in silico models. This variant is rare, has never been previously described in literature and has therefore been classified of uncertain clinical significance (ACMG class 3). Conclusions This case highlights the possible pathogenic role of this novel missense MYLK variant in this case of ATAAD. We are currently monitoring first-grade relatives for any further clinical suggestion and screening them with aortic CT angiography potentially followed by genetic testing in order to better characterize the role of this variant. Conflict of interest Manuel Menabue: nothing to disclose Figure 1 - belongs to Results