Somatic PDGFRB activating variants in fusiform cerebral aneurysms

Karasozen, Yigit, Osbun, Joshua W, Parada, Carolina Angelica, Busald, Tina, Tatman, Philip, Gonzalez-Cuyar, Luis F, Hale, Christopher J, Alcantara, Diana, O'Driscoll, Mark, Dobyns, William B, Murray, Mitzi, Kim, Louis J, Byers, Peter, Dorschner, Michael O and Ferreira, Manuel (2019) Somatic PDGFRB activating variants in fusiform cerebral aneurysms. American Journal of Human Genetics, 104 (5). pp. 968-976. ISSN 1537-6605

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Abstract

The role of somatic genetic variants in the pathogenesis of intracranial-aneurysm formation is unknown. We identified a 23-year-old man with progressive, right-sided intracranial aneurysms, ipsilateral to an impressive cutaneous phenotype. The index individual underwent a series of genetic evaluations for known connective-tissue disorders, but the evaluations were unrevealing. Paired-sample exome sequencing between blood and fibroblasts derived from the diseased areas detected a single novel variant predicted to cause a p.Tyr562Cys (g.149505130T>C [GRCh37/hg19]; c.1685A>G) change within the platelet-derived growth factor receptor β gene (PDGFRB), a juxtamembrane-coding region. Variant-allele fractions ranged from 18.75% to 53.33% within histologically abnormal tissue, suggesting post-zygotic or somatic mosaicism. In an independent cohort of aneurysm specimens, we detected somatic-activating PDGFRB variants in the juxtamembrane domain or the kinase activation loop in 4/6 fusiform aneurysms (and 0/38 saccular aneurysms; Fisher's exact test, p < 0.001). PDGFRB-variant, but not wild-type, patient cells were found to have overactive auto-phosphorylation with downstream activation of ERK, SRC, and AKT. The expression of discovered variants demonstrated non-ligand-dependent auto-phosphorylation, responsive to the kinase inhibitor sunitinib. Somatic gain-of-function variants in PDGFRB are a novel mechanism in the pathophysiology of fusiform cerebral aneurysms and suggest a potential role for targeted therapy with kinase inhibitors.

Item Type: Article
Schools and Departments: School of Life Sciences > Sussex Centre for Genome Damage and Stability
Research Centres and Groups: Genome Damage and Stability Centre
Subjects: Q Science > QH Natural history > QH0301 Biology > QH0426 Genetics > QH0447 Genes. Alleles. Genome
Q Science > QH Natural history > QH0301 Biology > QH0426 Genetics > QH0460 Mutations
Q Science > QM Human anatomy > QM0531 Regional anatomy
Q Science > QP Physiology > QP0001 General Including influence of the environment
R Medicine > RB Pathology > RB024 Pathological anatomy and histology
R Medicine > RB Pathology > RB127 Manifestations of disease
Depositing User: Mark O'Driscoll
Date Deposited: 30 Apr 2019 12:09
Last Modified: 01 Jul 2019 13:01
URI: http://sro.sussex.ac.uk/id/eprint/83472

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