Matrisome and Immune Pathways Contribute to Extreme Vascular Outcomes in Williams–Beuren Syndrome

Delong Liu, Charles J. Billington, Neelam Raja, Zoe C. Wong, Mark D. Levin, Wulfgang Resch, Camille Alba, Daniel N. Hupalo, Elisa Biamino, Maria Francesca Bedeschi, Maria Cristina Digilio, Gabriella Maria Squeo, Roberta Villa, Pheobe C.R. Parrish, Russell H. Knutsen, Sharon Osgood, Joy A. Freeman, Clifton L. Dalgard, Giuseppe Merla, Barbara R. PoberCarolyn B. Mervis, Amy E. Roberts, Colleen A. Morris, Lucy R. Osborne, Beth A. Kozel*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


BACKGROUND: Supravalvar aortic stenosis (SVAS) is a characteristic feature of Williams–Beuren syndrome (WBS). Its severity varies: ~20% of people with Williams–Beuren syndrome have SVAS requiring surgical intervention, whereas ~35% have no appreciable SVAS. The remaining individuals have SVAS of intermediate severity. Little is known about genetic modifiers that contribute to this variability. METHODS AND RESULTS: We performed genome sequencing on 473 individuals with Williams–Beuren syndrome and developed strategies for modifier discovery in this rare disease population. Approaches include extreme phenotyping and nonsynony-mous variant prioritization, followed by gene set enrichment and pathway-level association tests. We next used GTEx v8 and proteomic data sets to verify expression of candidate modifiers in relevant tissues. Finally, we evaluated overlap between the genes/pathways identified here and those ascertained through larger aortic disease/trait genome-wide association studies. We show that SVAS severity in Williams–Beuren syndrome is associated with increased frequency of common and rarer variants in matrisome and immune pathways. Two implicated matrisome genes (ACAN and LTBP4) were uniquely expressed in the aorta. Many genes in the identified pathways were previously reported in genome-wide association studies for aneurysm, bicuspid aortic valve, or aortic size. CONCLUSIONS: Smaller sample sizes in rare disease studies necessitate new approaches to detect modifiers. Our strategies identified variation in matrisome and immune pathways that are associated with SVAS severity. These findings suggest that, like other aortopathies, SVAS may be influenced by the balance of synthesis and degradation of matrisome proteins. Leveraging multiomic data and results from larger aorta-focused genome-wide association studies may accelerate modifier discovery for rare aortopathies like SVAS.

Original languageEnglish
Article numbere031377
JournalJournal of the American Heart Association
Issue number3
StatePublished - 6 Feb 2024
Externally publishedYes


  • Williams–Beuren syndrome
  • adaptive/innate immune system
  • elastin (ELN)
  • extreme phenotype
  • pathway analysis
  • supravalvar aortic stenosis


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