Clinical Utility of Next-Generation Sequencing Panel Testing in the Evaluation of Arteriovenous Malformations

Abstract Arteriovenous malformations (AVMs) are vascular lesions in which an overgrowth of blood vessels of varying sizes develops with one or more direct connections between the arterial and venous circulation. AVMs are seen in sporadic and syndromic conditions that are caused by a variety of genomic alterations. Here, we performed a retrospective review of the cases sent for next-generation sequencing (NGS) analysis for diseases of somatic mosaicism (DoSM). Specimens from 54 patients with clinical indication of AVMs were submitted for the DoSM NGS panel between October 2013 and Dec 2021. DNA extraction and sequence analysis were performed on affected tissues, including fresh tissue, formalin-fixed paraffin-embedded tissue, fibroblast cultures, and buccal specimens. Single-nucleotide variants (SNVs) with variant allele fractions (VAFs) greater than 3% and small insertions and deletions (indels, <21 bp) were called using VarScan2, Genome Analysis Toolkit (GATK), and Pindel. Variants with VAFs between 1-3% were manually reviewed based on the sequencing data quality and the known clinical significance. 38/54 (69.1%) patients were females and 16/54 (30.9%) were males. Ages ranged from 1 month to 73 years (median age 17 years). Most of the patients were indicated with sporadic AVM (81%), although additional clinical indications were noticed, including unspecified congenital vascular malformation (9.1%), capillary malformation (5.5%), arteriovenous fistula, and AVM associated with capillary and lymphatic malformations (1.8% each). The biopsied lesion was most often located in the head (43.6%), followed by the limbs (30.9%), and unspecified areas of the body in the remaining 25.5%. Among the 54 cases, 37 (68.5%) cases had pathogenic and/or likely pathogenic (P/LP) variants identified, 2 cases (3.7%) had variants of unknown significance, and the remaining 15 cases (27.8%) had negative results. MAP2K1 variants were found in 12 samples, followed by KRAS (8), TEK (7), PTEN (5), BRAF (4), TSC2 (2), HRAS (2), RASA1 (2), and PDGFRB (1). Of note, four cases had two P/LP variants. Among the 37 positive cases, 32 cases had somatic alterations; the remaining 5 cases had at least one germline P/LP variant, including PTEN (4) and RASA1 (1). In summary, the diagnostic yield of cases with clinical indication of AVMs was 68.5% using our in-house DoSM NGS panel. This study demonstrates the clinical utility of the DoSM NGS panel testing in the evaluation of a cohort with clinical presentations of AVMs.