Our findings indicate that ddPCR is an efficient method achieving a high diagnostic yield in our cohort when used prior to sequencing.
Key Findings
Results
Using ddPCR as a first-line test followed by sequencing for negative cases gave an overall diagnostic yield of 75% in a combined cohort of individuals with vascular anomalies.
The overall diagnostic yield was 104/138 (75%) when the 78 newly recruited individuals were combined with 60 individuals previously reported from the cohort.
The study examined feasibility of ddPCR as a primary diagnostic tool in a large cohort of individuals with VAs.
Most individuals with negative ddPCR results went on to high-depth gene panel or deep exome NGS, or Sanger sequencing.
Results
ddPCR alone detected a recurrent pathogenic variant in about half of the individuals tested.
Recurrent pathogenic variants were detected on ddPCR in 71 of 138 individuals (51%).
Lesional tissue was tested for up to 46 recurrent pathogenic variants across 16 genes associated with VAs.
Each specimen was assessed on a subset of assays chosen according to the individual's clinical phenotype.
Results
The ddPCR-detected variants were concentrated in a small number of genes, most commonly PIK3CA, TEK, GNAQ and MAP2K1.
PIK3CA variants were found in 28 individuals.
TEK variants were found in 18 individuals.
GNAQ variants were found in 12 individuals.
MAP2K1 variants were found in 7 individuals.
Results
Sequencing of ddPCR-negative cases identified pathogenic variants in a further 33 individuals.
These variants were identified on NGS (high-depth gene panel or deep exome) or Sanger sequencing.
71 ddPCR-positive plus 33 sequencing-positive cases account for the 104 diagnosed individuals.
Background
The study frames ddPCR as a rapid, sensitive, lower-cost alternative to NGS for recurrent mosaic variants, relevant to targeted precision therapies for VAs.
Targeted precision therapies are increasingly used in VAs, increasing the need for rapid, accurate and inexpensive genetic diagnosis.
Vascular anomalies are abnormalities of blood or lymphatic vessels that are often caused by genetic changes present in only some cells of the affected tissue. As targeted drug treatments become available, knowing the exact genetic cause quickly and affordably is increasingly important. This study tested whether a technique called droplet digital PCR (ddPCR), which looks for known, recurrent disease-causing variants in a sample of affected tissue, could be used as the first test before more extensive sequencing.
The researchers tested tissue from 138 people (78 new participants plus 60 reported earlier). ddPCR alone found a causative variant in 71 people (51%), most often in the genes PIK3CA, TEK, GNAQ and MAP2K1. Most people whose ddPCR was negative then had deeper sequencing, which found a further 33 causative variants, bringing the overall diagnostic yield to 104 of 138 people (75%).
This research suggests that ddPCR can be an efficient first step in genetic diagnosis of vascular anomalies, with sequencing reserved for those who test negative. The results come from a single cohort, so they show feasibility and diagnostic yield rather than a direct comparison with other testing strategies.
Lane T, Brown N, Green T, Garza D, de Silva M, Bennett M, et al.. (2026). Droplet digital PCR as a first-line detection tool in the genetic diagnosis of vascular anomalies.. Human molecular genetics. https://doi.org/10.1093/hmg/ddag109