A somatic GNA11 mutation is associated with extremity capillary malformation and overgrowth

Abstract

Background: Capillary malformation is a cutaneous vascular anomaly that is present at birth, darkens over time, and can cause overgrowth of tissues beneath the stain. The lesion is caused by a somatic activating mutation in GNAQ. In a previous study, we were unable to identify a GNAQ mutation in patients with a capillary malformation involving an overgrown lower extremity. We hypothesized that mutations in GNA11 or GNA14, genes closely related to GNAQ, also may cause capillary malformations.

Methods: Human capillary malformation tissue obtained from 8 patients that had tested negative for GNAQ mutations were studied. Lesions involved an extremity (n = 7) or trunk (n = 1). Droplet digital PCR (ddPCR) was used to detect GNA11 or GNA14 mutant cells (p.Arg183) in the specimens. Single molecule molecular inversion probe sequencing (smMIP-seq) was performed to search for other mutations in GNA11. Mutations were validated by subcloning and sequencing amplimers.

Results: We found a somatic GNA11 missense mutation (c.547C > T; p.Arg183Cys) in 3 patients with a diffuse capillary malformation of an extremity. Mutant allelic frequencies ranged from 0.3 to 5.0%. GNA11 or GNA14 mutations were not found in 5 affected tissues or in unaffected tissues (white blood cell DNA).

Conculsions: GNA11 mutations are associated with extremity capillary malformations causing overgrowth. Pharmacotherapy that affects GNA11 signaling may prevent the progression of capillary malformations.

Keywords: Capillary malformation; Extremity; GNA11; GNAQ; Vascular anomaly.

Figure 1

GNA11 mutation in Participant 5. (a) Photograph depicting the patient’s capillary malformation and hypertrophy of her left lower extremity. (b) Results from a ddPCR reaction displaying the presence of the GNA11 c.547C>T (p.ArgR183Cys) mutation with a mutant allele frequency of ~5%. (c) Sanger sequencing of PCR-amplimer-subclones showing (Top) a clone with the wild-type sequence and (Bottom) another with the mutation at position 547 having a T (red arrow) instead of a C (black arrow). (d) Integrative Genomic Viewer screen-shot depicting MIP-seq coverage at the site of the mutation (c.547C>T) with ~5% mutant allele frequency. 96x indicates the depth of coverage at position 547.