Related Experiment Video
Updated: Feb 11, 2026

Author Spotlight: Advancing the Detection of Low-Frequency Mutations in Cancer Tissues
Published on: August 23, 2024
Somatic GNAQ mutation in the forme fruste of Sturge-Weber syndrome
Michael S Hildebrand1, A Simon Harvey1, Stephen Malone1
1Department of Medicine (Austin Hospital) (M.S.H., J.A.D., Z.Y., L.M., I.E.S., S.F.B.), University of Melbourne, Heidelberg, Victoria, Australia; Murdoch Childrens Research Institute (M.S.H., A.S.H., G.G., K.P., P.J.L., R.J.L.), Parkville, Victoria, Australia; Department of Paediatrics (Royal Children's Hospital) (A.S.H., G.G., K.P., P.J.L., R.J.L., I.E.S.), Department of Pathology (H.D., R.K., A.D), and Department of Medicine (Royal Melbourne Hospital) (E.O., N.C.J.), University of Melbourne, Parkville, Victoria, Australia; Department of Neurology (A.S.H., R.J.L., I.E.S.) and Department of Neurosurgery (W.M.), Royal Children's Hospital, Parkville, Victoria, Australia; Department of Neurosciences (S.M., B.N.) and Neurosurgical Department (M.W.), Lady Cilento Children's Hospital, Brisbane, Queensland, Australia; Translational Genomics and Epigenomics Laboratory (H.D., A.D.), Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia; School of Cancer Medicine (H.D., A.D.), La Trobe University, Bundoora, Victoria, Australia; Anatomical Pathology (R.K.), Austin Health, Heidelberg, Victoria, Australia; Department of Neuroscience (N.C.J.), Central Clinical School, Monash University, Victoria, Australia; and Department of Neurology (N.C.J.), The Alfred Hospital, Melbourne, Victoria, Australia.
Objective:
To determine whether the GNAQ R183Q mutation is present in the forme fruste cases of Sturge-Weber syndrome (SWS) to establish a definitive molecular diagnosis.
Methods:
We used sensitive droplet digital PCR (ddPCR) to detect and quantify the GNAQ mutation in tissues from epilepsy surgery in 4 patients with leptomeningeal angiomatosis; none had ocular or cutaneous manifestations.
Results:
Low levels of the GNAQ mutation were detected in the brain tissue of all 4 cases-ranging from 0.42% to 7.1% frequency-but not in blood-derived DNA. Molecular evaluation confirmed the diagnosis in 1 case in which the radiologic and pathologic data were equivocal.
Conclusions:
We detected the mutation at low levels, consistent with mosaicism in the brain or skin (1.0%-18.1%) of classic cases. Our data confirm that the forme fruste is part of the spectrum of SWS, with the same molecular mechanism as the classic disease and that ddPCR is helpful where conventional diagnosis is uncertain.
More Related Videos
10:41Wild-type Blocking PCR Combined with Direct Sequencing as a Highly Sensitive Method for Detection of Low-Frequency Somatic Mutations
Published on: March 29, 2017
15:05Deciphering the Structural Effects of Activating EGFR Somatic Mutations with Molecular Dynamics Simulation
Published on: May 20, 2020
Related Concept Videos
Cancers Originate from Somatic Mutations in a Single Cell
Mutations
Mutations
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Viral Mutations
Mutation, Gene Flow, and Genetic Drift
Somatic Spinal Reflexes
One of the most well-known somatic spinal reflexes is the stretch reflex, which is activated by the sudden stretching of a muscle. This reflex involves the activation of specialized sensory receptors called muscle spindles, which are located in the muscle tissue and detect changes in the length and speed of muscle contractions. When a muscle is suddenly...