Erratum: Corrigendum: Ultra–sensitive droplet digital PCR for detecting a low–prevalence somatic GNAQ mutation in Sturge–Weber syndrome

ObjectiveTo determine whether the GNAQ R183Q mutation is present in the forme fruste cases of Sturge-Weber syndrome (SWS) to establish a definitive molecular diagnosis.MethodsWe 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.ResultsLow 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.ConclusionsWe 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.

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Ultra–sensitive droplet digital PCR for detecting a low–prevalence somatic GNAQ mutation in Sturge–Weber syndrome

Scientific Reports ◽

10.1038/srep22985 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 29

Author(s):

Yuri Uchiyama ◽

Mitsuko Nakashima ◽

Satoshi Watanabe ◽

Masakazu Miyajima ◽

Masataka Taguri ◽

...

Keyword(s):

Detection Limit ◽

Nucleic Acid ◽

Somatic Mutation ◽

Digital Pcr ◽

Droplet Digital Pcr ◽

Blood Leukocytes ◽

Target Nucleic Acid ◽

Weber Syndrome ◽

Sturge Weber Syndrome ◽

Blood Leukocyte

Abstract Droplet digital PCR (ddPCR), a method for measuring target nucleic acid sequence quantity, is useful for determining somatic mutation rates using TaqMan probes. In this study, the detection limit of copy numbers of test DNA by ddPCR was determined based on Poisson distribution. Peptide nucleic acid (PNA), which strongly hybridises to target lesions, can inhibit target amplification by PCR. Therefore, by combination of PCR with PNA and ddPCR (PNA–ddPCR), the detection limit could be lowered. We reanalysed a somatic GNAQ mutation (c.548G > A) in patients with Sturge–Weber syndrome (SWS) using ddPCR and PNA–ddPCR. Importantly, among three patients previously found to be mutation negative by next–generation sequencing, two patients had the GNAQ mutation with a mutant allele frequency of less than 1%. Furthermore, we were able to find the same mutation in blood leukocyte or saliva DNA derived from four out of 40 SWS patients. Vascular anomalies and blood leukocytes originate from endothelial cells and haemangioblasts, respectively, which are both of mesodermal origin. Therefore, blood leukocytes may harbour the GNAQ mutation, depending on the time when the somatic mutation is acquired. These data suggest the possibility of diagnosis using blood DNA in some patients with SWS.

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Somatic GNAQ R183Q mutation is located within the sclera and episclera in patients with Sturge-Weber syndrome

British Journal of Ophthalmology ◽

10.1136/bjophthalmol-2020-317287 ◽

2021 ◽

pp. bjophthalmol-2020-317287

Author(s):

Yue Wu ◽

Cheng Peng ◽

Lulu Huang ◽

Li Xu ◽

Xuming Ding ◽

...

Keyword(s):

Endothelial Cells ◽

Blood Vessels ◽

Open Angle Glaucoma ◽

Anterior Segment ◽

Digital Pcr ◽

Secondary Glaucoma ◽

Congenital Glaucoma ◽

Open Angle ◽

Weber Syndrome ◽

Sturge Weber Syndrome

AimsTo determine the correspondence between GNAQ R183Q (c.548G＞A) mutation in abnormal scleral tissue of patients with Sturge-Weber syndrome (SWS) secondary glaucoma and explore the role of GNAQ R183Q in glaucoma pathogenesis.MethodsEpiscleral tissues were obtained from 8 patients: SWS secondary glaucoma (n=5) and primary congenital glaucoma (PCG, n=3). Scleral tissues were obtained from 7 patients: SWS secondary glaucoma (n=2), PCG (n=1) and juvenile open-angle glaucoma (n=4). GNAQ R183Q mutation was detected in scleral tissue by droplet digital PCR. Tissue sections from SWS were examined by immunohistochemistry to determine the expression of p-ERK.ResultsThe GNAQ R183Q mutation was present in 100% of the SWS abnormal sclera. Five cases were SWS patient-derived episcleral tissue, and the mutant allelic frequencies range from 6.9% to 12.5%. The other two were deep scleral tissues and the mutant frequencies were 1.5% and 5.3%. No mutations in GNAQ R183 codon were found in the sclera of PCG and juvenile open-angle glaucoma. Increased expression of p-ERK and p-JNK was detected in the endothelial cells of SWS abnormal scleral blood vessels.ConclusionsGNAQ R183Q occurred in all abnormal scleral tissue of SWS secondary glaucoma. Increased expression of p-ERK and p-JNK in endothelial cells of blood vessels was detected in the abnormal scleral tissue. This study suggests GNAQ R183Q may regulate episcleral vessels of patients with SWS through abnormal activation of ERK and JNK, providing new genetic evidence of pathogenesis of glaucoma in SWS, and the dysplasia of scleral tissue in anterior segment may be used as an early diagnostic method or treatment targets to prevent the development and progression of glaucoma in patients with SWS.

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