Evidence of somatic mosaicism in Sturge-Weber syndrome

Sturge-Weber syndrome: an update on the relevant issues for neurosurgeons

PURPOSE

Sturge-Weber syndrome (SWS) is a neurocutaneous facomatosis characterized by facial and leptomeningeal angioma, glaucoma, seizures, and neurological disability. Therefore, a challenging multidisciplinary interaction is required for its management. The goal of this paper is to review the main aspects of SWS and to present an illustrative pediatric series.

METHODS

The pertinent literature has been analyzed, focused mainly on etiopathogenesis, pathology, clinical features, diagnostic tools, management, and outcome of the disease. Moreover, a series of 11 children operated on for refractory epilepsy between 2005 and 2015 (minimum follow-up 5 years, mean follow-up 9.6 years) is reported. The series consists of six boys and five girls with 6.5-month and 16.2-month mean age at seizure onset and at surgery, respectively. Seizures affected all children, followed by hemiparesis and psychomotor delay (81%), glaucoma (54%), and other neurological deficits (45%).

RESULTS

All children underwent hemispherectomy (anatomical in three cases, functional in two cases, hemispherotomy in six cases); one patient needed a redo hemispherotomy. Mortality was nil; disseminated intravascular coagulation and interstitial pneumonia occurred in one patient each; three children had subdural fluid collection. Eight patients (72%) are in the ILAE Class 1 (completely seizure and aura free), two in Class 2 (only auras, no seizure), and one in Class 3 (1-3 seizure days per year). AEDs discontinuation was possible in 73% of cases. The most important news from the literature concerned the pathogenesis (role of the mutation of the GNAQ gene in the abnormal SWS vasculogenesis), the clinical findings (the features and pathogenesis of the stroke-like episodes are being understood), the diagnostic tools (quantitative MRI and EEG), and both the medical (migraine, seizures) and surgical management (epilepsy). The epileptic outcome of SWS patients is very good (80% are seizure-free), if compared with other hemispheric syndromes. The quality of life is affected by the neurological and cognitive deficits.

CONCLUSIONS

SWS still is an etiological and clinical challenge. However, the improvements over the time are consistent. In particular, the neurosurgical treatment of refractory epilepsy provides very good results as long as the indication to treatment is correct.

Glaucoma in Patients with Eyes Close to Areas Affected by Port-wine Stain has Lateral and Gender Predilection

Background:

The location of facial port-wine stain (PWS) may be helpful for predicting some associated anomalies; high glaucoma incidence is found in patients with eyes close to PWS-affected areas (V1, ophthalmic branch area of the trigeminal nerve). This study aimed to investigate the characteristics of glaucoma in V1-affected PWS.

Methods:

A total of 569 patients with V1 area-affected PWS were reviewed in the study. The large series was based on the referral system between the Department of Plastic and Reconstructive Surgery and the Department of Ophthalmology. All patients were screened for glaucoma with assessments of intraocular pressure, cup-to-disc ratio, corneal diameter (only for infants), and axial length.

Results:

Of the 569 patients, 110 (19.3%) patients had glaucoma. Among the patients, 18.1% (76/420) had early-onset glaucoma (under 4-year-old group). In the 4 to 18-year-old age group, 29.3% (29/99) of the patients had glaucoma. Compared with right lateral and bilateral PWS, left-sided PWS had a lower risk of glaucoma in this study (odds ratio = 0.432 [95% confidence interval, 0.264–0.706], P = 0.01). The under 4-year-old group showed a slight predominance of males (61.8%) in glaucoma.

Conclusions:

High glaucoma incidence was observed in patients with eyes close to PWS. More attention should be paid to glaucoma screening for right lateral and bilateral PWS patients. The predominance of males in Sturge–Weber syndrome (SWS) early-onset glaucoma patients might be due to the limitation of the case number; however, it might also provide us a new clue of potential relationship between SWS and PCG.

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

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.

The somatic GNAQ mutation c.548G>A (p.R183Q) is consistently found in Sturge-Weber syndrome

Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterized by capillary malformation (port-wine stains), and choroidal and leptomeningeal vascular malformations. Previously, the recurrent somatic mutation c.548G>A (p.R183Q) in the G-α q gene (GNAQ) was identified as causative in SWS and non-syndromic port-wine stain patients using whole-genome sequencing. In this study, we investigated somatic mutations in GNAQ by next-generation sequencing. We first performed targeted amplicon sequencing of 15 blood-brain-paired samples in sporadic SWS and identified the recurrent somatic c.548G>A mutation in 80% of patients (12 of 15). The percentage of mutant alleles in brain tissues of these 12 patients ranged from 3.6 to 8.9%. We found no other somatic mutations in any of the seven GNAQ exons in the remaining three patients without c.548G>A. These findings suggest that the recurrent somatic GNAQ mutation c.548G>A is the major determinant genetic factor for SWS and imply that other mutated candidate gene(s) may exist in SWS.

Encephalotrigeminal Angiomatosis (Sturge-Weber Syndrome, Klippel-Trenaunay-Weber Syndrome): A Review

Sturge-Weber syndrome (SWS) (encephalotrigeminal angiomatosis) is a phakomatosis associated with port-wine stains of the face, seizures, mental retardation, and usually ipsilateral meningeal vascular malformations. The classic form affects leptomeninges, eyes, and face. Although the precise etiology and pathogenesis are unclear, the postulated defect is primary venous dysplasia with failure of the primordial embryonic venous plexus to regress. A spontaneous somatic mutation in fibroblast fibronectin gene expression in the vascular malformation may occur during embryonic development. Ocular involvement is characterized by conjunctival, episcleral, retinal, and choroidal vascular abnormalities. The vascular lesions have been inconsistently described as angiomas, hemangiomas, and vascular malformations. Based on the endothelial cellular activity, they can be considered vascular malformations (or port-wine stains), which never regress spontaneously. Congenital, developmental, and adult-onset glaucoma are often seen when the malformations involve the distribution of the first branch of the trigeminal nerve.Both mechanical and vascular causes have been proposed to account for the development of glaucoma. The mechanical theory is based on obstruction of aqueous outflow secondary to developmental anterior chamber angle abnormalities, and the vascular theory is based primarily on elevated episcleral venous pressure. Management of glaucoma in patients with SWS is often challenging and is aimed at controlling intraocular pressure and preventing progressive visual loss and blindness. It also carries an increased risk for surgical complications. This review summarizes the literature regarding the genetics, clinical features, and management of ocular complications of SWS with special focus on glaucoma.

Cell proliferation and oxidative stress pathways are modified in fibroblasts from Sturge-Weber syndrome patients

Sturge-Weber syndrome (SWS) is defined by vascular malformations of the face, eye and brain and an underlying somatic mutation has been hypothesized. We employed isobaric tags for relative and absolute quantification (iTRAQ-8plex)-based liquid chromatography interfaced with tandem mass spectrometry (LC-MS/MS) approach to identify differentially expressed proteins between port-wine-derived and normal skin-derived fibroblasts of four individuals with SWS. Proteins were identified that were significantly up- or down-regulated (i.e., ratios >1.2 or <0.8) in two or three pairs of samples (n = 31/972 quantified proteins) and their associated p values reported. Ingenuity pathway analysis (IPA) tool showed that the up-regulated proteins were associated with pathways that enhance cell proliferation; down-regulated proteins were associated with suppression of cell proliferation. The significant toxicologic list pathway in all four observations was oxidative stress mediated by Nrf2. This proteomics study highlights oxidative stress also consistent with a possible mutation in the RASA1 gene or pathway in SWS.

Updates and future horizons on the understanding, diagnosis, and treatment of Sturge-Weber syndrome brain involvement

AIM

To review recent developments in the understanding, diagnosis, and treatment of Sturge-Weber syndrome (SWS).

METHOD

Members of the Brain Vascular Malformation Consortium Sturge-Weber Syndrome National Workgroup contributed their expertise to review the literature and present promising directions for research.

RESULTS

The increasing number of reports dealing with SWS over the last decade reflects progress in the diagnosis and understanding of the neurological involvement. The proliferation of centers and advocacy groups to care for patients with SWS and to stimulate research has aided the development of new insights into the clinical manifestations and the pathophysiology of neurological progression, and the development of novel hypotheses to direct future research. Many key questions remain, but the tools and networks to answer them are being developed.

INTERPRETATION

This review summarizes important new knowledge and presents new research directions that are likely to provide further insights, earlier diagnosis, improved treatments, and possibly, prevention of this syndrome.

Leukocoria in a child with sturge-weber syndrome

A five-year-old girl with Sturge-Weber syndrome (SWS) presented with unilateral leukocoria. Imaging excluded retinoblastoma and revealed a choroidal hemangioma, a non-traumatic vitreous hemorrhage and a cataract. To the best of our knowledge, this is the first case report in the radiologic literature of these ophthalmologic findings presenting together and conditioning leukocoria in the setting of SWS. We discuss possible mechanisms and review the literature, emphasizing the role of neuroimaging in pediatric patients with SWS and ophthalmologic complaints.

Behavioral manifestations of sturge-weber syndrome: a case report

Sturge-Weber syndrome is a neurocutaneous syndrome that manifests with vascular malformations involving the brain, eye, and skin. We report the case of an elderly patient suffering from Sturge-Weber syndrome who presented with episodic "angry" slapping symptoms to a psychiatric facility. A detailed history, physical and mental-state examination, and elaborate neuropsychological, neuroimaging, and laboratory assessment were undertaken. Clinically, the "angry" slapping episodes were diagnosed as complex partial seizures that improved in frequency with an increase in the dose of the antiepileptic medication. We also have attempted to identify the pathophysiology of such behavioral episodes in Sturge-Weber syndrome. This case report underlines the need for detailed laboratory and neuroimaging work-up in the elderly presenting with atypical symptoms. It also emphasizes the need for identification of and differentiation between similar atypical presentations and appropriate management of resources by the medical staff.

The imaging of the cerebral venous sinuses

The cerebral venous sinuses in the past have been relatively neglected during radiological, neurological, and neurosurgical scientific discourse. However modern imaging and radiological approaches to treatment are demonstrating that far from being rare, the cerebral venous sinuses are involved in the pathogenesis of a protean list of ailments. During the review we hope to illustrate the imaging of diseases of the cerebral venous sinuses as demonstrated on multislice computer tomography and magnetic resonance imaging.

Port-wine vascular malformations and glaucoma risk in Sturge-Weber syndrome

PURPOSE

Treatment of the capillary vascular malformation (port-wine stain) in Sturge-Weber syndrome with the use of a laser is helpful cosmetically. However, concerns have been raised that laser obliteration of port-wine stains may result in ocular hypertension. The aim of this study was to review clinical features and management of ocular complications of SWS and assess the effects of dermatological laser treatment on the incidence of glaucoma or ocular hypertension.

METHODS

This retrospective cohort study was conducted in an institutional setting. All patients had involvement of the face. Patients who underwent skin laser to the port-wine vascular malformation were analyzed further. Ocular involvement, glaucoma, and skin laser treatment and the relationship to ocular hypertension/glaucoma were observed.

RESULTS

Forty-one Sturge-Weber syndrome patients with port-wine vascular malformation were analyzed. Glaucoma was observed in 24 patients (58.5%) at mean age of 2.9 years (range, 0.0-16.5). Of these, 18 (75.0%) were treated with medical therapy, and 10 (41.7%) required trabeculectomy, with 2 of these requiring Seton implant. Of the 41 patients, 28 (68.3%) underwent laser to face/forehead. Mean age of laser commencement was 5 years (range, 0.4-16.5). Thirteen did not undergo laser treatment. Fourteen of the 28 and 10 of the 13 developed ocular hypertension/glaucoma.

CONCLUSIONS

This retrospective review did not find evidence to suggest that laser treatment of port-wine vascular malformations causes glaucoma or that it can worsen a preexisting ocular hypertension or glaucoma. Statistical analysis was inconclusive.

Surgical and laser treatment of Sturge-Weber syndrome

Sturge-Weber syndrome (also called encephalofacial or encephalotrigeminal angiomatosis) is a rare neurocutaneous syndrome characterized by facial port-wine stains in the trigeminal nerve distribution area. An innovative treatment based on surgical and laser techniques of a patient affected with Sturge-Weber syndrome is reported. The aesthetic and functional results were satisfactory.

Hypomelanosis of Ito and Sturge-Weber syndrome without facial nevus: an association or a new syndrome?

Sturge-Weber syndrome without facial nevus is rare. Twenty-four cases were previously reported. Although hypomelanosis of Ito is a relatively common disorder, there was only one previous case in association with Sturge-Weber syndrome. We describe an 11-year-old boy with Sturge-Weber syndrome without facial nevus, coexistent with hypomelanosis of Ito.

Fibronectin: characterization of a somatic mutation in Sturge-Weber syndrome (SWS)

Sturge-Weber syndrome (SWS) is a rare, congenital neurocutaneous disorder with a leptomeningeal, facial trigeminal nerve dominative area and choroidal angioma. The cause of this disease remains unclear. Due to the occurrence of localized abnormality of blood vessel formation, somatic mutation has been put forward. Studies have indicated that fibronectin gene expressions in the SWS port-wine-derived fibroblasts are increased. Fibronectin is an important extracellular matrix molecule with key roles in regulating angiogenesis and vasculogenesis, in maintenance of the blood-brain barrier, blood vessel structure and function, as well as brain tissue responses to seizures. This is consistent with the presence of a hypothesized somatic mutation underlying SWS. In this study, we have proposed that fibronectin may be reflection of somatic mutation. Further research should be done to study the role of fibronectin in the pathogenesis of SWS. Understanding the pathophysiology of Sturge-Weber syndrome will help us to establish future neuroprotective strategies and novel treatment modalities.

The phakomatoses: dermatologic clues to neurologic anomalies

The phakomatoses of particular interest to neurologists including Sturge-Weber syndrome, neurofibromatosis type 1, neurofibromatosis type 2, Bannayan-Riley-Ruvalcaba syndrome, and Proteus syndrome are presented. The physical manifestations required for clinical diagnosis, the neurologic features, and recommendations for management are given. The molecular etiology and genetic aspects of these disorders are briefly discussed as well as future implications of on-going research.

Sturge-Weber syndrome: A case study

Sturge-Weber syndrome (SWS) is a rare, sporadic, progressive, congenital syndrome. In its complete trisymptomatic form, SWS is physically characterized by port-wine stains over the trigeminal area, leptomeningeal angiomas usually over the parieto-occipital region, and eye abnormalities. Clinical manifestation for infants with SWS depends on the affected organs, but can include seizures, mental retardation, and glaucoma. This article begins with a case presentation of an infant with SWS and then presents the etiology, embryology, pathophysiology, clinical presentation, management, and prognosis of SWS.

Advances in Sturge-Weber syndrome

PURPOSE OF REVIEW

Recent neuroimaging, clinical and molecular neuropathologic studies have provided new insights into the neurologic aspects of Sturge-Weber syndrome and are summarized here.

RECENT FINDINGS

Molecular studies suggest that abnormal brain blood vessel vasoactive and extracellular matrix molecule expression, as well as aberrant brain vascular innervation, contribute to the vascular malformation and its consequences. New magnetic resonance sequences may be useful for the early diagnosis of Sturge-Weber syndrome and perfusion magnetic resonance imaging, single photon emission computed tomography imaging, and positron emission tomography imaging studies are suggesting that decreased brain blood flow combined with altered hemodynamics during prolonged seizures may contribute to the neurologic declines in Sturge-Weber syndrome.

SUMMARY

Recent advances in our understanding of the neurologic issues offer promise for preventing brain injury in Sturge-Weber syndrome. More research is needed to translate advances in molecular research and neuroimaging advances into new treatment strategies for the disease.

Sturge-Weber syndrome

Sturge-Weber syndrome is a sporadic neurocutaneous disease characterized by facial port-wine stain, ocular abnormalities (glaucoma and choroidal hemangioma) and leptomeningeal angioma. Although the precise pathogenesis is unknown, available data regarding genetics, embryogenesis, and pathologic features are briefly reviewed. Clinical features vary from mild incomplete forms to full-blown disease with facial stain, seizures, and glaucoma. Frequencies of associated complications are reviewed. To plan treatment and further follow-up, diagnosis of glaucoma and intracranial involvement, even if asymptomatic, is fundamental in children at risk. Early neuroimaging features are important to recognize. Management of patients with Sturge-Weber syndrome is focused on treating associated neurologic and ocular abnormalities.

Pathophysiology of Sturge-Weber syndrome

Sturge-Weber syndrome is a neurocutaneous disorder classically presenting with a facial port-wine stain, vascular eye abnormalities, and an ipsilateral occipital leptomeningeal angioma. Children with Sturge-Weber syndrome often develop progressive neurologic problems. Data on the pathophysiology of Sturge-Weber syndrome are briefly reviewed. The embryologic, genetic, and pathologic considerations are discussed, as are theories regarding the mechanisms of the degenerative brain changes. Sturge-Weber syndrome likely results from an early embryologic malformation of vascular development affecting the development of the nearby skin, eye, and brain structures. Studies suggest that complex molecular interactions contribute to the abnormal development and function of blood vessels in Sturge-Weber syndrome. Neurologic deterioration in Sturge-Weber syndrome is likely secondary to impaired blood flow to the brain and is worsened by the presence of seizures. Insights from related areas are discussed, and future research studies are suggested.