Mosaic Activating Mutations in GNA11 and GNAQ Are Associated with Phakomatosis Pigmentovascularis and Extensive Dermal Melanocytosis

Somatic GNA11/GNAQ variants in a cohort of Chinese children with phakomatosis pigmentovascularis

Importance

Postzygotic mutations in the GNAQ/GNA11 genes, which encode the G-protein nucleotide binding protein alpha subunits, have been identified in patients with phakomatosis pigmentovascularis (PPV). However, little is known about the Chinese population.

Objective

To identify pathogenic mutations in pediatric patients with PPV within the Chinese population.

Methods

We performed whole-exome sequencing (WES) using skin lesion tissues from pediatric patients diagnosed with PPV. Additionally, ultradeep-targeted sequencing was conducted to validate the somatic mutations. A genotype-phenotype correlation was analyzed by integrating data from previous reports with the findings of the present study.

Results

Thirteen patients were enrolled, all diagnosed with the cesioflammea type of PPV, except for one patient with an unclassifiable type. We identified somatic GNA11 c.547C>T (p.R183C) variant in seven patients and GNAQ c.548G>A (p.R183Q) in four patients, with low allelic fractions ranging from 2.1% to 8.6% through ultradeep sequencing. Besides, a GNAQ c.548G>A (p.R183Q) variant was detected through targeted sequencing in one of two patients who did not exhibit detectable variants via WES. The genotype-phenotype correlation analysis, involving 15 patients with a GNA11 variant and 10 with a GNAQ variant, revealed that facial capillary malformation (87% vs. 50%, P = 0.075) and ocular melanocytosis (80% vs. 40%, P = 0.087) appeared to be more frequent in patients with GNA11 mutation compared to those with GNAQ mutations. All four patients diagnosed with cesiomarmorata type or overlapping cesioflammea and cesiomarmorata type PPV carried the GNA11 variant.

Interpretation

Our study demonstrated that the majority of PPV patients in the Chinese population carried a postzygotic variant of GNAQ/GNA11, thus further confirming the pathogenic role of GNAQ/GNA11 mosaicism in the development of PPV cesioflammea type.

Photodynamic therapy for the treatment of port-wine stains in phakomatosis pigmentovascularis

BACKGROUND

Phakomatosis pigmentovascularis (PPV) is a rare congenital syndrome. Only a few studies have reported the treatment of PPV, including a case using photodynamic therapy (PDT) to treat PPV-associated port-wine stains (PWS).

OBJECTIVE

To investigating the efficacy and adverse effects of hemoporfin-PDT in PPV-associated PWS.

METHODS

The efficacy and adverse effects in patients with PPV who underwent two sessions of hemoporfin-PDT from January 2019 to December 2022 were retrospectively analyzed.

RESULTS

Twenty patients were included (13 females, 7 males, age range: 2-31 years; mean: 8.20 ± 8.92 years). Two, nine, seven, and two patients had PPV types Ia, IIa, IIb, and IIIa, respectively. After two treatments, the visual evaluation indicated the color of the PWS in 4, 5, 6, and 5 patients showed poor, fair, good, and excellent improvements, respectively. The combined good and excellent improvement rates in patients with PWS and pigmentary nevus overlapping in the same treatment area and in patients with PWS in the treatment areas only were 33.3% versus 87.5%, respectively, and were significantly different (p = 0.02). Minor side effects, such as edema, scabbing, hyperpigmentation, and blistering, were observed in some patients after PDT.

CONCLUSION

Hemoporfin-PDT is an effective treatment for PPV-associated PWS. Patients with PWS and pigmentary nevus overlapping in the same treatment area showed poorer efficacy than patients with PWS in the treatment areas only.

Capillary malformations

Capillary malformation (CM), or port wine birthmark, is a cutaneous congenital vascular anomaly that occurs in 0.1%-2% of newborns. Patients with a CM localized on the forehead have an increased risk of developing a neurocutaneous disorder called encephalotrigeminal angiomatosis or Sturge-Weber syndrome (SWS), with complications including seizure, developmental delay, glaucoma, and vision loss. In 2013, a groundbreaking study revealed causative activating somatic mutations in the gene (GNAQ) encoding guanine nucleotide-binding protein Q subunit α (Gαq) in CM and SWS patient tissues. In this Review, we discuss the disease phenotype, the causative GNAQ mutations, and their cellular origin. We also present the endothelial Gαq-related signaling pathways, the current animal models to study CM and its complications, and future options for therapeutic treatment. Further work remains to fully elucidate the cellular and molecular mechanisms underlying the formation and maintenance of the abnormal vessels.

GNAQ/GNA11 Mosaicism Causes Aberrant Calcium Signaling Susceptible to Targeted Therapeutics

Mosaic variants in genes GNAQ or GNA11 lead to a spectrum of vascular and pigmentary diseases including Sturge-Weber syndrome, in which progressive postnatal neurological deterioration led us to seek biologically targeted therapeutics. Using two cellular models, we find that disease-causing GNAQ/11 variants hyperactivate constitutive and G-protein coupled receptor ligand-induced intracellular calcium signaling in endothelial cells. We go on to show that the aberrant ligand-activated intracellular calcium signal is fueled by extracellular calcium influx through calcium-release-activated channels. Treatment with targeted small interfering RNAs designed to silence the variant allele preferentially corrects both the constitutive and ligand-activated calcium signaling, whereas treatment with a calcium-release-activated channel inhibitor rescues the ligand-activated signal. This work identifies hyperactivated calcium signaling as the primary biological abnormality in GNAQ/11 mosaicism and paves the way for clinical trials with genetic or small molecule therapies.

GNAQ/GNA11 Mosaicism Is Associated with Abnormal Serum Calcium Indices and Microvascular Neurocalcification

Mosaic mutations in genes GNAQ or GNA11 lead to a spectrum of diseases including Sturge-Weber syndrome and phakomatosis pigmentovascularis with dermal melanocytosis. The pathognomonic finding of localized "tramlining" on plain skull radiography, representing medium-sized neurovascular calcification and associated with postnatal neurological deterioration, led us to study calcium metabolism in a cohort of 42 children. In this study, we find that 74% of patients had at least one abnormal measurement of calcium metabolism, the commonest being moderately low serum ionized calcium (41%) or high parathyroid hormone (17%). Lower levels of ionized calcium even within the normal range were significantly associated with seizures, and with specific antiepileptics despite normal vitamin D levels. Successive measurements documented substantial intrapersonal fluctuation in indices over time, and DEXA scans were normal in patients with hypocalcemia. Neurohistology from epilepsy surgery in five patients revealed not only intravascular, but perivascular and intraparenchymal mineral deposition and intraparenchymal microvascular disease in addition to previously reported findings. Neuroradiology review clearly demonstrated progressive calcium deposition in individuals over time. These findings and those of the adjoining paper suggest that calcium deposition in the brain of patients with GNAQ/GNA11 mosaicism may not be a nonspecific sign of damage as was previously thought, but may instead reflect the central postnatal pathological process in this disease spectrum.

Uveal melanoma modeling in mice and zebrafish

Despite extensive research and refined therapeutic options, the survival for metastasized uveal melanoma (UM) patients has not improved significantly. UM, a malignant tumor originating from melanocytes in the uveal tract, can be asymptomatic and small tumors may be detected only during routine ophthalmic exams; making early detection and treatment difficult. UM is the result of a number of characteristic somatic alterations which are associated with prognosis. Although UM morphology and biology have been extensively studied, there are significant gaps in our understanding of the early stages of UM tumor evolution and effective treatment to prevent metastatic disease remain elusive. A better understanding of the mechanisms that enable UM cells to thrive and successfully metastasize is crucial to improve treatment efficacy and survival rates. For more than forty years, animal models have been used to investigate the biology of UM. This has led to a number of essential mechanisms and pathways involved in UM aetiology. These models have also been used to evaluate the effectiveness of various drugs and treatment protocols. Here, we provide an overview of the molecular mechanisms and pharmacological studies using mouse and zebrafish UM models. Finally, we highlight promising therapeutics and discuss future considerations using UM models such as optimal inoculation sites, use of BAP1mut-cell lines and the rise of zebrafish models.

Serous Retinal Detachment in a Patient With a Port-Wine Birthmark Associated With Prostaglandin Analog Therapy

An 11-year-old girl with a port-wine birthmark (PWB), diffuse choroid hemangioma (DCH), and glaucoma experienced decreased vision upon starting treatment with bimatoprost. The patient was switched to latanoprostene bunod. Her vision remained reduced. Shortly after, she was diagnosed with serous retinal detachment (SRD). Both SRD and vision improved following prostaglandin analog (PGA) cessation. Patients with PWB are likely to have DCH and glaucoma. DCH itself poses a risk factor for SRD. Certain glaucoma management modalities may further increase this risk. This report highlights the importance of regular surveillance for SRD in patients with DCH who are receiving PGA. [Ophthalmic Surg Lasers Imaging Retina 2023;54:723-729.].

Next-Generation sequencing transforming clinical practice and precision medicine

Next-generation sequencing (NGS) has revolutionized the field of genomics and is rapidly transforming clinical diagnosis and precision medicine. This advanced sequencing technology enables the rapid and cost-effective analysis of large-scale genomic data, allowing comprehensive exploration of the genetic landscape of diseases. In clinical diagnosis, NGS has proven to be a powerful tool for identifying disease-causing variants, enabling accurate and early detection of genetic disorders. Additionally, NGS facilitates the identification of novel disease-associated genes and variants, aiding in the development of targeted therapies and personalized treatment strategies. NGS greatly benefits precision medicine by enhancing our understanding of disease mechanisms and enabling the identification of specific molecular markers for disease subtypes, thus enabling tailored medical interventions based on individual characteristics. Furthermore, NGS contributes to the development of non-invasive diagnostic approaches, such as liquid biopsies, which can monitor disease progression and treatment response. The potential of NGS in clinical diagnosis and precision medicine is vast, yet challenges persist in data analysis, interpretation, and protocol standardization. This review highlights NGS applications in disease diagnosis, prognosis, and personalized treatment strategies, while also addressing challenges and future prospects in fully harnessing genomic potential within clinical practice.

Secondary developmental glaucoma

The basic pathophysiology of all childhood glaucoma results from impaired outflow through the trabecular meshwork. Anterior Segment Dysgeneses (ASD) are a group of nonacquired anomalies associated with secondary developmental glaucoma, characterized by impaired development of the structures of the anterior segment. Many genes impact the development of the anterior segment. The cause of the development of the abnormalities is thought to be multifactorial. Molecular research has helped our understanding of the molecular basis of ASD and the developmental mechanisms underlying these conditions. Identifying the genetic changes underlying ASD has gradually led to the recognition that some of these conditions may be parts of a disease spectrum rather than isolated anomalies. The characterization of the underlying genetic abnormalities responsible for glaucoma is the first step toward developing diagnostic and screening tests, which could identify individuals at risk for disease before irreversible optic nerve damage occurs. It is also crucial for genetic counseling and risk stratification of later pregnancies. It also aids prenatal testing by various methods allowing for effective genetic counseling. This review summarizes various ocular and systemic conditions that result in secondary developmental glaucoma and provide an overview of the phenotypes, the diagnosis and principles of management of the various disorders.

Cutis marmorata telangiectatica congenita: Incidence of extracutaneous manifestations and a proposed clinical definition

BACKGROUND/OBJECTIVES

Cutis marmorata telangiectatica congenita (CMTC) is a capillary malformation characterized by congenital, reticulated, well-demarcated dark blue, red-purple, or violaceous macules or plaques, with a coarse fixed livedo pattern. Nearly always, contiguous areas of skin atrophy and/or ulceration are present. CMTC is usually localized but may rarely be generalized. Such generalized cases may be a feature of Adams-Oliver syndrome (AOS). The nosologic confusion surrounding the term CMTC and uncertainty about the risk of associated abnormalities hinders the appropriate workup of patients and prognostic counseling for families. We hypothesized that the risk of associated anomalies in children with localized CMTC is very low.

METHODS

We performed a literature review and retrospective review of patients with CMTC to propose a more precise clinical definition and ascertain the risk of associated anomalies.

RESULTS

We included 78 patients determined to have a diagnosis of CMTC based on consensus. The majority of patients had localized CMTC. Most patients with generalized CMTC met the criteria for the diagnosis of AOS. The associations found in patients with localized CMTC were mostly dermatological, with atrophy, ulcerations, or erosions present in 71%. Extracutaneous findings were present in 34.4% of patients and consisted mainly of extremity asymmetry (24.5%) that improved over time.

CONCLUSION

Our study showed a very low frequency of extracutaneous anomalies among patients with localized CTMC, ipsilateral limb discrepancy being the most common. We did not find a strong association with any other visceral anomalies that would justify routine evaluation in patients with localized CMTC.

PTPN11 Mosaicism Causes a Spectrum of Pigmentary and Vascular Neurocutaneous Disorders and Predisposes to Melanoma

Phakomatosis pigmentovascularis is a diagnosis that denotes the coexistence of pigmentary and vascular birthmarks of specific types, accompanied by variable multisystem involvement, including CNS disease, asymmetrical growth, and a predisposition to malignancy. Using a tight phenotypic group and high-depth next-generation sequencing of affected tissues, we discover here clonal mosaic variants in gene PTPN11 encoding SHP2 phosphatase as a cause of phakomatosis pigmentovascularis type III or spilorosea. Within an individual, the same variant is found in distinct pigmentary and vascular birthmarks and is undetectable in blood. We go on to show that the same variants can cause either the pigmentary or vascular phenotypes alone, and drive melanoma development within pigmentary lesions. Protein structure modeling highlights that although variants lead to loss of function at the level of the phosphatase domain, resultant conformational changes promote longer ligand binding. In vitro modeling of the missense variants confirms downstream MAPK pathway overactivation and widespread disruption of human endothelial cell angiogenesis. Importantly, patients with PTPN11 mosaicism theoretically risk passing on the variant to their children as the germline RASopathy Noonan syndrome with lentigines. These findings improve our understanding of the pathogenesis and biology of nevus spilus and capillary malformation syndromes, paving the way for better clinical management.

Outcomes of Microcatheter-Assisted Trabeculotomy for Glaucoma Associated With Sturge-Weber Syndrome and Phakomatosis Pigmentovascularis

PURPOSE

To evaluate mid-term efficacy and safety of ab externo Microcatheter-assisted trabeculotomy (MAT) for early-onset glaucoma associated with Sturge-Weber syndrome (SWS) and phakomatosis pigmentovascularis (PPV).

DESIGN

Retrospective, non-comparative, interventional case series.

METHODS

Medical records of consecutive SWS- or PPV-associated glaucoma patients who had undergone ab externo MAT between August 2017 and April 2020 at Beijing Children's Hospital were reviewed. Success was defined as an intraocular pressure (IOP) of <21 mmHg with (qualified success) or without (complete success) the use of antiglaucoma medication.

RESULTS

Overall, 13 eyes (12 patients) with SWS and 9 eyes (8 patients) with PPV were included, with a mean age of 12.8 ± 15.8 months at the time of surgery and a mean follow-up time of 39.5 ±10.4 months. Both the SWS (26.5 ± 5.3 mmHg at baseline vs 16.5 ± 5.0 mmHg at the last visit; P < .001) and PPV (29.2 ± 7.5 mmHg vs 23.4 ± 4.7 mmHg; P = .014) subsets achieved a statistically significant fall in IOP following surgery. The Kaplan-Meier survival rate of complete (qualified) success after 42 months was 76.2% (87.5%) and 22.2% (40.0%) for eyes with SWS and PPV, respectively. Complications were minimal. Phakomatosis pigmentovascularis was associated with worse surgical outcomes.

CONCLUSIONS

Ab externo MAT is an effective and safe treatment for early-onset glaucoma associated with SWS, but a gradual increase in IOP over time was noted in some patients. Ab externo MAT has limited efficacy for early-onset glaucoma associated with PPV in the mid-term.

Genetic testing in the evaluation of individuals with clinical diagnosis of atypical Sturge-Weber syndrome

Sturge-Weber Syndrome (SWS) is a rare vascular malformation disorder characterized by abnormal blood vessels in the brain, skin, and eye. SWS is most commonly caused by a somatic mosaic GNAQ-p.Arg183Gln variant. In this series, 12 patients presented for clinical evaluation of SWS but were noted to have atypical features, and therefore germline and/or somatic genetic testing was performed. Atypical features included extensive capillary malformation on the body as well as the face, frontal bossing, macrocephaly, telangiectasia, overgrowth of extremities, absence of neurologic signs and symptoms, and family history of vascular malformations. Five patients had a somatic GNAQ or GNA11 pathogenic variant, one patient had a somatic mosaic likely-pathogenic variant in PIK3CA, and another one had a somatic mosaic deletion that disrupted PTPRD. The other five patients had germline variants in RASA1, EPHB4, or KIT. Our findings suggest that patients presenting for SWS evaluation who have atypical clinical characteristics may have pathogenic germline or somatic variants in genes other than GNAQ or GNA11. Broad germline and somatic genetic testing in these patients with atypical findings may have implications for medical care, prognosis, and trial eligibility.

CHOROIDAL MELANOMA IN PHAKOMATOSIS PIGMENTOVASCULARIS WITH OVERLAPPING STURGE-WEBER SYNDROME AND KLIPPEL-TRENAUNAY SYNDROME

PURPOSE

To present the rare occurrence of choroidal melanoma in an adult patient with phakomatosis pigmentovascularis and an overlap of Sturge-Weber syndrome and Klippel-Trenaunay syndrome.

METHODS

Observational case report.

RESULTS

A 75-year-old White woman with nevus flammeus involving the left forehead, periorbital area, cheek, chin, upper limb, and trunk, along with hemihypertrophy of the left side of the face and left upper limb, presented for evaluation of an intraocular mass in the left eye. Anterior examination of the left eye showed diffuse episcleral and iris melanocytosis. Fundus examination of the left eye showed diffuse choroidal melanocytosis and an elevated choroidal lesion. B-scan ultrasonography demonstrated a hollow lesion, and the patient was diagnosed with choroidal melanoma in the left eye in the setting of phakomatosis pigmentovascularis with overlap of Sturge-Weber syndrome and Klippel-Trenaunay syndrome. Fine-needle aspiration biopsy confirmed the diagnosis, and Iodine 125 plaque radiotherapy was performed.

CONCLUSION

Individuals with clinical features suggestive of phakomatosis pigmentovascularis, Sturge-Weber syndrome, or Klippel-Trenaunay syndrome should undergo a complete ophthalmological evaluation for the presence of ocular melanocytosis and uveal melanoma.

Melanocytic naevi, melanocytomas and emerging concepts

With the elucidation of the genetics of melanocytic tumours, new concepts have emerged. An important one is the identification of 'intermediate' melanocytic tumours, those with genetic progression events beyond those of melanocytic naevi but that are not fully malignant. Thus, melanocytic tumours exist on a genetic spectrum that likely corresponds to biological behaviour. There are multiple pathways to melanoma development with different initiating events and characteristic benign melanocytic neoplasms and the precise placement of tumours on these pathways remains to be established and the corresponding risks of progression quantified. In this review, I discuss the classification of melanocytic naevi based on clinical, histopathological and genetic features, as well as the concept of melanocytomas with discussion of specific recognisable subtypes.

Sturge-Weber Syndrome: A Review of Pathophysiology, Genetics, Clinical Features, and Current Management Approache

Sturge-Weber syndrome (SWS) is a congenital, sporadic, and rare neurocutaneous disorder, characterized by the presence of a facial port-wine birthmark (PWB), glaucoma, and neurological manifestations including leptomeningeal angiomatosis and seizures. It is caused by a postzygotic, somatic, gain-of-function variant of the GNAQ gene, and more recently, the GNA11 gene in association with distinctive clinical features. Neuroimaging can help identify and stratify patients at risk for significant complications allowing closer follow-up; although no presymptomatic treatment has been demonstrated to be effective to date, these patients could benefit from early treatment and/or supportive interventions. Choroid plexus (CP) thickness measurements in brain magnetic resonance imaging (MRI) have a high sensitivity and specificity for early and incipient changes in SWS. In contrast, the absence of pathologic findings makes it possible to rule out associated neurological involvement and leads to periodical observation, with new imaging studies only in cases of new clinical signs/symptoms. Periodic ophthalmological examination is also recommended every 3 months during the first year and yearly afterwards to monitor for glaucoma and choroidal hemangiomas. Treatment for SWS depends on the extent and areas that are affected. These include laser surgery for PWB, anticonvulsants in the case of brain involvement, with either seizures or abnormal EEG, and medical treatment or surgery for glaucoma. Sirolimus has been used in a limited number of patients and appears to be a safe and potentially effective treatment for cutaneous and extra-cutaneous features, however controlled clinical studies have not been carried out. Better knowledge of GNAQ/GNA11 molecular pathways will help to develop future targeted treatments.

Case Report: 2-Year-old With Wilms Tumors, Familial Heterozygous DIS3L2 Mutation, and Cutis Marmorata Telangiectatica Congenita

Biallelic variants in DI3SL2 cause Perlman Syndrome, associated increased risk for Wilms tumor. Cutis Marmorata Telangiectatica Congenita (CMTC) is a rare congenital disorder characterized by cutaneous vascular anomalies. We report a 2-year-old boy with both Wilms tumor and CMTC. Genetic testing, prompted by his complex presentation, revealed 1 somatic mutation and 1 familial germline mutation in the DIS3L2 gene, suggesting a 2-hit causation of Wilms tumor. Separately, a single GNA11 somatic mutation was identified to explain the CMTC. We suggest that genetic testing for germline mutations associated with Wilms tumor susceptibility be considered even in cases without known family history.

Early-onset hypertension associated with extensive cutaneous capillary malformations harboring postzygotic variants in GNAQ and GNA11

BACKGROUND AND OBJECTIVES

Cutaneous capillary malformations (CMs) describe a group of vascular birthmarks with heterogeneous presentations. CMs may present as an isolated finding or with other associations, including glaucoma and leptomeningeal angiomatosis (i.e., Sturge-Weber syndrome) or pigmentary birthmarks (i.e., phakomatosis pigmentovascularis). The use of targeted genetic sequencing has revealed that postzygotic somatic variations in GNAQ and GNA11 at codon 183 are associated with CMs. We report five patients with early-onset hypertension and discuss possible pathogenesis of hypertension.

METHODS

Twenty-nine patients with CMs, confirmed GNAQ/11 postzygotic variants, and documented past medical history were identified from a multi-institutional vascular anomalies study. Early-onset hypertension was defined as hypertension before the age of 55 years. Clinical data were reviewed for evidence of hypertension, such as documentation of diagnosis or elevated blood pressure measurements.

RESULTS

Five of the 29 patients identified as having GNAQ/11 postzygotic variants had documented early-onset hypertension. Three individuals harbored a GNAQ p.R183Q variant, and two individuals harbored a GNA11 p.R183C variant. All individuals had extensive cutaneous CMs involving the trunk and covering 9%-56% of their body surface area. The median age of hypertension diagnosis was 15 years (range 11-24 years), with three individuals having renal abnormalities on imaging.

CONCLUSIONS

Early-onset hypertension is associated with extensive CMs harboring somatic variations in GNAQ/11. Here, we expand on the GNAQ/11 phenotype and hypothesize potential mechanisms driving hypertension. We recommend serial blood pressure measurements in patients with extensive CMs on the trunk and extremities to screen for early-onset hypertension.

Postzygotic mutations and where to find them - Recent advances and future implications in the field of non-neoplastic somatic mosaicism

The technological progress of massively parallel sequencing (MPS) has triggered a remarkable development in the research on postzygotic mutations. Although the overwhelming majority of studies in the field focus on oncogenesis, non-neoplastic diseases are attracting more and more attention. The aim of this review was to summarize some of the most recent findings in the field of somatic mosaicism in diseases other than neoplastic events. We discuss the abundance and role of postzygotic mutations, with a special emphasis on disorders which occur only in a mosaic form (obligatory mosaic diseases; OMDs). Based on the list of OMDs compiled from the published literature and three databases (OMIM, Orphanet and MosaicBase), we demonstrate the prevalence of cancer-related genes across OMDs and suggest other sources to further explore OMDs and OMD-related genes. Additionally, we comment on some practical aspects related to mosaic diseases, such as approaches to tissue sampling, the MPS coverage required to detect variants at a very low frequency, as well as on bioinformatic and molecular tools dedicated to detect somatic mutations in MPS data.

Anterior segment dysgenesis: Insights into the genetics and pathogenesis

Childhood glaucoma is a treatable cause of blindness, provided it is recognized, diagnosed, and treated in time. WHO has estimated that it is responsible for Blind Years second only to cataracts. The fundamental pathophysiology of all childhood glaucoma is impaired outflow through the trabecular meshwork. Anterior segment Dysgeneses (ASD) are a group of non-acquired ocular anomalies associated with glaucoma, characterized by developmental abnormalities of the tissues of the anterior segment. The cause is multifactorial, and many genes are involved in the development of the anterior segment. Over the last decade, molecular and developmental genetic research has transformed our understanding of the molecular basis of ASD and the developmental mechanisms underlying these conditions. Identifying the genetic changes underlying ASD has gradually led to the recognition that some of these conditions may be parts of a disease spectrum. The characterization of genes responsible for glaucoma is the critical first step toward developing diagnostic and screening tests, which could identify individuals at risk for disease before irreversible optic nerve damage occurs. It is also crucial for genetic counseling and risk stratification of later pregnancies. It also aids pre-natal testing by various methods allowing for effective genetic counseling. This review will summarize the known genetic variants associated with phenotypes of ASD and the possible significance and utility of genetic testing in the clinic.

GNA11-mutated Sturge-Weber Syndrome has distinct neurologic and dermatologic features

BACKGROUND

Sturge-Weber syndrome (SWS) is a neurocutaneous disorder characterized by clinical manifestations involving the brain, eye and skin. SWS is commonly caused by somatic mutations in G protein subunit Alpha Q (GNAQ). Subunit Alpha 11 (GNA11) mutations have been reported in 5 cases. It is not clear if their phenotypic features differ.

METHODS

Within two European multidisciplinary centers we looked for patients with clinical characteristics of SWS and a GNA11 mutation. Clinical and radiological data was collected retrospectively and prospectively.

RESULTS

We identified three patients with SWS associated with a somatic GNA11 mutation. They had disseminated capillary malformation (CM) and hyper- or hypotrophy of an extremity. At birth, the CMs of the face, trunk and limbs were pink and patchy, and slowly darkened with age evolving to purple color. Two of the patients had glaucoma. All had neurological symptoms and moderate brain atrophy at a lower degree of severity than classically associated with SWS. Susceptibility-Weighted Images (SWI) and contrast-enhanced (CE) Fluid Attenuated Inversion Recovery (FLAIR) MR views demonstrated best sensitivity to reveal the pial angiomas.

CONCLUSIONS

We differentiate two distinct clinical/radiological phenotypes of SWS; GNAQ- and GNA11-SWS. The classical GNAQ-SWS is characterized by a homogeneous dark-red CM commonly associated with underlying soft tissue hypertrophy. The CM in GNA11-SWS is more reticulate and darkens with time; neurological picture is milder. SWI and post contrast FLAIR sequences appear to be necessary to demonstrate the leptomeningeal angiomatosis. Yet, anti-epileptic medication or future targeted therapies may be useful, like in classic SWS.

The Zebrafish model in dermatology: an update for clinicians

Recently, the zebrafish has been established as one of the most important model organisms for medical research. Several studies have proved that there is a high level of similarity between human and zebrafish genomes, which encourages the use of zebrafish as a model for understanding human genetic disorders, including cancer. Interestingly, zebrafish skin shows several similarities to human skin, suggesting that this model organism is particularly suitable for the study of neoplastic and inflammatory skin disorders. This paper appraises the specific characteristics of zebrafish skin and describes the major applications of the zebrafish model in dermatological research.

A novel somatic mutation in GNAQ in a capillary malformation provides insight into molecular pathogenesis

Sturge-Weber syndrome (SWS) is a sporadic, congenital, neuro-cutaneous disorder characterized by a mosaic, capillary malformation. SWS and non-syndromic capillary malformations are both caused by a somatic activating mutation in GNAQ encoding the G protein subunit alpha-q protein. The missense mutation R183Q is the sole GNAQ mutation identified thus far in 90% of SWS-associated or isolated capillary malformations. In this study, we sequenced skin biopsies of capillary malformations from 9 patients. We identified the R183Q mutation in nearly all samples, but one sample exhibited a Q209R mutation. This new mutation occurs at the same residue as the constitutively-activating Q209L mutation, commonly seen in tumors. However, Q209R is a rare variant in this gene. To compare the effect of the Q209R mutation on downstream signaling, we performed reporter assays with a GNAQ-responsive reporter co-transfected with either GNAQ WT, R183Q, Q209L, Q209R, or C9X (representing a null allele). Q209L showed the highest reporter activation, with R183Q and Q209R showing significantly lower activation. To determine whether these mutations had similar or different downstream consequences we performed RNA-seq analysis in microvascular endothelial cells (HMEC-1) electroporated with the same GNAQ variants. The R183 and Q209 missense variants caused extensive dysregulation of a broad range of transcripts compared to the WT or null allele, confirming that these are all activating mutations. However, the missense variants exhibited very few differentially expressed genes (DEGs) when compared to each other. These data suggest that these activating GNAQ mutations differ in magnitude of activation but have similar downstream effects.

Phakomatosis pigmentovascularis type Ⅲa mainly manifested by zosteriform nevus spilus: a case report with dermoscopic features

A case of phakomatosis pigmentovascularis (PPV) type III a with a zosteriform distribution of nevus spilus as the main manifestation was reported. A 41-year-old man was born with a zosteriform distribution of pigmented rash on the left half-body, namely upper limb, shoulder and back. Physical examination revealed light brown pigments in a giant zosteriform distribution on the extensor side of the left upper limb and the left shoulder and back, with scattered brown spots and patches of variant sizes on the surface, which are consistent with the appearance of nevus spilus (NS). A relatively small area of dark red patch occurred on the left anterior shoulder, which showed telangiectasia and fading after pressing. It was consistent with the performance of a port-wine stain (PWS). Dermoscopy showed a clearer appearance and localized fusion of blood vessels and pigmented patch. He has no systemic involvement. The patient was diagnosed with phakomatosis pigmentovascularis type Ⅲa. NS and PWS can be treated with lasers if required.

Bilateral Phakomatosis Cesiomarmorata With Ocular Melanocytosis and Secondary Glaucoma

Phakomatosis pigmentovascularis (PPV) is a family of rare congenital diseases where vascular malformation coexists with melanocytic, dermal, or ocular lesions. The cesiomarmorata type is even rarer, and most such cases are reported with unilateral occurrence. We present an atypical case of a patient with bilateral phakomatosis cesiomarmorata, bilateral ocular melanocytosis, and bilateral glaucoma. No malformation to resist aqueous drainage was identified. Long-term management of intraocular pressure (IOP) using topical antiglaucoma medication was successful. This case report refines the clinical presentation of phakomatosis cesiomarmorata and may help diagnose and treat future cases.

Genodermatoses associated with melanocytic nevi

Though melanocytic nevi are ubiquitous in the general population, they can also be key cutaneous manifestations of genetic syndromes. We describe genodermatoses associated with melanocytic nevi and discuss their clinical characteristics, cutaneous manifestations, underlying genetics, and, if applicable, guidelines for when genetic testing should be performed. We categorized these genodermatoses based on their association with congenital nevi, acquired nevi, or nevi whose first appearance is unknown. In many cases, the distinctive morphology or distribution of melanocytic nevi can be an important clue that an underlying genetic syndrome is present, allowing both the patient as well as family members to be screened for the more serious complications of their genetic disorder and receive education on potential preventative measures. As we continue to advance our understanding of how various genotypes give rise to the wide spectrum of phenotypes observed in these genodermatoses, we shall be able to better stratify risk and tailor our screening methods to clinically manage the heterogeneous manifestations of genodermatoses among these patients.

Phacomatosis pigmentovascularis with sturge-weber syndrome and congenital glaucoma: A rare case report

Phacomatosis pigmentovascularis (PPV) is a rare congenital disease characterized by the co-existence of cutaneous vascular malformation and pigmentary nevi with or without extracutaneous systemic involvement. Here, we present a 2-month old child diagnosed with phacomatosis cesioflammea type of PPV with Sturge-Weber syndrome and secondary congenital glaucoma of the left eye. She underwent combined trabeculotomy and trabeculectomy in the left eye for glaucoma and was started on anti-epileptics for seizure control following pediatric evaluation. Early screening and treatment initiation can prevent blindness and other systemic complications associated with PPV.

Concomitant variants in NF1, LZTR1 and GNAZ genes probably contribute to the aggressiveness of plexiform neurofibroma and warrant treatment with MEK inhibitor

Neurofibromatosis 1 (NF1) is caused by germline mutations in the NF1 gene and manifests as proliferation of various tissues, including plexiform neurofibromas. The plexiform neurofibroma phenotype varies from indolent to locally aggressive, suggesting contributions of other modifiers in addition to somatic loss of NF1. In this study, we investigated a life-threatening plexiform neurofibroma in a 9-month-old female infant with NF1. Germline mutations in two RASopathy-associated genes were identified using whole-exome sequencing-a de novo pathogenic variant in the NF1 gene, and a known pathogenic variant in the LZTR1 gene. Somatic analysis of the plexiform neurofibroma revealed NF1 loss of heterozygosity and a variant in GNAZ, a gene encoding a G protein-coupled receptor. Cells expressing mutant GNAZ exhibited increased ERK 1/2 activation compared to those expressing wild-type GNAZ. Taken together, we suggest the variants in NF1, LZRT1 and GNAZ act synergistically in our patient, leading to MAPK pathway activation and contributing to the severity of the patient's plexiform neurofibromatosis. After treatment with the MEK inhibitor, trametinib, a prominent clinical improvement was observed in this patient. This case study contributes to the knowledge of germline and somatic non-NF1 variants affecting the NF1 clinical phenotype and supports use of personalized, targeted therapy.

Large Plaque-type Blue Nevus with GNAQ Q209P Mutation, Involving Mammary Gland Tissue: Under-Recognized Mammary Condition as an Origin of Primary Mammary Melanocytic Tumors

ABSTRACT

Plaque-type blue nevus is a rare variant of blue nevi that was first described in 1954. This article presents clinical, macroscopic, histopathological, and genetic findings for a case of large plaque-type blue nevus expanding into the mammary gland tissue as well as the skin of the right breast. A 63-year-old woman presented with a congenital, large, blue-colored macule limited to the hypochondriac area of the right breast. A nodule 8 mm in diameter was also present in the mammary gland tissue. Magnetic resonance imaging was unable to detect diffuse melanin deposition in the mammary gland tissue, but pigmentation in the whole mammary parenchyma was observed in the cut surfaces of the mastectomy specimen. Histopathology revealed a sparse distribution of dendritic melanocytes in whole sections of the mammary fibrous tissue and partial sections of the dermis. The histopathological criteria for atypical cellular blue nevus were fulfilled for the mammary tumor. Nodal blue nevus was diagnosed in the sentinel lymph node. Sanger sequencing confirmed the GNAQ Q209P mutation, which was also identified in all 4 literature cases of plaque-type blue nevus, but rarely in conventional blue nevi and uveal melanoma. It should be noted that plaque-type blue nevus can expand into the mammary gland tissue, even if the pigmented lesion does not exist on the overlying breast skin. The mammary condition can be the origin of primary mammary melanocytic tumors. Mosaicism of the GNAQ Q209P mutation can be a characteristic genetic alteration to extensive blue nevi, including plaque-type blue nevus.

Acne Syndromes and Mosaicism

Abnormal mosaicism is the coexistence of cells with at least two genotypes, by the time of birth, in an individual derived from a single zygote, which leads to a disease phenotype. Somatic mosaicism can be further categorized into segmental mosaicism and nonsegmental somatic mosaicism. Acne is a chronic illness characterized by inflammatory changes around and in the pilosebaceous units, commonly due to hormone- and inflammatory signaling-mediated factors. Several systemic disorders, such as congenital adrenal hyperplasia, polycystic ovarian syndrome, and seborrhoea-acne-hirsutism-androgenetic alopecia syndrome have classically been associated with acne. Autoinflammatory syndromes, including PAPA, PASH, PAPASH, PsAPASH, PsaPSASH, PASS, and SAPHO syndromes include acneiform lesions as a key manifestation. Mosaic germline mutations in the FGFR2 gene have been associated with Apert syndrome and nevus comedonicus, two illnesses that are accompanied by acneiform lesions. In this review, we summarize the concept of cutaneous mosaicism and elaborate on acne syndromes, as well as acneiform mosaicism.

Somatic mutations of GNA11 and GNAQ in CTNNB1-mutant aldosterone-producing adenomas presenting in puberty, pregnancy or menopause

Most aldosterone-producing adenomas (APAs) have gain-of-function somatic mutations of ion channels or transporters. However, their frequency in aldosterone-producing cell clusters of normal adrenal gland suggests a requirement for codriver mutations in APAs. Here we identified gain-of-function mutations in both CTNNB1 and GNA11 by whole-exome sequencing of 3/41 APAs. Further sequencing of known CTNNB1-mutant APAs led to a total of 16 of 27 (59%) with a somatic p.Gln209His, p.Gln209Pro or p.Gln209Leu mutation of GNA11 or GNAQ. Solitary GNA11 mutations were found in hyperplastic zona glomerulosa adjacent to double-mutant APAs. Nine of ten patients in our UK/Irish cohort presented in puberty, pregnancy or menopause. Among multiple transcripts upregulated more than tenfold in double-mutant APAs was LHCGR, the receptor for luteinizing or pregnancy hormone (human chorionic gonadotropin). Transfections of adrenocortical cells demonstrated additive effects of GNA11 and CTNNB1 mutations on aldosterone secretion and expression of genes upregulated in double-mutant APAs. In adrenal cortex, GNA11/Q mutations appear clinically silent without a codriver mutation of CTNNB1.

Outcomes of Management of Glaucoma in Phacomatosis Pigmentovascularis Over the Last Three Decades: A Single-Center Experience

PURPOSE

To report the clinical outcomes of glaucoma management in patients with phacomatosis pigmentovascularis (PPV) treated over a period of 3 decades.

DESIGN

Retrospective cohort study.

PARTICIPANTS

Fifty-five eyes of 38 patients (21 unilateral and 17 bilateral) with glaucoma in PPV managed at one institution between January 1990 and December 2019 with a minimum follow-up of 1 year.

METHODS

Medical records of children with glaucoma in PPV were reviewed, and demographic and clinical data were collected. Surgical interventions included primary combined trabeculotomy-trabeculectomy (CTT), trabeculectomy with mitomycin C (MMC), and transscleral cyclophotocoagulation (TSCPC). Complete success was defined as intraocular pressure (IOP) ≥ 6 and ≤ 16 mmHg without medications and qualified success as IOP ≤ 16 mmHg with the use of up to 2 medications.

MAIN OUTCOME MEASURES

Intraocular pressure, best-corrected visual acuity (BCVA), corneal clarity, antiglaucoma medications at preoperative and postoperative visits (last visit), and complications.

RESULTS

Median age was 4 months (range, 0.2-252 months) at the time of glaucoma surgery. Thirty-nine eyes (74%) had primary CTT, 10 eyes (19%) had trabeculectomy with MMC, and 4 eyes (7%) with advanced glaucoma had TSCPC. Two eyes (3.6%) received medical treatment. Preoperative IOP reduced from a mean of 25.7 ± 8.4 mmHg on 0.8 ± 0.6 medications to 14.6 ± 5.2 mmHg on 0.4 ± 0.5 medications (P < 0.0001) at last follow-up after surgery (77.7 ± 56.5 months). Thirty-seven eyes (67.3%) required medications preoperatively, and 22 eyes (40%) required medications at the last follow-up. Of 25 patients with available BCVA at last follow-up, 9 (36%) had ≥ 20/60; of these, 6 had > 20/40. Four of 10 eyes that underwent trabeculectomy with MMC developed retinal detachment and were managed surgically; however, all of these eyes had poor visual outcomes. There was no incidence of bleb leakage, bleb-related infection, or endophthalmitis.

CONCLUSIONS

Combined trabeculotomy-trabeculectomy is safe and effective as a primary procedure for management of glaucoma in PPV. Trabeculectomy augmented with MMC as a second procedure was associated with a higher rate of complications.

Pathogenic postzygotic mosaicism in the tyrosine receptor kinase pathway: potential unidentified human disease hidden away in a few cells

Mutations occurring during embryonic development affect only a subset of cells resulting in two or more distinct cell populations that are present at different levels, also known as postzygotic mosaicism (PZM). Although PZM is a common biological phenomenon, it is often overlooked as a source of disease due to the challenges associated with its detection and characterization, especially for very low-frequency variants. Moreover, PZM can cause a different phenotype compared to constitutional mutations. Especially, lethal mutations in receptor tyrosine kinase (RTK) pathway genes, which exist only in a mosaic state, can have completely new clinical manifestations and can look very different from the associated monogenic disorder. However, some key questions are still not addressed, such as the level of mosaicism resulting in a pathogenic phenotype and how the clinical outcome changes with the development and age. Addressing these questions is not trivial as we require methods with the sensitivity to capture some of these variants hidden away in very few cells. Recent ultra-accurate deep-sequencing approaches can now identify these low-level mosaics and will be central to understand systemic and local effects of mosaicism in the RTK pathway. The main focus of this review is to highlight the importance of low-level mosaics and the need to include their detection in studies of genomic variation associated with disease.

Cutaneous manifestations in Moyamoya angiopathy: A review

BACKGROUND AND PURPOSE

Moyamoya angiopathy (MA) is a progressive cerebrovascular disease with a poorly understood pathophysiology. It is mainly characterized by progressive bilateral stenosis of the terminal intracranial part of the supraclinoid internal carotid arteries and the proximal parts of the middle and anterior cerebral arteries. This results in early-onset ischemic or hemorrhagic strokes. The disease may be idiopathic (known as Moyamoya disease) or associated with other heritable or acquired conditions, including type 1 neurofibromatosis or other RASopathies, sickle cell disease, Down syndrome, or autoimmune disorders (known as Moyamoya syndrome). Apart from the brain, other organ manifestations including cutaneous ones have also been described in MA patients.

MATERIALS AND METHODS

A literature research on PubMed was performed for articles mentioning the cutaneous association in MA and published between 1994 and October 2020.

CONCLUSION

The present review summarizes the cutaneous associations as well as the coincidental dermatological findings seen in MA patients. Those include changes in the epidermis, dermis, or skin appendages for example café-au-lait spots, hypomelanosis of Ito, livedo racemosa, hemangiomas, premature graying of hair, chilblains etc.

Functional characterization of uveal melanoma oncogenes

Uveal melanoma (UM) is a currently untreatable form of melanoma with a 50% mortality rate. Characterization of the essential signaling pathways driving this cancer is critical to develop target therapies. Activating mutations in the Gαq signaling pathway at the level of GNAQ, GNA11, or rarely CYSLTR2 or PLCβ4 are considered alterations driving proliferation in UM and several other neoplastic disorders. Here, we systematically examined the oncogenic signaling output of various mutations recurrently identified in human tumors. We demonstrate that CYSLTR2 → GNAQ/11 → PLCβ act in a linear signaling cascade that, via protein kinase C (PKC), activates in parallel the MAP-kinase and FAK/Yes-associated protein pathways. Using genetic ablation and pharmacological inhibition, we show that the PKC/RasGRP3/MAPK signaling branch is the essential component that drives the proliferation of UM. Only inhibition of the MAPK branch but not the FAK branch synergizes with inhibition of the proximal cascade, providing a blueprint for combination therapy. All oncogenic signaling could be extinguished by the novel GNAQ/11 inhibitor YM-254890, in all UM cells with driver mutation in the Gαq subunit or the upstream receptor. Our findings highlight the GNAQ/11 → PLCβ → PKC → MAPK pathway as the central signaling axis to be suppressed pharmacologically to treat for neoplastic disorders with Gαq pathway mutations.

Ocular manifestations in phakomatosis pigmentovascularis: Current concepts on pathogenesis, diagnosis, and management

Phakomatosis pigmentovascularis is a rare congenital multisystemic disease with variable manifestations where a vascular malformation of the skin is associated with a pigmentary nevus. Ocular involvement includes glaucoma, choroidal hemangioma, and pigmentary alterations that predispose to uveal melanoma. Diagnosis is made on clinical grounds, although recent advances in molecular genetics have better clarified the etiopathogenesis of the condition. The advent of improved imaging techniques such as enhanced depth imaging spectral domain optical coherence tomography has provided new insight into the ocular alterations, enabling better follow-up of patients. We review the ophthalmic manifestations of the disease with an update on etiopathogenesis and current management strategies.

Retinal manifestations of the neurocutaneous disorders

PURPOSE OF REVIEW

The neurocutaneous disorders are a genetically and phenotypically diverse group of congenital syndromes characterized by cutaneous, ocular, and central nervous system manifestations. This review provides an overview of the clinical features and retinal findings in selected neurocutaneous disorders.

RECENT FINDINGS

Advances in genetics and diagnostic retinal and neuroimaging allow for the recognition of retinal features of common neurocutaneous syndromes and for improved characterization of rarer entities based on previously underdiagnosed or unrecognized retinal findings.

SUMMARY

Better characterization of the neurocutaneous disorders allows for earlier recognition and the potential for expeditious vision-saving and life-saving treatment.