RAS proteins regulate cell division, differentiation, and apoptosis through multiple downstream effector pathways. Oncogenic RAS variants are the commonest drivers in cancers; however, they also drive many benign lesions predisposing to malignancy, such as melanocytic nevi, thyroid nodules, and colonic polyps. Reversal of these benign lesions could reduce cancer incidence; however, the effects of oncogenic RAS have been notoriously difficult to target with downstream pathway inhibitors.
View Article and Find Full Text PDFCongenital melanocytic nevi (CMN) are rare, pigmented birthmarks that can predispose patients to melanoma of the central nervous system and skin. Data from non-CMN melanoma cohorts suggest that vitamin D levels may be connected to outcome, prompting this study of 25-hydroxyvitamin D levels in plasma samples from 40 children with CMN. While 27% were insufficient and 13% deficient, this was representative of European populations, and UK supplementation guidelines are already in place.
View Article and Find Full Text PDFMosaic 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%).
View Article and Find Full Text PDFMosaic 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.
View Article and Find Full Text PDFAmong children with multiple congenital melanocytic nevi, 25% have no established genetic cause, of whom many develop a hyperproliferative and severely pruritic phenotype resistant to treatment. Gene fusions have been reported in individual cases of congenital melanocytic nevi. We studied 169 patients with congenital melanocytic nevi in this study, 38 of whom were double wild type for pathogenic NRAS/BRAF variants.
View Article and Find Full Text PDFBackground: The importance of photographs in social media, the steep rise in popularity of tattoos, and the prominence of individuals with visibly different skin in fashion are likely to be changing the landscape of self- and public perception of birthmarks. Study objectives were to assess the impact of a photoshoot and public exhibition on the self-perception of individuals with extensive birthmarks, and to explore the viewing public's reactions.
Methods: Thirty individuals with congenital melanocytic nevi (CMN) were recruited internationally.
Congenital melanocytic naevus (CMN) syndrome, previously termed neurocutaneous melanosis, is a rare disease caused by postzygotic mosaic mutations occurring during embryogenesis in precursors of melanocytes. The severity of neurological manifestations in CMN patients is related to central nervous system abnormalities found at magnetic resonance imaging. The association between CMN and Dandy-Walker malformation (DWM) has been described in the literature, but recent advances in imaging and genetics lead to diagnostic criteria revision.
View Article and Find Full Text PDFWe describe a mosaic PRKACA duplication in a young infant who presented with a Carney-like complex: bilateral non-pigmented micronodular adrenal hyperplasia, severe early-onset Cushing's syndrome, and distinct acral soft tissue overgrowth due to cutaneous mucinosis. This represents a novel manifestation of PRKACA disruption and broadens the extra-adrenal phenotype of PRKACA-associated Cushing's syndrome. Our data suggest that Cushing's syndrome phenotypes arising from somatic and germline PRKACA abnormalities can exist on a spectrum.
View Article and Find Full Text PDFPhakomatosis 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.
View Article and Find Full Text PDFDyskeratosis congenita (DC) is an inherited bone-marrow-failure disorder characterized by a triad of mucocutaneous features that include abnormal skin pigmentation, nail dystrophy, and oral leucoplakia. Despite the identification of several genetic variants that cause DC, a significant proportion of probands remain without a molecular diagnosis. In a cohort of eight independent DC-affected families, we have identified a remarkable series of heterozygous germline variants in the gene encoding thymidylate synthase (TYMS).
View Article and Find Full Text PDFMost 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.
View Article and Find Full Text PDFEpidermal choristoma is a rare, congenital lesion in which islands of ectopic skin are found within the oral cavity. They present as pigmented macules or papules on the tongue. Histologic appearances are characteristic and benign.
View Article and Find Full Text PDFPurpose: Much of the heredity of melanoma remains unexplained. We sought predisposing germline copy-number variants using a rare disease approach.
Methods: Whole-genome copy-number findings in patients with melanoma predisposition syndrome congenital melanocytic nevus were extrapolated to a sporadic melanoma cohort.
Purpose: Hypomelanosis of Ito (HI) is a skin marker of somatic mosaicism. Mosaic MTOR pathogenic variants have been reported in HI with brain overgrowth. We sought to delineate further the pigmentary skin phenotype and clinical spectrum of neurodevelopmental manifestations of MTOR-related HI.
View Article and Find Full Text PDFKeratinocytic epidermal nevi (KEN) are characterized clinically by permanent hyperkeratosis in the distribution of Blaschko's lines and histologically by hyperplasia of epidermal keratinocytes. KEN with underlying RAS mutations have been associated with hypophosphatemic rickets and dysplastic bone lesions described as congenital cutaneous skeletal hypophosphatemia syndrome. Here, we describe two patients with keratinocytic epidermal nevi, in one associated with a papular nevus spilus, who presented with distinct localized congenital fibro-osseous lesions in the lower leg, diagnosed on both radiology and histology as osteofibrous dysplasia, in the absence of hypophosphatemia or rickets, or significantly raised FGF23 levels but with distinct mosaic HRAS mutations.
View Article and Find Full Text PDFPurpose: Proteus syndrome arises as a result of a post-zygotic mosaic activating mutation in the AKT1 oncogene, causing a disproportionate overgrowth of affected tissues. A small number of ocular complications have been reported. We present the unique findings in a patient who had molecular confirmation of AKT1 mosaicism alongside fulfilling the clinical criteria for Proteus syndrome.
View Article and Find Full Text PDFRNA modifications play a fundamental role in cellular function. Pseudouridylation, the most abundant RNA modification, is catalyzed by the H/ACA small ribonucleoprotein (snoRNP) complex that shares four core proteins, dyskerin (DKC1), NOP10, NHP2, and GAR1. Mutations in , , or cause dyskeratosis congenita (DC), a disorder characterized by telomere attrition.
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