Structural and Dynamic Analyses of Pathogenic Variants in PIK3R1 Reveal a Shared Mechanism Associated among Cancer, Undergrowth, and Overgrowth Syndromes.

The PI3K enzymes modify phospholipids to regulate cell growth and differentiation. Somatic variants in PI3K are recurrent in cancer and drive a proliferative phenotype. Somatic mosaicism of PIK3R1 and PIK3CA are associated with vascular anomalies and overgrowth syndromes. Germline PIK3R1 variants are associated with varying phenotypes, including immunodeficiency or facial dysmorphism with growth delay, lipoatrophy, and insulin resistance associated with SHORT syndrome. There has been limited study of the molecular mechanism to unify our understanding of how variants in PIK3R1 drive both undergrowth and overgrowth phenotypes. Thus, we compiled genomic variants from cancer and rare vascular anomalies and sought to interpret their effects using an unbiased physics-based simulation approach for the protein complex. We applied molecular dynamics simulations to mechanistically understand how genetic variants affect PIK3R1 and its interactions with PIK3CA. Notably, iSH2 genetic variants associated with undergrowth destabilize molecular interactions with the PIK3CA receptor binding domain in simulations, which is expected to decrease activity. On the other hand, overgrowth and cancer variants lead to loss of inhibitory interactions in simulations, which is expected to increase activity. We find that all disease variants display dysfunctions on either structural characteristics or intermolecular interaction energy. Thus, this comprehensive characterization of novel mosaic somatic variants associated with two opposing phenotypes has mechanistic importance and biomedical relevance and may aid in future therapeutic developments.

Methotrexate for inflammatory skin disease in pediatric patients: Consensus treatment guidelines.

Methotrexate (MTX) is a readily accessible drug, first used in 1948 and employed for a wide variety of indications since then. However, despite widespread off-label use, FDA labeling does not include approved indications for the use of MTX for many inflammatory skin diseases in pediatric patients, including morphea, psoriasis, atopic dermatitis, and alopecia areata, among others. Without published treatment guidelines, some clinicians may be hesitant to use MTX off-label, or uncomfortable prescribing MTX in this population. To address this unmet need, an expert consensus committee was convened to develop evidence- and consensus-based guidelines for use of MTX to treat pediatric inflammatory skin disease. Clinicians with experience and expertise in clinical research, drug development, and treating inflammatory skin disease in pediatric patients with MTX were recruited. Five committees were created based on major topic areas: (1) indications and contraindications, (2) dosing, (3) interactions with immunizations and medications, (4) adverse effects (potential for and management of), and (5) monitoring needs. Pertinent questions were generated and addressed by the relevant committee. The entire group participated in a modified Delphi process to establish agreement on recommendations for each question. The committee developed 46 evidence- and consensus-based recommendations, each with >70% agreement among members, across all five topics. These are presented in tables and text, along with a discussion of supporting literature, and level of evidence. These evidence- and consensus-based recommendations will support safe and effective use of MTX for the underserved population of pediatric patients who may benefit from this valuable, time-honored medication.

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.

Cutaneous mosaic RASopathies associated with rhabdomyosarcoma.

Variants in RAS are known drivers of certain pediatric blood and solid cancers, including brain tumors. Though most RAS-driven cancers are thought to occur sporadically, genetic syndromes caused by germline RAS variants portend a slightly higher risk of rhabdomyosarcoma (RMS) development. Three new cases and a review of the literature demonstrate that in rare cases, certain somatic RAS variants are associated with an increased risk of RMS and that RMS development may be heralded by the presence of concomitant RAS-driven birthmarks. Further prospective studies are needed to establish incidence and recommend appropriate monitoring guidelines for patients at risk.

Diversity in pediatric dermatology: A report from the Pediatric Dermatology Research Alliance and a call to action.

BACKGROUND/OBJECTIVES: The Pediatric Dermatology Research Alliance (PeDRA) connects pediatric dermatologists, trainees, basic scientists, allied health professionals, and patient advocates to improve the lives of children with skin disease through research. As a training pipeline for future pediatric dermatologists and steward of research in the field, PeDRA has a responsibility to examine its history and take actionable steps to diversify its membership, grant recipients, study leads, research priorities, and leadership. METHODS: In 2020, PeDRA formed an Equity, Diversity, and Inclusion Task Force to address this need. In an effort to assess PeDRA's past and plan for PeDRA's future, a review of PeDRA's membership, leadership, grant awardees, and research topics was conducted. RESULTS/CONCLUSIONS: Results demonstrated gaps in PeDRA's current operational efforts to diversify the pediatric dermatology workforce and identified areas for improvement. Recommendations are proposed as a call to action for the community.

Achieving equity and inclusion in pediatric dermatology research: Priorities and considerations.

As we increase our focus and energy on equity, diversity, and inclusion (EDI)-relevant research, we must consider the "what, why, and how" of our work. The goals of this paper are to highlight unique issues pediatric dermatologists face in providing equitable care, pose considerations when reporting data on race and ethnicity, and advocate for standardized classification of race and ethnicity in research.

Somatic PIK3R1 variation as a cause of vascular malformations and overgrowth.

PURPOSE: Somatic activating variants in the PI3K-AKT pathway cause vascular malformations with and without overgrowth. We previously reported an individual with capillary and lymphatic malformation harboring a pathogenic somatic variant in PIK3R1, which encodes three PI3K complex regulatory subunits. Here, we investigate PIK3R1 in a large cohort with vascular anomalies and identify an additional 16 individuals with somatic mosaic variants in PIK3R1. METHODS: Affected tissue from individuals with vascular lesions and overgrowth recruited from a multisite collaborative network was studied. Next-generation sequencing targeting coding regions of cell-signaling and cancer-associated genes was performed followed by assessment of variant pathogenicity. RESULTS: The phenotypic and variant spectrum associated with somatic variation in PIK3R1 is reported herein. Variants occurred in the inter-SH2 or N-terminal SH2 domains of all three PIK3R1 protein products. Phenotypic features overlapped those of the PIK3CA-related overgrowth spectrum (PROS). These overlapping features included mixed vascular malformations, sandal toe gap deformity with macrodactyly, lymphatic malformations, venous ectasias, and overgrowth of soft tissue or bone. CONCLUSION: Somatic PIK3R1 variants sharing attributes with cancer-associated variants cause complex vascular malformations and overgrowth. The PIK3R1-associated phenotypic spectrum overlaps with PROS. These data extend understanding of the diverse phenotypic spectrum attributable to genetic variation in the PI3K-AKT pathway.

Cutaneous reactions to pediatric cancer treatment part II: Targeted therapy.

Cancer remains a leading cause of morbidity and mortality among children. Targeted therapies may improve survivorship; however, unique side-effect profiles have also emerged with these novel therapies. Changes in hair, skin, and nails-termed dermatologic adverse events (AEs)-are among the most common sequelae and may result in interruption or discontinuation of therapy. Though dermatologic AEs have been detailed in adults, these findings are not well described in the pediatric population. We reviewed the literature to characterize dermatologic AEs to anticancer targeted therapies available as of July 2020 and summarized the spectrum of clinical findings as well as treatment recommendations for children. Dermatologic AEs are among the most common AEs reported in pediatric patients receiving targeted therapy, but morphologic and histologic descriptions are often lacking in current publications. Pediatric dermatologists are uniquely poised to recognize specific morphology of dermatologic AEs and make recommendations for prevention and treatment that may improve quality of life and enable ongoing cancer therapy.

Café au lait spots: When and how to pursue their genetic origins.

Café au lait spots are common birthmarks seen sporadically and in association with several genetic syndromes. Dermatologists are often asked to evaluate these birthmarks both by other physicians and by parents. In some cases, it is challenging to know when and how to pursue further evaluation. Diagnostic challenges may come in the form of the appearance of the individual lesions, areas and patterns of cutaneous involvement, and associated features (or lack thereof). In this review, we aim to clarify when and how to evaluate the child with multiple or patterned café au lait spots and to explain some emerging concepts in our understanding of the genetics of these lesions.

A sixteen-year single-center retrospective chart review of Spitz nevi and spitzoid neoplasms in pediatric patients.

BACKGROUND: Spitzoid neoplasms in pediatric patients pose an interesting challenge for clinicians. More data on the clinical, histologic, and molecular characteristics of these lesions are necessary to distinguish features that may portend recurrence or malignant behavior to help determine future treatment guidelines in pediatric patients. METHODS: Institutional Review Board approval was obtained from Children's Hospital of Wisconsin to conduct a retrospective analysis of spitzoid neoplasms. Patients with biopsied or excised spitzoid neoplasms between 01/01/2000 and 08/01/2016 were included. Pertinent clinical and histologic data were collected. Atypical, unusual, or diagnostically uncertain lesions were selected for re-review. RESULTS: 266 lesions from 264 patients were included. 243 were classified as benign (91.35%), 22 as atypical (8.27%), and 1 as spitzoid melanoma (0.38%). No clinical or histologic variables were found to be statistically significant between the benign Spitz, atypical Spitz, and spitzoid melanoma cohorts. No known deaths occurred. CONCLUSION: Our findings highlight the extreme variability of spitzoid neoplasms clinically and histologically. Importantly, this study demonstrates that the vast majority of spitzoid neoplasms in pediatric populations are benign and supports conservative management of spitzoid lesions in children.

Hamartomas and midline anomalies in association with infantile hemangiomas, PHACE, and LUMBAR syndromes.

BACKGROUND/OBJECTIVE: The pathogenesis of infantile hemangiomas (IH), PHACE, and LUMBAR syndromes remains unknown. We aim to describe histopathologic features of midline anomalies associated with IH, including patients with PHACE and LUMBAR syndromes. METHODS: A multicenter retrospective chart review was performed to identify patients with IH, PHACE, and LUMBAR syndrome with histopathologic specimens from sternal or midline anomalies. A total of 18 midline lesions from 13 patients were included. Out of 18, 14 midline lesions underwent both histopathologic and clinical review. Three hamartoma-like chin plaques and one supraumbilical raphe underwent only clinical review. RESULTS: All 13 patients had midline lesions and IH. Histopathologic diagnoses were as follows: rhabdomyomatous mesenchymal hamartoma (3), folliculosebaceous cystic hamartoma (1), fibroepithelial polyp (1), verrucous epidermal hyperplasia with vascular proliferation and fibroplasia (1), congenital midline cervical cleft (1), pericardium with fibrosis (1), fibrous components with increased collagen (1), atrophic skin/membrane (3), angiolipomatous mass with neural components (1), and lipomatous mass (1). Due to the retrospective nature of this study, it was not possible to obtain pathology slides for all midline lesions that had previously been biopsied or resected. We show clinically and histopathologically a new association between PHACE syndrome and rhabdomyomatous mesenchymal hamartoma (RMH), in addition to demonstrating the association between PHACE syndrome and chin hamartomas. We also display histopathologic findings seen in midline lesions resected from LUMBAR patients. CONCLUSION: Rhabdomyomatous mesenchymal hamartoma is thought to be related to aberrations of mesenchymal cells during development; therefore, this may provide clues to the pathogenesis of IH and related syndromes.

Natural history of PHACE syndrome: A survey of adults with PHACE.

BACKGROUND: Awareness of PHACE syndrome has increased; however, little information exists regarding its natural history, especially in patients over the age of 18. We aim to describe the natural history of PHACE to enhance clinical management and counseling of patients. METHODS: A cohort of patients ≥ 18 years was identified through the PHACE Syndrome Registry and a Vascular Anomalies Clinic Database. A cross-sectional survey was designed after a review of the literature by PHACE experts (IF, JP, DS). Questions were selected by consensus, and the survey was conducted using the Qualtrics platform and via in-person interviews. A 75% response rate was found. RESULTS: Eighteen adults-17 females and one transgender male-completed the survey. Respondents ranged in age from 18 to 59, with 24 being the mean age. Eighty-nine percent reported experiencing headaches, and 17% reported experiencing acute but transient symptoms mimicking acute ischemic stroke, later diagnosed as atypical migraines. Thirty-three percent reported hearing loss, and 67% endorsed dental issues. One patient experienced two arterial dissections. Three-fourths who attempted conception were successful, and none of their children had clinical features of PHACE. Because results were based on a retrospective survey, data captured were prone to recall bias and not objective. Results were limited by a small sample size. CONCLUSIONS: Health care providers should be aware of a possible increased risk of neurovascular complications, including atypical migraines mimicking transient ischemic attacks and arterial dissection, in adults with PHACE. Heritability has not been demonstrated, and future studies are needed to assess the risk of infertility.