Genetic mutations and phenotype characteristics in peripheral vascular malformations: A systematic review

Vascular malformations (VMs) are clinically diverse with regard to the vessel type, anatomical location, tissue involvement and size. Consequently, symptoms and disease impact differ significantly. Diverse causative mutations in more and more genes are discovered and play a major role in the development of VMs. However, the relationship between the underlying causative mutations and the highly variable phenotype of VMs is not yet fully understood. In this systematic review, we aimed to provide an overview of known causative mutations in genes in VMs and discuss associations between the causative mutations and clinical phenotypes. PubMed and EMBASE libraries were systematically searched on November 9th, 2022 for randomized controlled trials and observational studies reporting causative mutations in at least five patients with peripheral venous, lymphatic, arteriovenous and combined malformations. Study quality was assessed with the Newcastle-Ottawa Scale. Data were extracted on patient and VM characteristics, molecular sequencing method and results of molecular analysis. In total, 5667 articles were found of which 69 studies were included, reporting molecular analysis in a total of 4261 patients and 1686 (40%) patients with peripheral VMs a causative mutation was detected. In conclusion, this systematic review provides a comprehensive overview of causative germline and somatic mutations in various genes and associated phenotypes in peripheral VMs. With these findings, we attempt to better understand how the underlying causative mutations in various genes contribute to the highly variable clinical characteristics of VMs. Our study shows that some causative mutations lead to a uniform phenotype, while other causal variants lead to more varying phenotypes. By contrast, distinct causative mutations may lead to similar phenotypes and result in almost indistinguishable VMs. VMs are currently classified based on clinical and histopathology features, however, the findings of this systematic review suggest a larger role for genotype in current diagnostics and classification.

Development of a condition-specific patient-reported outcome measure for measuring symptoms and appearance in vascular malformations: the OVAMA questionnaire

Background

The symptoms and appearance of vascular malformations can severely harm a patient’s quality of life. The aim of treatment of vascular malformations generally is to improve condition‐specific symptoms and/or appearance. Therefore, it is highly important to start testing treatment effects in clinical studies from the patient’s perspective.

Objectives

To develop a patient‐reported outcome measure for measuring symptoms and appearance in patients with vascular malformations.

Methods

A first draft of the patient‐reported outcome measure was based on the previously internationally developed core outcome set. The qualitative part of this study involved interviews with 14 patients, which led to a second draft. The second draft was field tested cross‐sectionally, after which groups of items were evaluated for adequate internal consistency (Cronbach’s alpha > 0·7) to form composite scores. Construct validity was evaluated by testing 13 predefined hypotheses on known‐group differences.

Results

The patient interviews ensured adequate content validity and resulted in a general symptom scale with six items, a head and neck symptom scale with eight items, and an appearance scale with nine items. Cronbach’s alpha was adequate for two composite scores: a general symptom score (0·88) and an appearance score (0·85). Ten out of 13 hypotheses on known‐group differences were confirmed, confirming adequate construct validity.

Conclusions

With the development of the OVAMA questionnaire, outcomes of patients with vascular malformations can now be evaluated from the patient’s perspective. This may help improve the development of evidence‐based treatments and the overall care for patients with vascular malformations.

What is already known about this topic?

The symptoms and appearance of vascular malformations may severely impact the patient’s physical, mental and social functioning.

Condition‐specific symptoms and appearance are the main drivers for treatment of vascular malformations.

Symptoms and appearance were determined to be core outcome domains and should be measured in all clinical research on vascular malformations.

No instrument exists for measuring patient‐reported symptoms and appearance problems in vascular malformations.

Vascular malformation research is hampered by heterogeneity in outcome measures.

What does this study add?

With this study, a condition‐specific patient‐reported outcome measure was developed for measuring symptoms and appearance in patients with vascular malformations: the OVAMA questionnaire.

This study confirms adequate content and construct validity.

What are the clinical implications of this work?

The problems that matter most to patients with vascular malformations can now be evaluated from the patient’s perspective.

Treatments can be evaluated and compared for effects on these core outcome domains.

This study is a big step in tackling current heterogeneity in outcome measures.

Clinically distinct groups can be determined based on disease severity.

The many applications of the OVAMA questionnaire may significantly improve research and, ultimately, the care for patients with vascular malformations.

Linked Comment: J. Tan. Br J Dermatol 2021; 185:695–696.