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Some studies suggest that the inactivation of the Ras-MAPK pathway in trophoblast cells can lead to recurrent abortion, but the molecular mechanism underlying the inactivation of this pathway in trophoblast cells is still unclear. This study aimed to explore the relationship between the mechanism of abnormal activation of RASA1, a regulatory protein of the Ras-MAPK pathway, and unexplained recurrent spontaneous abortion. RT-qPCR was used to detect the transcription levels of RASA1 gene. Immunohistochemistry and Western blot were used to detect the expression levels of the RASA1, Raf and MEK proteins. CCK-8, TUNEL and Transwell assays were used to detect the proliferative, apoptotic, and invasive capacities of HTR-8/SVneo cells. ChIP assays were used to detect the enrichment of H3K27me3 in RASA1 gene promoter. Abortion villi experiments showed that the enrichment of H3K27me3 in the RASA1 gene promoter was reduced, and that both RASA1 gene transcription and RASA1 protein expression were increased. Cell experiments confirmed that RASA1 could decrease the phosphorylated Raf and MEK proteins, inhibit the proliferation and invasion ability, and promote the apoptosis ability of HTR-8/SVneo cells. It was also found that the proliferation and invasion ability as well as the Ras-MAPK pathway activity of HTR-8/SVneo cells were inhibited when treated with histone methyltransferase inhibitor DZNep. RASA1 gene was abnormally activated in unexplained recurrent spontaneous abortion villi due to the decreased enrichment of H3K27me3 in the gene promoter. High expression of RASA1 could inhibit the activity of the Ras-MAPK pathway, and thus inhibit the proliferation and invasion ability of trophoblast cells.

Background: The prevalence of capillary malformations, also known as port-wine stains (PWS), is 0.3%. Familial segregation can occur. The capillary malformation–arteriovenous malformation (CM-AVM) phenotype is caused by mutations in the RASA1 gene. In PWS familial cases, the inheritance is considered to be autosomal dominant with variable penetrance. Objective: Investigation of the heredity of PWS among patients who attended the vascular anomaly section at the Department of Dermatology in Malmoe, Southern Sweden, between 1993 and 2004 and to study the involvement of the RASA1 gene in patients with a positive family history of PWS. Subjects and methods: A total of 254 patients were examined and given a questionnaire regarding family history of PWS. The first group of 175 patients (109 females and 66 males) reported a negative family history. The other group of 65 patients (46 females and 19 males) reported a positive family history (50% parents or brothers and sisters). Results: The heredity of PWS was 27% (65/240). Twenty-one patients with a positive family history and relatives had no CM-AVM phenotype for mutations in the RASA1 gene. Conclusion: PWS may have a stronger heredity component than it was reported earlier and inheritance should be considered when counseling a patient. RASA1 mutations do not explain the PWS in our patients.

Capillary malformation–arteriovenous malformation (CM–AVM) is a newly recognized clinical entity caused by mutation of the RASA1 gene, which encodes p120-RasGAP. Here we describe, for the first time, a patient with CM–AVM presenting during the late stages of pregnancy with pulmonary “capillary level” microvascular shunt, worsening cutaneous capillary malformations, and gross fluid overload. Sequencing revealed a novel mutation of the RASA1 gene involving a frameshift mutation in the RASGAP domain of RASA1. This report extends our current genetic and clinical understanding of CM–AVM. © 2013 Wiley Periodicals, Inc.

Hereditary capillary malformations are known to be caused by mutations in the RASA1 gene. The associated phenotype is still subject of debate. The purpose of this study was to conduct a RASA1 mutation analysis in the family that led to the initial discovery of the 5q locus, and to delineate the associated phenotype. A novel truncating mutation was identified in all clinically affected individuals and in none of the unaffected members. The associated phenotype was widely variable; all individuals had multifocal CM with at least one area of high flow. Various additional features were observed, some previously reported and others novel, including limb overgrowth, varicosities, possible lymphatic malformations, localized hyperhidrosis and exercise induced redness. The cause of this wide intramutational phenotypic variability remains to be elucidated. (C) 2012 Published by Elsevier Masson SAS