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Capillary malformation-arteriovenous malformation (CM-AVM) is an autosomal dominant inherited rare type of vascular malformation encountered in a neonate and first described in 2003. It has been reported in association with heterozygous mutations in the RASA1 gene, which encodes the protein RASp21. In 2010, a German doctor proposed rhodoid nevus as a name for this type of capillary malformation; in ancient Greek, rhodoides means "rose-like" or "rose-colored." Accordingly, CM-AVM could also be called "rhodoid nevus syndrome." We report this case as its very challenging diagnosis with its further differentials and its association with thrombocytopenia.

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 blood and lymphatic vessel (LV) disorder that is caused by inherited inactivating mutations of the RASA1 gene, which encodes p120 RasGAP (RASA1), a negative regulator of the Ras small GTP-binding protein. How RASA1 mutations lead to the LV leakage defects that occur in CM-AVM is not understood. Here, we report that disruption of the Rasa1 gene in adult mice resulted in loss of LV endothelial cells (LECs) specifically from the leaflets of intraluminal valves in collecting LVs. As a result, valves were unable to prevent fluid backflow and the vessels were ineffective pumps. Furthermore, disruption of Rasa1 in midgestation resulted in LEC apoptosis in developing LV valves and consequently failed LV valvulogenesis. Similar phenotypes were observed in induced RASA1-deficient adult mice and embryos expressing a catalytically inactive RASA1R780Q mutation. Thus, RASA1 catalytic activity is essential for the function and development of LV valves. These data provide a partial explanation for LV leakage defects and potentially other LV abnormalities observed in CM-AVM.

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

p120 Ras GTPase-activating protein (RasGAP) encoded by the rasa1 gene in mice is a prototypical member of the RasGAP family of proteins involved in negative-regulation of the p21 Ras proto-oncogene. RasGAP has been implicated in signal transduction through a number of cell surface receptors. In humans, inactivating mutations in the coding region of the RASA1 gene cause capillary malformation arteriovenous malformation. In mice, generalized disruption of the rasa1 gene results in early embryonic lethality associated with defective vasculogenesis and increased apoptosis of neuronal cells. The early lethality in this mouse model precludes its use to further study the importance of RasGAP as a regulator of cell function. Therefore, to circumvent this problem, we have generated a conditional rasa1 knockout mouse. In this mouse, an exon that encodes a part of the RasGAP protein essential for catalytic activity has been flanked by loxP recognition sites. With the use of different constitutive and inducible Cre transgenic mouse lines, we show that deletion of this exon from the rasa1 locus results in effective loss of expression of catalytically-active RasGAP from a variety of adult tissues. The conditional rasa1 mouse will be useful for the analysis of the role of RasGAP in mature cell types.

Melanoma shows frequent Ras-Raf-MAPK pathway activation via frequent mutations in NRAS and BRAF. Novel mutations in other components of this pathway such as MEK1, MEK2, MAP3K5, and MAP3K9 have been reported recently by high-throughput sequencing efforts. In addition, NF1 (neurofibromatosis type 1), one of the Ras GTPase activating proteins (RasGAPs), has been shown to be mutated or suppressed in melanoma. However, importance of other RasGAPs has not been addressed in melanoma. To obtain a comprehensive view of melanoma genomes, we conducted whole genome sequencing (WGS) of 15 metastatic melanomas and matched normal PBMC genomes from 13 melanoma patients. All melanoma genomes from these 13 patients contained at least one mutation in genes of Ras-Raf-MAPK pathway (MAPK1, MAP3K1, MAP4K2, MAP3K14, NRAS, and BRAF). Our whole genome analyses also identified two novel somatic missense mutations (p.Tyr472His and p.Leu481Phe) in or around the PH domain in RASA1 gene. RASA1 (RAS p21 protein activator (GTPase activating protein) 1, also called as p120RasGAP) is a GTPase activation protein that negatively regulates Ras by catalyzing the hydrolysis of active Ras-GTP to inactive Ras-GDP. In this study, we addressed possible roles of RASA1 in melanoma tumorigenesis. To determine RASA1 level in melanocytic lesions, immunohistochemical analysis of RASA1 on human melanoma tissue microarray (TMA) containing nevi (n=34), primary melanomas (n=63), lymph node metastasis (n=35), and distal metastasis (n=29) was performed. This analysis has shown the inverse correlation of RASA1 expression to melanoma progression. Functionally, ectopic expression of RASA1 mutant increased soft-agar colony formation and tumor growth while that of wild-type RASA1 decreased. shRNA-mediated knock down of RASA1 promoted soft-agar colony formation and invasion of melanocytes and melanoma cells with BRAF mutation as a consequence of the elevated Ras activity. Here, we established the functional significance of novel somatic missense mutations in RASA1 identified in our WGS study. Collectively, these data implicated that RASA1 inactivation by loss of expression and/or mutation may promote melanoma tumorigenesis. Citation Format: Hyeran Sung, Li Ding, Krishna L. Kanchi, Jane L. Messina, Vernon K. Sondak, Mulé J. James, Richard K. Wilson, Jeffrey S. Weber, Minjung Kim. RASA1 alteration promotes melanoma tumorigenesis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 442. doi:10.1158/1538-7445.AM2014-442

To the Editor: The identification of underlying causal genes in familial forms of cerebrovascular malformations allows the dissection of an increasing number of these disorders at the molecular level. In recent years, mutations in CCM1/KRIT1 , CCM2/MGC4607 , and CCM3/PDCD10 have been found to cause autosomal dominantly inherited cerebral cavernous malformations (CCM1, CCM2, and CCM3). Clinical penetrance appears to differ between the 3 CCM subtypes, but larger clinical studies are required to confirm this observation. A subset of patients with cerebral arteriovenous malformations also shows cutaneous capillary malformations attributable to mutations in the RASA1 gene or is affected by hereditary hemorrhagic telangiectasias (HHT) resulting from mutations in the endoglin gene ( ENG , HHT1), the activin receptor-like kinase1 gene …