Table 1.

Summary of Molecular Genetic Testing Used in RASA1-Related Disorders

Gene 1 Test MethodMutations Detected 2Mutation Detection Frequency by Test Method 3
RASA1Sequence analysis 4Sequence variantsAbout 70% 5
Deletion/duplication analysis 6Exon(s)or the entire geneUnknown 7

See Molecular Genetics for information on allelic variants.


The ability of the test method used to detect a mutation that is present in the indicated gene


Examples of mutations detected by sequence analysis may include small intragenic deletions/insertions and missense, nonsense, and splice site mutations; typically, exonic or whole-gene deletions/duplications are not detected. For issues to consider in interpretation of sequence analysis results, click here.


Extrapolated from data obtained from two large studies that used denaturing high-performance liquid chromatography (DHPLC) mutation scanning [Revencu et al 2008, Revencu et al 2013a]. A RASA1 mutation was identified in 44 (78%) of 56 probands and 68 (68%) of 100 probands with multifocal CMs with or without additional vascular malformations [Revencu et al 2008]. A RASA1 mutation was identified in 13 (81%) of 16 probands with PKWS with multifocal CMs [Revencu et al 2008]. Note: (1) Sequence analysis and mutation scanning of the entire gene can have similar mutation detection frequencies; however, mutation detection rates for mutation scanning may vary considerably between laboratories depending on the specific protocol used. (2) Mutation detection frequency is lower in clinical cases when compared to well-characterized research study groups because patient selection criteria are not likely to be as strict in clinical settings. One study found mutation in 10 (39%) of 26 probands with CMs [Wooderchak-Donahue et al 2012].


Testing that identifies deletions/duplications not readily detectable by sequence analysis of the coding and flanking intronic regions of genomic DNA; included in the variety of methods that may be used are: quantitative PCR, long-range PCR, multiplex ligation-dependent probe amplification (MLPA), and chromosomal microarray (CMA) that includes this gene/chromosome segment.


A patient with a large AVM on the face was found to carry a deletion of exons 21-25 [unpublished data]. One patient with 3.1-Mb microdeletion on the 5q14.3q15 region including RASA1 and four other genes has been reported [Carr et al 2011]. This patient has multifocal CMs and severe developmental delay associated with MEF2C haploinsufficiency. Carr et al [2011] reviewed four other individuals previously reported with simultaneous deletions of RASA1 and MEF2C, but capillary malformations were not reported in these individuals.

From: RASA1-Related Disorders

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