The pathogenic variants underlying the clinical diagnoses were identified as follows: SWS caused by a mosaic variant in GNAQ c.548G>A, p.(R183Q) in 17 patients; widespread CM caused by GNA11 c.547C>T, p.(R183C) in one; PPV-DM caused by GNAQ c.548G>A, p.(R183Q) in three and by GNA11 c.547C>T, p.(R183C) in another five. This evidence concerns the gene GNA11 and cutaneous mastocytosis.