M541L is the most common KIT polymorphism known (rs3822214) with a minor allele frequency of 0.08 in the gnomAD database (https://gnomad.broadinstitute.org/), is classified as benign/likely benign on ClinVar (www.ncbi.nlm.nih.gov/clinvar/), and has been described in the literature as a driver of pediatric mastocytosis [25]. Here, KIT is linked to mastocytosis.