The HS cohort recruited to this study included mutations that produce defects in the membrane skeleton (SPTB; 15 to 30% of all HS cases) and those leading to a membrane-destabilizing effect (SLC4A1; 33% of all HS cases) (21, 23) (SI Appendix, Table S1). This evidence concerns the gene SLC4A1 and histiocytic sarcoma.