SLC4A1 and histiocytic sarcoma: Rare homozygous mutations of the SLC4A1 gene have been revealed, including the Coimbra mutation (Val488Met), which causes an extremely severe form of HS, associated with impaired renal anion metabolism and kidney damage (distal renal tubular acidosis, DRTA) (Delaunay, 2007; Eber and Lux, 2004; Wang et al., 2021).