SLC29A3 and type 1 diabetes mellitus: Pathogenic variants in SLC29A3 cause an autosomal, recessively inherited, autoinflammatory, multisystem disorder (Online Mendelian Inheritance in Man #602782), A number of conditions, including, inter alia, H syndrome, histiocytosis-lymphadenopathy plus syndrome, and pigmented hypertrichosis with insulin-dependent diabetes mellitus, previously believed to be distinct disorders, have recently been grouped within the same disease spectrum known as SLC29A3 spectrum disorder (1, 2).