HSCT is the only curative therapy for XLP and this therapy should be urgently considered.What is Known:• SAP and XIAP deficiencies share common clinical feature, HLH, whereas they also have their own specific manifestations.• IBD affects 25-30% of XIAP-deficient patients, which has been reported in other countries especially in European country and Japan.What is New:• This is the largest patient cohort study of XLP in China.• We firstly summarized the clinical features and outcomes of Chinese XIAP-deficient patients and found only 1 in 22 patients developed IBD and diet background may contribute to it; Asian SAP-deficient patients carrying SH2D1A R55X mutation were more prone to HLH.