Abstract: We report a case of adolescent male who was admitted to hospital due to proteinuria with microscopic hematuria and hypertension. On admission,serum albumin was normal,but globulin was as low as 14 g/L. Serum IgG,IgM and IgA levels were low and peripheral blood CD19+ B cells were significantly decreased (8/μl,<2%).Whole exome sequencing indicated that the Xchromosome BTK gene had a missense mutation (C.82c>T,p.R28C).The patient was a hemizygote mutation and his mother who was a carrier of the BTK gene.Renal biopsy revealed membranoproliferative glomerulonephritis.The final diagnosis was Xlinked agammaglobulinemia complicated with MPGN.This is the first case reported in China.Proteinuria and hematuria improved after angiotensin Ⅱ receptor antagonist treatment.

Key words: X-linked agammaglobulinemia, BTK gene, membranoproliferative glomerulonephritis, genetic disorder