RESUMO
To analyze a case of thin basement membrane nephropathy combined with juvenile idiopathic arthritis diagnosed in November 2017 in Children′s Hospital of Chongqing Medical University.A male patient with 7 years and 11 months old presented with swelling of bilateral interphalangeal joints and abnormal gait was diagnosed as juve-nile idiopathic arthritis.Urine examination revealed microscopic hematuria.Long-term follow-up after discharge showed recurrent joint symptoms and persistent microscopic hematuria.In February 2019, genetic testing showed the COL4A4 gene mutation (c.3479G>A p. G1160E). Through literature review, a case of rheumatoid arthritis complica-ted with Alport syndrome caused by the COL4A5 gene mutation c. 1351T>C (p.Cys451Arg) was previously reported.Both of 2 patients were diagnosed as collagen type Ⅳ-related renal diseases complicated with arthritis, and multiple joints involvement and renal involvement were detected.Excluding the influence of accidental factors and drugs, arthritis and some kidney diseases may have a co-pathogenesis under genetic background.The specific mechanism needs further exploration.This case report provided novel direction for the diagnosis and treatment of relevant diseases.