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A CLINICOPATHOLOGICAL STUDY ON THIN GLOMERULAR BASEMENT MEMBRANE NEPHROPATHY (TGBMN) IN KOREAN CHILDREN

Jang HS¹, Koo JH¹, Kwak JS¹, Park YH², Chung WY³

¹ Kyungpook University Hospital, ² Youngnam University Hospital, Taegu, Korea, Inje University Hospital, Pusan, Korea

Objective: Present study is undertaken to determine the clincal charsteristics and outcome of TGBMN in Korean children and comparison has been made with Alport’s syndrome and other renal diseases accompanied by thin glomerular basement membrane (TGBM).

Methods: During the past 10 years, electron microscopic examination of biopsied renal tissue revealed diffuse thinning of glomerular basement membrane (TGBM) in 101 children. Out of these, 62 cases showed isolated finding of TGBM leading to the diagnosis of TGBMN, 11 cases were diagnosed as Alport’s syndrome, and in the remaining 28 cases, TGBM was associated with various other renal diseases.

Results: Age at onset of hematuria showed TGBMN occurring usually during school age children and Alport’s syndrome during preschool age children. Gross hematuria (GH) was seen more frequently than microscopic hematuria (MH) in Alport’s syndrome (GH:MH=5:6), and in TGBNM, MH was more frequent finding (GH:MH=8:52). Proteinuria was seen in 12 patients with TGBMN and out of these 4 cases were fulfilled as Nephrotic syndrome. Glomerular basement membrane thickness (nm, mean±SD) by EM examination was 172±37 in TGBMN and 194±17 in Alport’s syndrome (no statistical difference), and immunofluorolescent study showed C3, IgM and fibrinogen deposit in a few cases.

During follow up period (months, mean±SD; TGBMN; 27±21, Alport’s syndrome; 69±67) hematuria disappeared in 8 out of 62 TGBMN cases (11.9%) and renal impairment was not seen. Whereas in Alport’s syndrome, hematuria persisted in all cases and renal failure was seen in 3 cases. The most frequent renal diseases associated with TGBM were IgA nephropathy (14 cases) and MsPGN (9 cases).

Conclusion: TGBMN is an important cause of asymptomatic hematuria in children, escepecially during school age children with persistent microscopic hematuria. During follow up period, few children (11.9%) showed disappearance of hematuria and renal impairment was not observed, so that the prognosis of TGBMN seems to be good. However, more prolonged period of follow-up observation will be needed to determine the ultimate prognosis..