[Clinical and pathological study of 47 cases with Alport syndrome]

To analyze the clinical and pathological features of children with Alport syndrome (AS).

A series of 47 patients with AS from unrelated families hospitalized from Jan. 1990 to Jan. 2007 were involved in this study. The clinical and histopathological data were collected and analyzed.

Of the 47 cases, 32 were male and 15 female, M/F: 2.1:1. The patient's age ranged from 15 months to 13 years, mean 9 years. Thirty-nine of the 47 cases had positive family history, X-linked dominant inheritance AS was diagnosed in 37 cases, autosomal recessive inheritance AS in 2 cases. Gross hematuria or microscopic hematuria were found in 59.3% of the cases as the first manifestations, while 29.8% showed edema or proteinuria. The major clinical manifestations were isolated hematuria (23.4%), hematuria and proteinuria (36.2%), nephrotic syndrome (29.8%), and renal failure (10.6%). Hematuria and proteinuria existed in all the cases, while only 7 to 13 years children had nephrotic syndrome and renal failure. Of the 47 patients, 33 (70.2%) showed mesangial proliferative glomerulonephritis (MsPGN) under the light microscope, 13 (27.6%) focal segmental glomerulosclerosis (FSGS), 1 (2.1%) membrane proliferative glomerulonephritis (MPGN). For immunofluorescence, there was IgM (40.4%) as the dominant deposition in 19 patients, IgA in 9 (19.1%), IgG in 9 (19.1%), and 10 (21.4%) were negative. Thirty-nine cases showed typical glomerular basement membrane (GBM) pathological changes under electron microscope, while thin basement membrane in 8 cases; 46 showed abnormal skin and/or renal alpha-chain distribution.

For Alport syndrome, number of male patients was higher than that of female patients. There was a significant difference among different age groups. Hematuria might be present throughout the course, while urine protein increases gradually. MsPGN was the dominant pathological change. The GBM pathological changes in younger children is not typical, so the immunofluorescence test of alpha-chain in collagen IV should be used as an important diagnostic method.