[Features of clinical phenotype and genotype in Alport syndrome: a monocentric study]

To analyze the clinical features and gene mutation of Chinese children with Alport syndrome(AS).

From May 2011 to May 2014, clinical and pathological information gathered from 25 patients was retrospectively analyzed. COL4A5, COL4A4 and COL4A3 genes were analyzed using next-generation sequencing in these patients, and gene mutations of related family members were identified by Sanger method.

Of these 25 cases, 19(76%) had X-linked Alport syndromes (XL-AS), 6 had autosomal recessive Alport syndromes (AR-AS). Twenty five patients had an onset of hematuria and proteinuria and in 8 cases the disease was induced by upper respiratory tract infections. Hearing loss was present in 2 of 25 (8%) cases and ocular lesions in 1 of 25 (4%). Renal pathology showed that 16 of them had minimal change disease (MCD), 8 mesangial proliferative glomerulonephritis (MsPNG), 1 focal segmental glomerulo-sclerosis (FSGS). Extensive lamination and split of glomerular basement membrane (GBM) dense layers were found in 2 (8%) of 25 patients. Twenty one of 25 patients (84%) showed abnormal renal α-chain distribution. COL4A5, COL4A4 and COL4A3 genes of 25 patients (23 families) were analyzed and 24 pathogenic mutations were identified: 18 in COL4A5, 1 in COL4A3 and 5 in COL4A4. It was observed that 13 patients inherited the mutation from the mother, 3 patients inherited from the father, 2 patients inherited 1 mutation from the mother and another mutation from the father, and 7 patients carried the novel mutations.

XL is the main inherited type in AS. Most of patients showed MCD and MsPNG in renal biopsy. This research examined 24 mutations and 16 mutations were not reported previously.