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

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

METHOD: 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.

RESULT: 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.

CONCLUSION: 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.