Features of gene mutation and clinical phenotype in Alport syndrome / 医学研究生学报

ABSTRACT

Objective The article was to analyze the features of gene mutation and clinical phenotype in Alport syndrome. Methods Next-generation sequencing was applied to capture the exons of COL4A3, COL4A4, COL4A5 genes in 30 cases of children with suspected or confirmed diagnosis of Alport syndrome and Sanger method was used to identify gene mutations of related family mem-bers.Provean database was applied in protein function prediction.We collected and analyzed clinical data of AS patients on the basis of gene mutation. Results All 30 children were diagnosed with AS by gene sequencing, among whom 4 boys were autosomal reces-sive inheritance, 16 boys and 10 girls were X-linked Alport syndrome.Next-generation sequencing detected 35 different gene mutations of COL4A3, COL4A4, COL4A5, including 19 missense mutations, 2 synonymous mutations, 4 splice-site mutations, 3 truncating mu-tations, 2 insertion mutations, 4 deletion mutations and 1 compound mutations.It was observed by Sanger sequencing that 20 mutations were inherited from the mother, 8 from the father, homozygous mutation in 1 propositus from the parents respectively, 8 novel mutations and 1 with unidentified source.All the 30 children had an onset of hematuria or proteinuria, 17 cases had a positive family history, 1 case had hearing loss, and no pathogenesis or renal insufficiency was found in the children.Renal biopsy was performed on 23 children, 13 minimal change disease ( MCD) and 10 mesangial proliferative glo-merulonephritis ( MsPNG) by light microscope.Extensive lamination and split of glomerular basement membrane dense layers were found in 9 children by electron microscope. Conclusion XLAS ac-counts for most AS patients and missense mutation is the main type in pathogenic mutations.Altogether, 31 mutations without disease notification were found.Most of children showed MCD in renal biopsy, with atypical electron microscope manifestations and rare extra renal manifestations.