Analysis of phenotypic heterogeneity of male patients with X-linked Alport syndrome from one family / 中华实用儿科临床杂志

ABSTRACT

Objective In this study,the phenotype heterogeneity of 2 male patients with X-linked Alport syndrome from one family was analyzed and the likely reasons were discussed by reviewing the literature.Methods The clinical data at the time of diagnosis and during 5 years follow-up of 2-male patients with X-linked Alport syndrome from one family were collected.The α5 (Ⅳ) chain expression in the epidermal basement membrane was detected by indirect immunofluorescence method.COL4A5 gene mutations in skin fibroblasts and genomic DNA were detected by using reverse transcription polymerase chain reaction and direct sequencing and PCR sequencing methods from skin fibroblasts and genomic DNA,respectively.Results The diagnostic age of patient Ⅲ 1 was 14 years old.He had only microscopic hematuria,and proteinuria was negative.A negative α5 (Ⅳ) chain staining pattern was detected in his epidermal basement membrane.After 5 years follow-up without drug treatment,he was 19 years old,had persistent microscopic hematuria and normal renal function.The urinary microalbumin was 19.2-31.8 mg/L.The diagnosis age of patient Ⅱ 4 was 29 years old.The hematuria and proteinuria were found at 22 years old.He was treated with tripterygium wilfordii for 1 year.His disease progressed to an end stage of renal disease and he received hemodialysis therapy at 24 years old.He had the renal transplantation surgery at 29 years old,just 2 months before he came to hospital.And his renal function was restored.After 5 years follow-up,his urine examination and renal function were normal.Both patients had a missense mutation c.3650G ＞ A(p.G1217D) in exon 41 in COL4A5 gene.Conclusions The different phenotypes of 2 male patients from one family with X-linked Alport syndrome were reported.The most possible reason for this is somatic mosaic variants in COL4A5 gene based on literature review.Physicians should be alert to phenotype heterogeneity in male X-linked Alport syndrome despite having the same gene mutation.