目的 分析同一家系男性X连锁Alport综合征患者临床表型的差异,结合文献探讨相同COL4A5基因突变的男性X连锁Alport综合征患者临床表型可能的影响因素.方法 收集同一家系2例男性(Ⅲ1和Ⅱ4)X连锁Alport综合征患者就诊及随访5年的临床资料.应用间接免疫荧光学方法检测皮肤基底膜α5(Ⅳ)链表达.应用反转录-聚合酶链反应直接测序和PCR直接测序方法分别从皮肤成纤维细胞mRNA和外周血基因组DNA水平检测COL4A5基因突变.结果 患者Ⅲ1就诊年龄为14岁,临床表现为镜下血尿,尿蛋白阴性;皮肤基底膜α5(Ⅳ)链染色阴性.随访5年期间,临床表现为持续性镜下血尿,尿蛋白阴性,尿微量白蛋白19.2～ 31.8 mg/L,未治疗.目前该患者19岁,尿检潜血+++,蛋白-;尿微量白蛋白19.20 mg/L;肾功能正常.患者Ⅱ4就诊年龄为29岁,于22岁发现血尿、蛋白尿,曾口服雷公藤治疗1年余,24岁出现“尿毒症”,行血液透析治疗,29岁(就诊前2个月)接受肾移植手术治疗,肾功能等指标良好.随访5年期间,尿常规及肾功能检查均正常.患者Ⅲ1和患者Ⅱ4均检测到COL4A5基因41外显子c.3650G＞ A(p.G1217D)突变.结论 同一家系具有相同COL4A5基因突变的男性X连锁Alport综合征患者在相似年龄段临床表型可截然不同,提示在判断疾病进展和预后时需注意,推测其机制可能是存在体细胞嵌合现象.%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.
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