目的: 通过分析1例胱氨酸尿症家系，探讨胱氨酸尿症的临床特征、诊治要点及遗传因素。方法: 回顾分析1例胱氨酸尿症家系病例资料，先证者为28岁男性。通过尿沉渣镜检、能谱CT测定先证者结石成分，提取先证者及家系成员外周血DNA样本，利用目标序列捕获高通量测序技术筛查突变基因。结果: 该家系先证者首诊于15岁。主要临床表现为复发性左侧泌尿道结石合并蛋白尿，其母亲主要表现为蛋白尿，父亲无肾脏受累症状。测序结果示先证者存在溶质载体家族3成员1（solute carrier family 3, member 1，SLC3A1）基因复合杂合突变，其中包括移码突变NM_000341:exon3:c.703delG（母亲为该杂合突变携带者）及错义突变NM_000341:exon8:c.1366C>T（父亲为该杂合突变携带者）。两突变均判定为疑似致病性变异。先证者有多次输尿管镜取石术史，尿沉渣镜检中可找到特异性胱氨酸六边形晶体，能谱CT结石成分测定为L-胱氨酸。先证者确诊为胱氨酸尿症后，予碱化尿液、降蛋白尿等治疗，目前病情稳定。结论: 尿沉渣镜检中找到六边形晶体是胱氨酸尿症的特异性诊断手段，胱氨酸能谱CT可无创诊断胱氨酸结石。对起病年龄小的复发性结石患者应高度怀疑遗传疾病，基因检测是胱氨酸尿症的病因诊断方式。

Objective To explore the clinical features, diagnosis and treatment points and genetic factors of cystinuria by analyzing a family with cystinuria. Methods The proband was a 28-year-old male, and the data of the family with cystinuria was retrospectively analyzed. The stone composition of the proband was determined by urine sediment microscopy, energy spectrum CT and infrared spectroscopy. The peripheral blood DNA samples of the proband and family members were extracted and captured by the target sequence. High-throughput sequencing technology was used to screen mutant genes, and the progress of diagnosis and treatment of cystinuria was discussed referring to literatures. Results The proband in this family was firstly diagnosed at 15 years old. His main clinical manifestation was recurrent left urinary tract calculi combined with proteinuria. The mother’s main manifestation was proteinuria, and the father had no symptoms related to kidney. The sequencing results showed that the proband had a compound heterozygous mutation in the solute carrier family 3, member 1(SLC3A1) gene, including the frameshift mutation NM_000341:exon3:c.703delG ( mother was the carrier of the heterozygous mutation) and missense mutation NM_000341:exon8:c.1366C>T (father is a carrier of the heterozygous mutation). According to American College of Medical Genetics and Genomics(ACMG) guidelines, both mutations were classified as suspected pathogenic variants. The proband had a history of multiple ureteroscopic lithotripsy, and specific hexagonal crystals could be found in urine sedimentary mirror examination and the stone composition was determined to be L-cystine by spectrum CT. After being diagnoses as cystinuria, the proband was treated with alkalization of urine and proteinuria, and his current condition was stable. Conclusions A specific diagnostic method for cystinuria is to find hexagonal crystals in urine sediment microscopy. Spectrum CT can be applied to diagnose cystine stones non-invasively. Genetic disease should be strongly considered in the patients with recurrent stones at young age, and genetic testing can be used as etiological diagnosis method for cystinuria.