BACKGROUND Treatment of steroid-resistant nephrotic syndrome (SRNS) remains a challenge for paediatricians. SRNS accounts for 10~20% of childhood cases of nephrotic syndrome (NS). Individuals with SRNS overwhelmingly progress to chronic kidney disease (CKD) and end-stage kidney disease (ESRD). Genetic research is of great significance for diagnosis and treatment. More than 39 recessive or dominant genes have been found to cause human SRNS, including COQ2. COQ2 gene mutations not only cause primary coenzyme Q10 deficiency but also cause SRNS without extrarenal manifestations. The concept of COQ2 nephropathy has been proposed for a long time. Mutations in the COQ2 gene have rarely been reported. Worldwide, only 5 cases involving 4 families have been reported. CASE PRESENTATION We present the case of a 6-month-old girl with steroid-resistant glomerulopathy due to a COQ2 defect with no additional systemic symptoms. The patient was identified as a homozygote for the c.832 T > C (p. Cys278Arg) missense mutation and a single base homozygous mutation in ARSB gene in c.1213 + 1G > A. The father and mother were heterozygous mutation carriers in both COQ2 and ARSB, and her healthy sister was only a heterozygous mutation carrier in COQ2. In this case, hormone therapy was ineffective, and progressive deterioration of renal function occurred within 1 week after onset, leading to acute renal failure and eventual death. CONCLUSIONS We reported a consanguinity married family which had COQ2 and ARSB dual mutant. Kidney diseases caused by COQ2 gene mutations can manifest as SRNS, with poor prognosis. The C. 832 T > c (p.csc 278arg) is a new mutation site. Genetic assessment for children with steroid-resistant nephrotic syndrome, especially in infancy, is very important. Families with a clear family history should receive genetic counselling and prenatal examinations, and children without a family phenotype should also receive genetic screening as early as possible.

中文翻译：

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伴有COQ2和ARSB基因突变的近亲结婚所致婴儿的类固醇抗性肾病综合征：一例病例报告。

背景技术对类固醇抵抗性肾病综合征（SRNS）的治疗仍然是儿科医生的挑战。SRNS占儿童肾病综合征（NS）病例的10％至20％。患有SRNS的患者绝大多数会发展为慢性肾脏疾病（CKD）和终末期肾脏疾病（ESRD）。遗传研究对诊断和治疗具有重要意义。已经发现超过39个隐性或显性基因可导致人类SRNS，包括COQ2。COQ2基因突变不仅会导致原发性辅酶Q10缺乏症，而且还会导致无肾外表现的SRNS。COQ2肾病的概念已经提出了很长时间。很少有人报道过COQ2基因的突变。在全球范围内，仅报道了5起涉及4个家庭的病例。病例介绍我们介绍了一个因COQ2缺陷而没有其他全身症状的6个月大女孩患有类固醇耐药性肾小球病的病例。该患者被鉴定为c.832 T> C（p。Cys278Arg）错义突变的纯合子，以及c.1213 + 1G> A的ARSB基因的单碱基纯合突变。 COQ2和ARSB，以及她健康的妹妹只是COQ2中的杂合突变携带者。在这种情况下，激素治疗无效，发病后1周内肾功能逐渐恶化，导致急性肾衰竭并最终死亡。结论我们报道了一个血缘已婚的家庭，其具有COQ2和ARSB双重突变体。由COQ2基因突变引起的肾脏疾病可表现为SRNS，预后较差。C. 832 T> c（p.csc 278arg）是一个新的突变位点。对患有类固醇抵抗性肾病综合征的儿童进行遗传评估，尤其是在婴儿期，这一点非常重要。有明确家族史的家庭应接受遗传咨询和产前检查，没有家族表型的儿童也应尽早接受基因筛查。