Arslanoglu Aydin Elif, Ceylaner Serdar, Baglan Esra, Bagrul Ilknur, Kocamaz Nesibe Gokce, Ozdel Semanur
Department of Pediatric Rheumatology, Ankara Etlik City Hospital, Ankara, Turkey.
Department of Genetics, Intergen Genetics Centre, Ankara, Turkey.
Clin Rheumatol. 2025 Mar;44(3):1355-1365. doi: 10.1007/s10067-025-07333-y. Epub 2025 Jan 22.
Monogenic lupus is an extremely rare clinical condition in children. Defects in the complement pathway are the most common causes of monogenic lupus. C1qC deficiency is one of the defects in this pathway and is even rarer. Herein, we present two cases of monogenic lupus diagnosed with C1qC deficiency in siblings. In addition, a literature search was conducted for articles on monogenic lupus due to C1qC deficiency. We found 14 articles. Our literature search identified 17 paediatric patients with monogenic lupus associated with C1qC deficiency. 10 (58%) of the reported patients were female. The median age at diagnosis of patients in the literature was 3 years. Mucocutaneous involvement was remarkable in all cases of C1qC deficiency. Joint involvement was reported in about half of the cases. Approximately half of the reported cases has suffered from recurrent infections. 38% of the cases have had CNS involvement and 25% of these had nephritis. While both of our patients had mucocutaneous involvement, one of our patients had recurrent EBV infection. ANA was positive, anti-dsDNA was negative, C3-C4 levels were normal in almost all cases in the reported cases. The anti-Sm and anti-SSA positivities of these cases were also remarkable. These laboratory findings were similar in our patients. The G34R mutation of the C1qC gene is the most common genetic defect identified to date. We found a GRCh38/Hg38 1p36.12 homozygous deletion in the C1qC gene in both of our patients. It is necessary to investigate the causes of monogenic lupus in patients with early-onset lupus, history of consanguineous marriages, and antibody positivity.
单基因狼疮在儿童中是一种极其罕见的临床病症。补体途径缺陷是单基因狼疮最常见的病因。C1qC缺乏是该途径的缺陷之一，更为罕见。在此，我们报告两例在同胞中诊断为C1qC缺乏的单基因狼疮病例。此外，还对关于C1qC缺乏导致的单基因狼疮的文章进行了文献检索。我们找到了14篇文章。我们的文献检索确定了17例与C1qC缺乏相关的单基因狼疮儿科患者。报告的患者中有10例（58%）为女性。文献中患者的诊断中位年龄为3岁。在所有C1qC缺乏的病例中，皮肤黏膜受累都很明显。约一半的病例报告有关节受累。约一半的报告病例曾反复感染。38%的病例有中枢神经系统受累，其中25%有肾炎。我们的两名患者都有皮肤黏膜受累，其中一名患者有反复的EB病毒感染。在报告的病例中，几乎所有病例的抗核抗体呈阳性，抗双链DNA呈阴性，C3 - C4水平正常。这些病例的抗Sm和抗SSA阳性也很显著。我们的患者的这些实验室检查结果相似。C1qC基因的G34R突变是迄今为止确定的最常见的基因缺陷。我们在两名患者的C1qC基因中都发现了GRCh38/Hg38 1p36.12纯合缺失。有必要对早发性狼疮、近亲结婚史和抗体阳性的患者调查单基因狼疮的病因。
