• Childhood Kidney Diseases
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• v.28 no.3
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• pp.124-130
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• 2024

Complement component 3 glomerulonephritis (C3GN) is a rare kidney disease characterized by complement dysregulation that results in prominent complement component 3 (C3) deposition in the kidneys. The clinical course of C3GN varies from mild hematuria to progressive chronic kidney disease. In most patients, C3GN is driven by acquired factors, namely, autoantibodies that target C3 or C5 convertases. Genetic variations in complement-related genes are less frequent. We report the case of a 9-year-old Korean boy who presented with microscopic hematuria and a persistently low C3 level and had biopsy findings of C3GN, with the presence of a C3 gene mutation: a frameshift mutation associated with C3 deficiency. However, the patient did not exhibit any other symptoms of complement deficiency. Direct DNA sequencing of his family members revealed the same genetic mutation in his father and older brother. This case report is significant because there are very few such reports worldwide concerning gene mutations related to C3 deficiency to be discovered in patients with C3GN. Explaining C3GN pathogenesis is challenging; therefore, additional research is required in the future.

• Clinical and Experimental Pediatrics
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• v.52 no.6
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• pp.721-724
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• 2009

Meningococcal infections can be associated with abnormalities of the complement system, which contains 5 terminal complement proteins. Furthermore, deficiencies in 1 of these 5, complement component 7 (C7), leads to the loss of complement lytic function, and affected patients show increased susceptibility to recurrent meningococcal meningitis and systemic Neisseria gonorrhoeae infection. In September 2003, an 11-year-old female patient presented at our outpatient department with high fever, lower leg pain, headache, and petechiaes. She rapidly progressed to coma but later achieved full recovery due to prompt treatment. Her final diagnosis was meningococcal sepsis and arthritis. Her elder brother also had a similar bacterial meningoencephalitis history, which encouraged us to perform analyses for complement component and gene mutations. Resultantly, both the brother and sister were found to have the same mutation in the C7 gene. Subsequently, vaccinations of the meningococcal vaccine meningococcal vaccine ($Menomune^{(R)}$) were administered. However, in September 2006, the brother expired due to acute micrococcus meningoencephalitis. At present, the 16-year-old female patient is healthy. Here, we report a Korean family with a hereditary C7 deficiency with susceptibility to meningococcal infections due to C7 gene mutation.