Nefropatia por C1q esporádica e Familiar
Data
2023-08-30
Autores
Pereira, Maria Eduarda Vilanova da Costa 
Orientadores
Kirztajn, Gianna Mastroianni
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
INTRODUÇÃO: A evolução do conhecimento sobre o sistema do complemento
resultou em novas classificações das glomerulopatias já existentes e na identificação
de novas entidades. A nefropatia por C1q (NC1q) é uma doença rara, encontrada
em 0,21 a 2% das biópsias renais. Suas manifestações anatomopatológicas são
variáveis: de podocitopatias a formas proliferativas. Sua resposta à
imunossupressão é heterogênea, com padrão comum de resistência a corticoide. A
doença foi descrita em 1985, porém ainda pouco se sabe sobre sua fisiopatogenia e
história natural. Casos de apresentação familiar da doença nos levam a questionar
uma possível etiologia genética. OBJETIVOS: os objetivos primários foram:
descrever as características clínicas, laboratoriais e histopatológicas dos casos de
NC1q acompanhados no Setor de Glomerulopatias da UNIFESP; e identificar
possíveis mutações genéticas associadas à doença. MÉTODOS: estudo
observacional retrospectivo de centro único envolvendo avaliação clínico-laboratorial
de todos os casos-índice e sequenciamento do exoma de parte dos pacientes com
diagnóstico anatomopatológico de NC1q. RESULTADOS: cinco pacientes foram
diagnosticados com NC1q, com idades de apresentação entre 15-45 anos. O
período de seguimento variou de 3 a 16 anos. A maioria era do sexo feminino e
apresentou padrão de glomerulosclerose segmentar e focal na análise por
microscopia óptica da biópsia renal. Apenas um caso cursou com padrão
anatomopatológico de doença de lesões mínimas; esse teve melhor resposta à
imunossupressão e evolução de função renal. Os demais apresentaram perda
significativa de taxa de filtração glomerular. Dos cinco pacientes, três apresentavam
história familiar de doença renal crônica de causa indeterminada. Um dos três
pacientes submetidos à avalição do exoma apresentou mutação no gene TP53RK,
que codifica a proteína reguladora da quinase TP53. DISCUSSÃO: O C1q é o
componente inicial da via clássica do complemento e desempenha papel
fundamental na imunidade. Não está claro o mecanismo de deposição e lesão
glomerular na NC1q, mas alterações estruturais glomerulares, infecções e
desregulação da cascata do complemento vêm sendo considerados. O gene
TP53RK está envolvido no controle da transcrição gênica. Suas mutações foram
associadas a síndrome neurorenal caracterizada por síndrome nefrótica córticoresistente
e redução de sobrevida podocitária, não havendo relato prévio de
associação com a NC1q. CONCLUSÃO: a NC1q é doença rara que acomete adultos
jovens, cuja manifestação mais comum é a proteinúria. Pode apresentar-se de forma
esporádica ou familiar, sendo necessários mais estudos para determinar o
envolvimento genético em sua patogênese.
INTRODUCTION: The knowledge evolution about the complement system resulted in new classifications of preexisting glomerulopathies and identification of new entities. C1q nephropathy (C1qN) is a rare disease, found in 0.21 to 2% of renal biopsies. It has a variable anatomopathological manifestation: from podocytopathies to proliferative forms. It has questionable response to immunosuppression, with a common pattern of corticosteroid resistance. The disease was described in 1985, however little is known about its pathophysiology and natural history. Cases of familial presentation of the disease lead us to question a possible genetic etiology. OBJECTIVES: the primary objectives were: to describe the clinical, laboratory and histopathological characteristics of cases of C1qN followed up in the Section of Glomerular Diseases of UNIFESP; and describe possible genetic mutations associated with the disease. METHODS: single-center retrospective observational study involving clinical and laboratory evaluation of all index cases and exome sequencing of part of patients with anatomopathological diagnosis of C1qN. RESULTS: five patients were diagnosed with NC1q, with ages of presentation between 15-45 years. The follow-up period ranged from 3 to 16 years. Most were female and presented focal segmental glomerulosclerosis in the kidney biopsy. Only one case had an anatomopathological pattern of minimal change disease, which had a better response to immunosuppression and maintained renal function. The others showed significant loss of glomerular filtration rate. Out of the five patients, three had a family history of chronic kidney disease of undetermined cause. One of the three patients who underwent exome evaluation had a mutation in the TP53RK gene, which encodes the TP53 kinase regulatory protein. DISCUSSION: C1q is an initial component of the classical complement pathway and plays a key role in immunity. The mechanism of glomerular deposition and injury in C1qN are unclear, and glomerular structural alterations, infections and complement dysregulation have been considered. The TP53RK gene is involved in the control of gene transcription. Its mutations were associated with neurorenal syndrome characterized by corticoresistant nephrotic syndrome and reduced podocyte survival, with no previous report of association with C1qN. CONCLUSION: C1qN is a rare disease that affects young adults, with the most common manifestation being proteinuria. It can be sporadic or familial, requiring further studies to determine the genetic involvement in its pathogenesis.
INTRODUCTION: The knowledge evolution about the complement system resulted in new classifications of preexisting glomerulopathies and identification of new entities. C1q nephropathy (C1qN) is a rare disease, found in 0.21 to 2% of renal biopsies. It has a variable anatomopathological manifestation: from podocytopathies to proliferative forms. It has questionable response to immunosuppression, with a common pattern of corticosteroid resistance. The disease was described in 1985, however little is known about its pathophysiology and natural history. Cases of familial presentation of the disease lead us to question a possible genetic etiology. OBJECTIVES: the primary objectives were: to describe the clinical, laboratory and histopathological characteristics of cases of C1qN followed up in the Section of Glomerular Diseases of UNIFESP; and describe possible genetic mutations associated with the disease. METHODS: single-center retrospective observational study involving clinical and laboratory evaluation of all index cases and exome sequencing of part of patients with anatomopathological diagnosis of C1qN. RESULTS: five patients were diagnosed with NC1q, with ages of presentation between 15-45 years. The follow-up period ranged from 3 to 16 years. Most were female and presented focal segmental glomerulosclerosis in the kidney biopsy. Only one case had an anatomopathological pattern of minimal change disease, which had a better response to immunosuppression and maintained renal function. The others showed significant loss of glomerular filtration rate. Out of the five patients, three had a family history of chronic kidney disease of undetermined cause. One of the three patients who underwent exome evaluation had a mutation in the TP53RK gene, which encodes the TP53 kinase regulatory protein. DISCUSSION: C1q is an initial component of the classical complement pathway and plays a key role in immunity. The mechanism of glomerular deposition and injury in C1qN are unclear, and glomerular structural alterations, infections and complement dysregulation have been considered. The TP53RK gene is involved in the control of gene transcription. Its mutations were associated with neurorenal syndrome characterized by corticoresistant nephrotic syndrome and reduced podocyte survival, with no previous report of association with C1qN. CONCLUSION: C1qN is a rare disease that affects young adults, with the most common manifestation being proteinuria. It can be sporadic or familial, requiring further studies to determine the genetic involvement in its pathogenesis.