[Incomplete hemolytic uremic syndrome associated with partial factor H deficiency]. / Síndrome hemolítico urémico incompleto asociado a déficit parcial de factor H.

Hemolytic uremic syndrome (HUS) consists of the association of hemolytic anemia, thrombocytopenia and renal failure. Most cases are related to toxins (verotoxins) produced by Escherichia coli 0157:H7 and generally have good renal prognosis. Atypical forms can occur, with a less favorable prognosis, and can be due to mutations in the gene codifying factor H, a protein that regulates activation of the alternative complement pathway, among other causes. Factor H deficiency produces continuous complement activation, causing injury to capillary endothelial cells. We report a case of incomplete (absence of thrombocytopenia and uremia), atypical HUS in which hypocomplementemia secondary to partial factor H deficiency was detected, with favorable outcome. Prior to symptom onset, the patient had a Campylobacter infection, precipitating the symptoms. Genetic analysis showed a heterozygous mutation (C846T) located in the SCR4 domain, generating an amino acid change in the factor H molecule (Pro240Leu). This mutation may have been the cause of the partial factor H deficiency and the patient's symptoms on admission.

Síndrome hemolítico urémico incompleto asociado a déficit parcial de factor H / Incomplete hemolytic uremic syndrome associated with partial factor H deficiency

El síndrome hemolítico urémico (SHU) asocia anemia hemolítica, trombocitopenia e insuficiencia renal. La mayoría de los casos están relacionados con las toxinas (verotoxinas) producidas por Escherichia coli 0157:H7 y generalmente tienen un buen pronóstico renal. Existen formas atípicas, con peor pronóstico, que pueden ser secundarias, entre otras causas, a mutaciones en el gen codificador del factor H, proteína que regula la activación de la vía alternativa del complemento. Su déficit, produce una activación continua del complemento, dañando las células endoteliales de los capilares. Presentamos un caso clínico de SHU incompleto (ausencia de plaquetopenia y uremia) y atípico en el que se detectó una hipocomplementemia secundaria a un déficit parcial de factor H, cuya evolución fue favorable. Previo al inicio de los síntomas, el paciente presentó una infección por Campylobacter que actuó como agente precipitante del cuadro. El análisis genético demostró una mutación en heterocigosis (C846T) localizada en el dominio SCR4 que genera un cambio de aminoácido en la molécula del factor H (Pro240Leu). Es posible que dicha mutación haya sido la causante del déficit parcial del factor H y del cuadro que presentó al ingreso

Hemolytic uremic syndrome (HUS) consists of the association of hemolytic anemia, thrombocytopenia and renal failure. Most cases are related to toxins (verotoxins) produced by Escherichia coli 0157:H7 and generally have good renal prognosis. Atypical forms can occur, with a less favorable prognosis, and can be due to mutations in the gene codifying factor H, a protein that regulates activation of the alternative complement pathway, among other causes. Factor H deficiency produces continuous complement activation, causing injury to capillary endothelial cells. We report a case of incomplete (absence of thrombocytopenia and uremia), atypical HUS in which hypocomplementemia secondary to partial factor H deficiency was detected, with favorable outcome. Prior to symptom onset, the patient had a Campylobacter infection, precipitating the symptoms. Genetic analysis showed a heterozygous mutation (C846T) located in the SCR4 domain, generating an amino acid change in the factor H molecule (Pro240Leu). This mutation may have been the cause of the partial factor H deficiency and the patient's symptoms on admission