Síndrome urémico hemolítico atípico de presentación neonatal / Atypical hemolytic uremic syndrome of neonatal presentation

El Síndrome urémico hemolítico (SUH) tiene formas típicas y atípicas. Se describe una variedad de formas genéticas con pobre pronóstico. Presentamos un bebé prematuro de 36 semanas, de bajo peso al nacer, quien a las 2 semanas de vida cursó con sepsis y necrosis intestinal siendo sometido a cirugía para realizarle ileostomía. Evolucionó con hipertensión arterial, hematuria, falla renal aguda y proteinuria persistente. A los 2 meses de vida, posterior al cierre de ileostomía, cursó con shock séptico y falleció. La biopsia renal post mortem mostró cuadro compatible de SUH. Dos años después, un hermano debutó a los 2 días de vida con síndrome nefrótico congénito. El estudio genético reveló que la madre era portadora del gen NPHS1 y el padre, del Factor I de complemento. El segundo hijo era portador de ambos genes.

Hemolytic Uremic Syndrome (HUS) has typical and atypical presentations. A variety of genetic forms, with poor prognosis are described. We report a 36 week premature baby, low birth weight, who at 2 weeks of life evolved with sepsis and intestinal necrosis undergoing surgery for ileostomy, hypertension, hematuria, acute renal failure and persistent proteinuria. At 2 months, after ileostomy closure, developed irreversible septic shock and died. Postmortem renal biopsy was compatible with HUS. Two years later, a brother presented after 2 days of birth with congenital nephrotic syndrome. Genetic studies revealed that the mother was carrying the gene NPHS1 and the father, factor I of complement. The second child was a carrier of both genes.

Severe deficiency of the specific von Willebrand factor-cleaving protease (ADAMTS 13) activity in a subgroup of children with atypical hemolytic uremic syndrome.

OBJECTIVE: The von Willebrand factor-cleaving protease (VWF-cp) activity has been reported to be deficient in adults with thrombotic thrombocytopenic purpura (TTP) and generally normal in adults with hemolytic uremic syndrome (HUS). The goal of this study was to determine VWF-cp activity in children with typical postdiarrheal (d+) HUS or atypical non-postdiarrheal (d-) HUS. Study design We measured VWF-cp activity in the plasma of 64 children with either (d+) HUS (n = 41) or (d-) HUS (n = 23). RESULTS: In the acute phase of HUS, VWF-cp activity was normal (>50%) in 54 children and undetectable (<5%) in one (d+) HUS and in 6 (d-) HUS children. After a 3-month remission, the (d+) HUS patient recovered a 100% VWF-cp activity, and the 6 (d-) HUS patients kept an undetectable level. In these 6 (d-) HUS patients, the disease was characterized by a neonatal onset and several relapses (hemolytic anemia, thrombocytopenia, transient acute renal failure, cerebral ischemia), and sometimes the development of arterial hypertension or end stage renal failure. CONCLUSION: A subgroup of pediatric patients with atypical (d-) HUS, with hematologic symptoms starting at birth and a recurrent course progressively involving kidney and brain, is related to VWF-cp deficiency and actually corresponds to Upshaw-Schulman syndrome revisited as congenital TTP.

[Neonatal hemolytic-uremic syndrome, methylmalonic aciduria and homocystinuria caused by intracellular vitamin B 12 deficiency. Value of etiological diagnosis]. / Syndrome hémolytique et urémique néonatal, acidurie méthylmalonique et homocystinurie par déficit intracellulaire de la vitamine B12. Intérêt du diagnostic étiologique.

BACKGROUND: A hemolytic-uremic syndrome associated with methylmalonic aciduria and homocystinuria is seen during the first weeks of life. A molecular defect in the CbIC mutation has been found. This report describes a new case with this association. CASE REPORT: A girl, the second in this family, was born at term: her birth weight was 2,100 g, height was 47 cm and head circumference 31.5 cm. She was admitted at 32 days of age with hemolytic anemia and fragmencytosis, renal failure and thrombocytopenia. The renal failure required peritoneal dialysis followed by hemofiltration. The signs of pancytopenia of central origin and liver failure seen at that time raised the possibility of an intracellular defect of B12 metabolism. Chromatography of the amino acids and organic acids in the urine and plasma revealed homocystinemia, hypomethioninemia, homocystinuria and methylmalonic aciduria. The deficient B12 metabolism was confirmed in fibroblasts which showed deficits in both methyl and adenosyl-cobalamin synthesis. The metabolic disturbances were completely resolved after intravenous administration of hydroxy-cobalamin (2,000 micrograms per day) and folinic acid (25 mg per day) for 5 days. But the neurological abnormalities persisted, with retinitis pigmentosa and major leukodystrophic changes seen by MRI, and the infant died one month later. CONCLUSION: This new case emphasizes the importance of systematically screening all cases of neonatal hemolytic-uremic syndrome for this autosomal recessive disorder.

Possible gonadal mosaicism in a family with hemoglobin Köln.

A brother and sister were the first members of a family to possess hemoglobin Köln (alpha 2 beta 2(98) Val leads to Met). Studies of these siblings and their parents strongly indicated that the anomaly had arisen by spontaneous mutation. Gonadal mosaicism of one of the parents offers the best explanation for the appearance of a spontaneous mutation in multiple members of a sibship.