Colestasis por deficiencia de 3β-Δ5-C27-hidroxiesteroide deshidrogenasa en un paciente con alteración en la síntesis de ácidos biliares

Introduccion: Los errores innatos en la sintesis de acidos biliares son un grupo de defectos geneticos que representan del 1 al 2% de las enfermedades colestasicas cronicas en lactantes, ninos y adolescentes. La deficiencia de 3b-Δ5-C27-hidroxiesteroide oxidoreductasa (3b-HSDH) es el defecto mas comunmente reportado. El cuadro clinico caracteristico consiste en hepatitis neonatal, hepatomegalia, esplenomegalia, malabsorcion, desnutricion y enfermedad hepatica de aparicion tardia. Caso clinico: Lactante masculino con antecedente de ictericia en escleras a los 4 meses que se resolvio espontaneamente; posteriormente, a los 18 meses, presento enfermedad colestasica. Durante su abordaje se documento gamma-glutamil transpeptidasa normal, hallazgo que es altamente sugestivo de alteracion en la sintesis de acidos biliares. El diagnostico se realizo con espectrometria de masas en orina. Se inicio tratamiento con acido colico oral, y presento mejoria inmediata. Conclusiones: El resultado en los acidos biliares urinarios es definitivo para el defecto genetico y consistente con mutaciones homocigotas en el gen HSD3B7. Este padecimiento constituye un diagnostico de exclusion en las enfermedades colestasicas de la infancia, particularmente el hallazgo de gamma-glutamil transpeptidasa normal o levemente aumentada, y responde adecuadamente al tratamiento oral, por lo que debe identificarse de forma temprana. Background: Inborn errors in bile acid synthesis are a group of genetic defects accounting for 1 to 2% of chronic cholestatic diseases in infants, children and adolescents. Deficiency of 3b-Δ5-C27-hydroxysteroid dehydrogenase (3β-HSDH) is the most common defect in this disease. Clinical features consist of neonatal hepatitis, hepatomegaly, splenomegaly, malabsorption, malnutrition, and late-onset liver disease. Case report: A male infant who presented jaundice in sclera at 4 months that resolved spontaneously, later presented cholestatic disease at 18 months. During his approach, normal gamma-glutamyl transpeptidase was documented, a finding that is highly suggestive of alteration in the synthesis of bile acids. The diagnosis was made using urine mass spectrometry. Oral colic acid treatment was started, presenting immediate improvement. Conclusions: The result in urinary bile acids is definitive for the genetic defect and consistent with homozygous mutations in the HSD3B7 gene. This condition is a diagnosis of exclusion in childhood cholestatic diseases, particularly in the presence of normal or mildly enlarged gamma-glutamyl transpeptidase, and responds adequately to oral treatment; it should be identified early.