A Diagnostic Quagmire: PFIC5 Presenting as a Rare Cause of Neonatal Cholestasis.

Progressive familial intrahepatic cholestasis is a heterogeneous group of autosomal recessive disorders defined by defects in bile excretion and transport. We describe a 6-week-old boy from Micronesia presenting with failure to thrive and jaundice. His diagnostic workup was remarkable for direct hyperbilirubinemia, hepatitis, and hepatic ultrasound with possible portosystemic shunting. The presence of toxoplasma IgG initially raised concern for congenital toxoplasmosis. Ultimately, the absence of bile salt export pump staining on liver histology and subsequent genetic studies confirmed a diagnosis of progressive familial intrahepatic cholestasis type 5, an exceedingly rare cause of neonatal cholestasis.