Delayed diagnosis of 3β‐HSD7 deficiency in adolescence: Two case reports and review of the literature

ABSTRACT Congenital bile acid synthesis defects (BASD), the most common of which is 3β‐hydroxy‐Δ5‐C27‐steroid dehydrogenase oxidoreductase (3β‐HSD7) deficiency, are a rare cause of fat‐soluble vitamin malabsorption. We describe a 14‐year‐old girl who presented at 14 months with a left distal femur fracture and failure to thrive. It was not until 13 years of age that after several hospitalizations for bleeding and severe vitamin K deficiency, the patient was ultimately diagnosed with 3β‐HSD7 deficiency. We also describe the case of an adolescent girl who was referred for treatment of Hepatitis C (HCV) and diagnosed with 3β‐HSD7 deficiency after she failed to respond to therapy as expected. Finally, we review the diagnosis of BASD and highlight the challenges involved in our clinical cases. These cases demonstrate the importance of maintaining a broad differential when evaluating any patient with unexplained fat‐soluble vitamin deficiencies and represent unique presentations of 3β‐HSD7 deficiency in adolescent patients.