25th May 2025

A 5-day-old baby was born without significant medical issues, and his mother reports that her pregnancy was unremarkable.

A 5-day-old baby was born without significant medical issues, and his mother reports that her pregnancy was unremarkable. Her baby has been exclusively breast-fed since birth. He began to develop poor feeding and appeared generally lethargic since then, with episodes of vomiting. He was well prior to this. Examination reveals an enlarged liver and jaundice with moderate hypotonia. Blood tests reveal mixed hyperbilirubinemia, transaminitis, and a mildly elevated prothrombin time.

Which of the following is the likely underlying diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.