Failure to thrive in a newborn: what's the cause?

Examination reveals jaundice and a large umbilical hernia

A 26-day-old term male infant is brought to the emergency department by his mother over concerns of lethargy and difficulty nursing. 

She reports that he needs to be awakened to nurse, and feeds for just a few minutes at a time.

Examination reveals jaundice, a large umbilical hernia, and an increase of just 85g from his birth weight.