An 8 week baby boy is noted to be jaundiced. He is breast-feeding well and has gained 300 g since birth. His stools are yellow and his urine is pale straw colored. What is the most likely diagnosis?

The key is A. Galactosemia. [Galactosemia is a family of genetic disorders that result from compromised ability to metabolize the sugar galactose; the term “galactosemia” literally means too much galactose in the blood. Biliary atresia causes obstructive picture where stools are pale and urine becomes dark. Hemolytic disorder like G6PD or spherocytosis causes appearance of jaundice in 1st 24 hours. In breastmilk jaundice, jaundice develops in 2nd week. Also congenital viral infection (TORCH) occurs in 1st 24 hours. Here there is failure to thrive also. So likely cause in the presented case is Galactosemia].