What is the most likely investigation?

A 2-year-old baby with atrophy of the buttocks, distended abdomen with frequent offensive smelly stool.

What is the most likely investigation?
A . Upper GI endoscopy
B . Colonoscopy
C . Stool culture
D . Sweat test
E . Endomysium/alpha gliadin antibody

Answer: E

Explanation:

Endomysium/alphagliadin antibody. Atrophy of buttock due to fat malabsorption and distended abdo (sometimes with everted umbilicus) with frequent offensive smelly stools are seen in coeliac disease. Hence gliadin antibody should be done.