The diagnosis of IH is histological and requires the demonstration of the following histological characteristics in three to five full-thickness biopsies of the intestinal wall: very low or absent activity of acetylcholinesterase activity in the mucosa; significant reduction of nerve cells in the myenteric and submucous plexus; and hypertrophy of the muscularis mucosa and muscle layers [7,8]. The gene discussed is ACHE; the disease is isolated hemihyperplasia.