Rare cases of autoimmune hypothyroidism in young children.

Acquired autoimmune hypothyroidism is common in late childhood and adolescence but is very rare in the first 3 years of life. We report on three cases of autoimmune thyroiditis (AT) in young children who presented with constipation, decreased appetite, and increased hours of sleep. Our cases highlight that AT may remain undiagnosed for a long time in young children owing to the rarity of the disease.