A 7-year-old adopted patient weighs 20 kg and presents with a swollen, non-painful geographic tongue. What is the most likely underlying cause?

Correct answer: B. Malnutrition / nutritional deficiency

• A. Type 1 diabetes causes polyuria, polydipsia and weight loss but does not characteristically produce geographic tongue.
• B. Correct. 20 kg is well below the ~23 kg 50th percentile for age. Low weight plus glossitis-type tongue change points to nutritional deficiency (B-complex, iron, zinc) — common in children with disrupted early feeding histories.
• C. Iron overload (hemochromatosis) causes skin bronzing and organ damage, not swollen geographic tongue in a child.
• D. Mouth breathing causes anterior gingival dryness and gingivitis, not a swollen depapillated tongue.