Hashimoto's thyroiditis, also known as chronic lymphocytic or autoimmune thyroiditis is a chronic autoimmune thyroid disease characterised by thyroid autoantibodies, with presence of thyroid peroxidase antibodies, lymphocyte infiltraton and thyroglobulin antibodies.1 It is present in around 20-30% of patients with thyroid diseases.2 It is the most common cause of hypothyroidism, more common in women of age 30 to 50 years.3 Hashimoto's thyroiditis presents with goitre, fatigue, weight gain, hair loss, bradycardia, constipation, abnormal menstruation, difficulty concentrating.4 The gene discussed is TG; the disease is hypothyroidism.