Thyroid gland plays a key role in various body functions.

Hypothyroidism

The thyroid gland is in front of the neck below the voice box and is responsible for controlling the body functions. Hypothyroidism is a disease in which the thyroid gland does not produce enough specific hormones for controlling the body.

Causes:

Hashimoto's disease
Thyroiditis
Congenital hypothyroidism
Thyroid surgery
Medication
Pituitary gland abnormalities
Iodine imbalance

Diagnosis:

Doctor's examination
Blood tests: T4 or TSH
Ultrasound or MRI

Source:

medicalnewstoday