Cretinism, a condition characterised by stunted growth and mental retardation in children, is caused by a disorder of which endocrine gland when it is underactive in early life?

Introduction / Context:
Endocrine glands produce hormones that are essential for normal growth and development. When these glands do not function properly, characteristic disorders can occur. Cretinism is a term used for severe hypothyroidism present from birth or early childhood, leading to physical and mental developmental problems. Exam questions often ask which gland is involved in cretinism to test understanding of thyroid hormone functions.

Given Data / Assumptions:

• The disorder mentioned is cretinism in children.
• It is associated with stunted growth and mental retardation.
• The options include thymus, parathyroid, thyroid, and adrenal glands.
• We assume standard textbook descriptions of endocrine disorders.

Concept / Approach:
The thyroid gland, located in the neck, secretes thyroid hormones such as thyroxine, which regulate metabolism and are crucial for normal growth and brain development in children. If the thyroid gland is underactive from birth or early childhood, causing severe deficiency of thyroid hormones, the result can be cretinism. Children with untreated cretinism show delayed physical growth, coarse facial features, and intellectual disability. Disorders of the thymus, parathyroid, or adrenal glands cause different problems, not classical cretinism.

Step-by-Step Solution:
Step 1: Identify cretinism as a condition linked to congenital or early hypothyroidism. Step 2: Recall that the thyroid gland produces hormones that influence growth, brain development, and metabolic rate. Step 3: Understand that lack of thyroid hormone during critical stages of development can lead to irreversible physical and mental developmental delays. Step 4: Thymus gland is involved in immune system development, parathyroid glands regulate calcium, and adrenal glands produce cortisol and other hormones, none of which cause classical cretinism when underactive. Step 5: Therefore, the endocrine gland whose disorder leads to cretinism is the thyroid gland.

Verification / Alternative check:
Medical and biology texts describe two main thyroid hormone deficiency conditions: cretinism in children and myxoedema in adults. Cretinism is consistently associated with hypothyroidism in early life, before the brain and skeleton have fully developed. These books emphasise the importance of iodine, which the thyroid gland needs to make thyroid hormones, and note that iodine deficiency can cause goitre and cretinism. No such association is made for thymus, parathyroid, or adrenal glands, confirming that the thyroid is responsible.

Why Other Options Are Wrong:
Thymus gland mainly supports the immune system by helping in the maturation of T lymphocytes. Its disorders affect immunity rather than producing cretinism, so option A is incorrect. Parathyroid gland controls calcium and phosphate balance; its dysfunction causes problems like tetany or bone disease, not cretinism, so option B is wrong. Adrenal gland disorders affect stress response, salt balance, and metabolism, leading to conditions like Addison disease or Cushing syndrome, but not cretinism, making option D incorrect.

Common Pitfalls:
Some students confuse different glands because many endocrine disorders affect growth or metabolism. They may also mix up thyroid and parathyroid glands due to their similar names and close anatomical location. To avoid this, remember that thyroid hormones are directly linked to growth and brain development in children, while parathyroid hormones regulate calcium levels. Linking cretinism with childhood hypothyroidism and hypothyroidism with the thyroid gland will help you choose the correct answer.

Final Answer:
The correct choice is Thyroid gland, because cretinism results from severe deficiency of thyroid hormones due to an underactive thyroid gland in early life.