Definition

Noun: A condition characterized by the failure of a tissue or organ to develop normally or completely, resulting in its absence or severe underdevelopment.

Usage

This is a medical term used specifically in pathology and developmental biology to describe a congenital or acquired developmental failure.

Examples

• The diagnosis confirmed aplasia of the thymus gland.
• Bone marrow aplasia is a serious condition requiring immediate treatment.
• The study focused on the genetic causes of renal aplasia.

Advanced Usage

• Pure red cell aplasia: A specific type of bone marrow failure where only the production of red blood cells is severely reduced or absent.
• Aplastic anemia: A broader clinical condition often involving bone marrow aplasia, leading to pancytopenia (a deficiency of all types of blood cells).

Variants and Related Words

• Aplastic (adjective): Pertaining to or characterized by aplasia.
  • The patient was diagnosed with aplastic anemia.
• Hypoplasia (noun): A related but distinct condition involving underdevelopment or incomplete development of a tissue or organ, but not a complete failure to form.

Synonyms

• Agenesis (particularly when referring to the complete absence of an organ due to a failure in embryonic development)
• Developmental failure

Notes on Meaning

While aplasia strictly refers to a failure to develop, in clinical contexts it is often used interchangeably with terms describing severe underdevelopment or absence. It is distinct from atrophy, which is the wasting away of a normally developed tissue or organ.

Noun

1. failure of some tissue or organ to develop