Hypoplasia

From Wikipedia, the free encyclopedia

Hypoplasia is underdevelopment or incomplete development of a tissue or organ.^[1] Although the term is not always used precisely, it properly refers to an inadequate or below-normal number of cells.^[2] Hypoplasia is similar to aplasia, but less severe. It is the opposite of hyperplasia (too many cells).

The name is derived from the Greek: hypo, meaning low, and plasis, which refers to molding or forming.^[3] The adjective form is hypoplastic.

Hypoplasia can be present in any tissue or organ. It is descriptive of many medical conditions such as:

Underdeveloped:

• breasts during puberty.
• testes in Klinefelter's syndrome.
• ovaries in Fanconi anemia, gonadal dysgenesis, trisomy X
• thymus in DiGeorge syndrome.
• labia majora in popliteal pterygium syndrome.
• cerebellum caused by mutation in the Reelin gene.
• tooth caused by oral pathology, such as Turner's hypoplasia.
• chambers of the of the heart in hypoplastic left heart syndrome and hypoplastic right heart syndrome
• optic nerve in optic nerve hypoplasia
• sacrum in sacral agenesis
• facial muscle in asymmetric crying facies
• thumb from birth.
• lungs, often as a result of oligohydramnios during gestation or the existence of congenital diaphragmatic hernia.

[edit] References

1. ^ Definition: hypoplasia from Online Medical Dictionary
2. ^ http://activate.lww.com/semdweb/internetsomd/ASP/1527483.asp
3. ^ http://activate.lww.com/semdweb/internetsomd/ASP/1527483.asp

[edit] See also

• Aplasia, when an organ (or part of an organ) is entirely missing
• Atrophy, when an existing part wastes away
• Dysplasia, abnormal development of an organ or extremity
• Neoplasia, new, disordered growth of tissue