Microcephaly
An abnormally small head due to failure of brain growth. Microcephaly is an ominous sign because it is almost always associated with developmental delay and mental retardation. Many factors can impair the growth of the brain, including intrauterine infections (such as rubella, cytomegalovirus, and toxoplasmosis), intrauterine chemical exposure (such as in fetal alcohol syndrome), excessive radiation exposure (as in an atomic bomb explosion), chromosome abnormalities (such as trisomy 13 and trisomy 18), and genetic syndromes (such as Fanconi syndrome and Williams syndrome). The opposite of microcephaly is macrocephaly.
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- Microcystic corneal dystrophy
Cogan corneal dystrophy. It is also known, to add to the confusion, as map-dot-fingerprint type corneal dystrophy.
- Microcytic
Literally, referring to any abnormally small cell; in practice, referring to an abnormally small red blood cell. For example, microcytic anemia is characterized by small red blood cells. The opposite of microcytic is macrocytic.
- Microdeletion
Loss of a tiny piece’a piece that may be too small to be seen readily through a microscope’from a chromosome. Microdeletions can be detected via high-resolution chromosome banding, molecular chromosome analysis (with FISH), or DNA analysis. Disorders caused by microdeletions include Angelman, DiGeorge, Prader-Willi, and Williams syndromes.
- Microduplication
The gain of a tiny piece of a chromosome, a piece so small its presence is not apparent on ordinary examination (using a regular light microscope to look at chromosomes prepared in the usual fashion). The detection of microduplications requires special techniques such as high-resolution chromosome banding, molecular chromosome analysis (with FISH), or molecular genetic […]
- Microdosimetry
A technique for measuring the microscopic distribution of energy, useful with different types of radiation. Microdosimetry provides the scientific underpinnings for the measurement of radiation. It is vitally important to both radiation therapy and radiation protection. The prefix “micro-” is derived from the Greek “mikros” meaning small. It diminishes whatever it precedes.