Mutation, point
A single nucleotide base change in the DNA. A point mutation may consist of the loss of a nucleotide, the insertion of an additional nucleotide, or the substitution of one nucleotide for another.
The first point mutation discovered in humans involved the substitution of one nucleotide for another. It was in sickle hemoglobin, the molecular basis for sickle cell trait and sickle cell anemia. The mutation results in an amino acid change from glutamic acid to valine, from normal adult hemoglobin (hemoglobin A) to sickle hemoglobin (hemoglobin S).
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A rare mutation found usually only in a single family or a small population. (It is like a privately printed book.)
- Mute
A mute is a person who does not speak, either from an inability to speak or an unwillingness to speak. The term “mute” is specifically applied to a person who, due to profound congenital (or early) deafness, is unable to use articulate language and so is deaf-mute. A mute in speech is a letter that […]
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The inability or unwillingness to speak. A person who is mute cannot or does not care to talk. Someone who was mute was said to be dumb, not in the sense of being stupid, but in the sense of being devoid of the power of speech. The term “mutism” is specifically applied to people who, […]
- Mutism, akinetic
A state in which a person is unable to speak (mute) or move (akinetic). Akinetic mutism is often due to damage to the frontal lobes of the brain.
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Complete lack of speech (mutism) that is believed to be volitional (willed) on the part of the patient. True elective mutism may be a reaction to a traumatic event, the aftermath of an injury to the mouth or throat, particularly if it is painful, or a symptom of extreme shyness. In some cases, the lack […]