| optic atrophy | Atrophy of the optic disk resulting from degeneration of the nerve fibres of the optic nerve and optic tract. (12 Dec 1998) |
|---|---|
| optic atrophy, hereditary | An inherited disorder in which optic atrophy is associated with muscle weakness, peroneal muscular atrophy and, in some patients, lancinating pains. In these patients the peripheral sensory neurons are probably affected. (12 Dec 1998) |
| Leber's hereditary optic atrophy | Hereditary degeneration of the optic nerve and papillomacular bundle with resulting rapid loss of central vision, progressive for several weeks, then usually stationary with permanent central scotoma; age of onset is variable, most often in the third decade; more males than females are affected and transmission is cytoplasmic and strictly on the female side. Mutation on the mitochondrial chromosome involved, which presumably interacts with an X-linked mutant. This mechanism may explain the bizarre sex ratio, which differs significantly from one country to another. (05 Mar 2000) |
| autosomal dominant | <genetics> Requires only one affected parent have the trait to pass it to offspring. (02 Jan 1998) |
| genes, dominant | Genes that are reflected in the phenotype both in the homozygous and the heterozygous state. (12 Dec 1998) |
| permanent dominant idea | An exaggerated notion, belief, or delusion that persists, despite evidence to the contrary, and controls the mind, the obstinate conviction of a psychotic person regarding the correctness of his delusion. Synonym: idee fixe, overvalued idea, permanent dominant idea. (05 Mar 2000) |
| dominant | <genetics> A gene is said to be dominant if it expresses its phenotype even in the presence of a recessive gene. (09 Oct 1997) |
| dominant character | An inherited character determined by one kind of allele. See: phenotype. (05 Mar 2000) |
| dominant eye | The eye that is customarily used for monocular tasks. Synonym: master eye. (05 Mar 2000) |
| dominant frequency | The frequency occurring most often in an electroencephalogram. (05 Mar 2000) |
| dominant gene | dominance of traits |
| dominant hemisphere | That cerebral hemisphere containing the representation of speech and controlling the arm and leg used preferentially in skilled movements; usually the left hemisphere. (05 Mar 2000) |
| dominant idea | An idea that governs all one's actions and thoughts. (05 Mar 2000) |
| dominant inheritance | dominance of traits |
| dominant lethal trait | Trait, expressed in the phenotype if present in the genotype, that precludes having descendants. All such cases are necessarily sporadic and must represent new mutations as the usual methods of classical genetics provide no means of demonstrating any genetic component whatsoever, except for tenuous arguments such as advanced paternal age. Molecular biology may help although the methods may be tedious; if there is an epistatic gene that may mask the trait, the logic is more tractable, though complex. (05 Mar 2000) |