Dystrophy, cone
Dystrophy, cone: A disease of the cones, the specialized light-sensitive cells that act as photoreceptors in the retina of the eye, providing sharp central vision and color vision. The cone dystrophies are a form of genetic macular degeneration characterized by progressive deterioration of the cones that leads to the distinctive triad of loss of color vision, photophobia, and reduced central vision. Cone dystrophy genes have been mapped to chromosome regions 6p21.1, 6q25-q26, 17p12-13, and Xp21.1-p11.3. In region 6p21.1, mutations have been found in the gene that encodes GCAP1, a key component in the recovery of photoreceptor cells to the dark-adapted state after exposure to a light stimulus.
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Dystrophy, muscular: One of a group of genetic diseases characterized by progressive weakness and degeneration of the skeletal or voluntary muscles which control movement. The muscles of the heart and some other involuntary muscles are also affected in some forms of muscular dystrophy, and a few forms involve other organs as well. The major forms […]
- Dystrophy, myotonic
Dystrophy, myotonic: An inherited disease in which the muscles contract but have decreasing power to relax — this phenomenon is termed myotonia (irritability and prolonged contraction of muscles). The disease also produces leads to a mask-like expressionless face, premature balding, cataracts, and heart arrhythmias (abnormalities in heart rhythm). The onset of such problems is usually […]
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Our Symptoms article on Burning Urination provides a comprehensive look at the possible causes and treatments of Burning Urination. Dysuria: Pain during urination, or difficulty urinating. Dysuria is usually caused by inflammation of the urethra, frequently as a result of infection.
- Dwarfism, achondroplastic
Dwarfism, achondroplastic: A genetic disorder of bone growth, achondroplasia is the most common cause of short stature with disproportionately short limbs — dwarfism with short arms and legs. There is a typically large head with prominence of the forehead (frontal bossing), underdevelopment (hypoplasia) of the midface with cheekbones that lack prominence, and a low nasal […]
- Dwarfism
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