Title: Genetic Diseases - Biology Encyclopedia - cells, body, function, human, different, chromosomes, DNA, organs, blood
Headings: Genetic Diseases
Genetic Diseases
How Gene Defects Cause Disease
Inheritance Patterns in Genetic Disease
Unique Features of Genetic Diseases
Bibliography
User Contributions:
Donna

Content: Girls developmental retardation,  mutism, and movement disorder
Leber's Hereditary Optic Neuropathy
mitochondria, maternal inheritance
respiratory complex proteins
Degeneration of the central portion of the optic nerve, loss of  central vision
Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke (MELAS)
mitochondria, maternal inheritance
transfer RNA
Recurring, stroke-like episodes in which sudden headaches are  followed by vomiting and seizures; muscle weakness
Inheritance Patterns in Genetic Disease
Genetic diseases are heritable, meaning they may be passed from parent to  child. A disease gene is called recessive if both copies of the gene must be defective to cause the disease. Loss-of-function mutations are often recessive. If the second copy of the  gene is healthy, it may be able to serve adequately even if the first copy  suffers a loss-of-function mutation. In this case, the carrier of the  disease gene will not have the disease. All humans are thought to carry a number of such defective genes. Close  relatives are likely to carry similar genes and gene defects, and are  therefore more likely to bear children with recessive genetic diseases if  they mate. Because of this, a prohibition against marriage of close  relatives is found in virtually every culture in the world. A disease gene is called dominant if inheriting one copy of it causes the disease.