医学遗传学课件-线粒体疾病的遗传.pptVIP

Medical Genetics Medical Genetics 线粒体疾病的遗传 Inheritance of Mitochondrail Diseases The normal 46 chromosomes in our body are contained in the center of the cell, which is called the nucleus. Mitochondria are structures in the cell located outside of the nucleus in the cytoplasm, that also contain genes that are separate from the ones in the nucleus. Mitochondria are extremely small (from .002-.008 millimeters in length) rice-shaped structures whose details can only be seen with the electron microscope . Mitochondria are often called the “powerhouses” of the cell because they are the site where sugar is broken down to release the energy required for cellular functions. A cell may have hundreds or even thousands of mitochondria depending on the particular cell’s need for energy. (For example, the average human liver cell contains more than a thousand mitochondria.)? In addition to containing the many proteins needed to control the energy release process, the mitochondria also contain a small amount of DNA that is used to direct the manufacture of thirteen of the proteins needed for its activities. Unlike nuclear genes, which are inherited from both parents, mitochondrial genes are inherited only from the mother. If there is a mutation in a mitochondrial gene, it is passed from a mother to all of her children; sons will not pass it on, but daughters will pass it on to all of their children, and so on. The first human disease that was associated with a mutation in mitochondrial DNA is called Lebers Hereditary Optic Neuropathy, or LHON.  ?????????????????????????????????????Intense SDH stainingof a muscle fiber withmitochondrial proliferation mtDNA Point mutationsCardiomyopathyLebers optic neuropathyLeighs syndromeMELASMERRFNARP/MILSSingle deletion or duplicationAtaxia, LeukodystrophyDiabetes: Maternal inheritance ? Kearns-SayrePearsonsPEO: Sporadic Multiple deletionsAgin