In some diseases, such as osteogenesis imperfecta, new mutations are often present as asymptomatic somatic and germline mosaicism in one of the parents of the propositus.
What type of mutation causes osteogenesis imperfecta?
Mutations in several genes can lead to OI. About 80%–90% of OI cases are caused by autosomal dominant mutations in the type 1 collagen genes, COL1A1 and COL1A2. Mutations in one or the other of these genes cause the body to make either abnormally formed collagen or too little collagen.
What is an example of genetic mosaicism?
Examples of mosaicism include: Mosaic Down syndrome. Mosaic Klinefelter syndrome. Mosaic Turner syndrome.
What is the difference between somatic and germline mosaicism?
Germline mosaicism, also called gonadal mosaicism, is a type of genetic mosaicism where more than one set of genetic information is found specifically within the gamete cells; conversely, somatic mosaicism is a type of genetic mosaicism found in somatic cells.
How do you identify germline mosaicism?
How is germline mosaicism found? Women with germline mosaicism will not be found to be carriers via genetic carrier testing, because carrier testing is done on blood or saliva cells. Women with germline mosaicism have mutations in their egg cells, which will not show up on the blood or saliva test.
Is osteogenesis imperfecta a dominant or recessive trait?
When caused by mutations in the COL1A1 or COL1A2 gene, osteogenesis imperfecta has an autosomal dominant pattern of inheritance, which means one copy of the altered gene in each cell is sufficient to cause the condition.
What is the pathophysiology of osteogenesis imperfecta?
The most common form of OI is caused by mutations in the two collagen type I genes. Stop mutations usually lead to reduced collagen amount resulting in a mild phenotype, while missense mutations mainly provoke structural alterations in the collagen protein and entail a more severe phenotype.
What is fetal mosaicism?
Mosaicism refers to the presence in an individual (or a tissue) of two or more cell lines that differ in genotype or chromosomal constitution but have been derived from a single zygote. Mosaicism is the result of a mitotic mutation that occurs during embryonic, fetal or extrauterine development.
What is Somatic mosaicism?
Somatic mosaicism is the accumulation of mutations in DNA sequence or copy number in cellular genomes after fertilization. Somatic mutations are present in both normal cells and in various diseases. Somatic variations have been suggested to play a major role in driving neuronal diversity and genome evolution.
What is maternal mosaicism?
Maternal mosaicism When the mother has a population of cells in her body with one X chromosome instead of the usual two. Confined placental mosaicism (CPM) When there is a population of cells in the placenta with one X chromosome. These cells are only in the placenta and are not present in the baby.
What is the difference between somatic and germline?
Somatic mutations – occur in a single body cell and cannot be inherited (only tissues derived from mutated cell are affected) Germline mutations – occur in gametes and can be passed onto offspring (every cell in the entire organism will be affected)
Are germline cells somatic?
“Somatic cells” is a fairly general term which refers to essentially all the cells of the body except for the germ line; the germ line being the cells in the sexual organs that produce sperm and eggs. So anything that doesn’t have the job of producing sperm or eggs is a somatic cell.
Are germline cells pluripotent?
Numerous reports have shown that pluripotent cells can be generated and derived from germline stem cells (GSCs) in mouse and human testes during in vitro cultivation.
Is de novo a Mosaicist?
common cause of such genetic mosaicism is de novo mutations. and may include all or only some of the germ cells. (A totally different mechanism for somatic mosaicism has been recently described, reversion of a transmitted mutation to normal .
What are germline cells?
= A germ line is the sex cells (eggs and sperm) that are used by sexually reproducing organisms to pass on genes from generation to generation. Egg and sperm cells are called germ cells, in contrast to the other cells of the body that are called somatic cells.
What is non penetrance?
(non-PEH-neh-trunts) An instance in which an individual has a trait-associated or disease-causing genetic variant, but the individual does not have the phenotype or condition. An example of nonpenetrance is a woman with a BRCA1 pathogenic variant who lives to be elderly and never develops breast or ovarian cancer.