Question

2 factors that affect the type and severity of abnormalities in an individual who is an aneuploid mosaic

Answer 1

Normal number of chromosomes present in a human cell is 46 or 23 pairs.When the number of chromosomes is 45 or 46 insted of usual 46, it is called as aneuploidy.Mosaic Down syndrome, or mosaicism, is a rare form of Down syndrome. Down syndrome is a genetic disorder that results in an extra copy of chromosome 21. People with mosaic Down syndrome have a mixture of cells. Some have two copies of chromosome 21, and some have 3 copies. Trisomy is the most common aneuploidy. In trisomy, there is an extra chromosome. A common trisomy is trisomy 21 (Down syndrome). Other trisomies include trisomy 13 (Patau syndrome) and trisomy 18 (Edwards syndrome).

The extra chromosome or missing chromosome may cause genetic disorders.Some cancer cells also have abnormal numbers of chromosomes. About 68% of human solid tumors are aneuploid.

Aneuploidy originates during cell division when the chromosomes do not separate properly between the two cells (nondisjunction). Most cases of aneuploidy in the germline result in miscarriage, and the most common extra autosomal chromosomes among live births are 21, 18 and 13.Chromosome abnormalities are detected in 1 of 160 live human births.

Aneuploidy occurs from errors in chromosome segregation, which can go wrong in several ways.

Aneuploidogens are the Agents capable of causing aneuploidy are called aneuploidogens. Many mutagenic carcinogens are aneuploidogens. X-rays, for example, may cause aneuploidy by fragmenting the chromosome; it may also target the spindle apparatus.[20] Other chemicals such as colchicine can also produce aneuploidy by affecting microtubule polymerization.

Exposure of males to lifestyle to these Aneuploidogens , environmental and/or occupational hazards may increase the risk of spermatozoa aneuploidy. Tobacco smoke contains chemicals that cause DNA damage. Smoking also can induce aneuploidy. For instance, smoking increases chromosome 13 disomy in spermatozoa by 3-fold, and YY disomy by 2-fold.Occupational exposure to benzene is associated with a 2.8-fold increase of XX disomy and a 2.6-fold increase of YY disomy in spermatozoa.Pesticides are released to the environment in large quantities so that most individuals have some degree of exposure.

Symtoms of aneuploid mosaic are severe microcephaly , growth deficiency and short stature , mild physical abnormalities, eye abnormalities, problems with the brain and central nervous system , seizures , developmental delay , and intellectual disability.

Errors in chromosome segregation lead to aneuploidy, a state where the number of chromosomes in a cell or organism deviates from multiples of the haploid genome. Aneuploidy arising through chromosome mis-segregation during meiosis is a major cause of infertility and inherited birth defects.