Chromosome 8
Translocations of genetic material between chromosome 8 and other chromosomes can cause Myeloproliferative syndrome 8p11. This condition is characterized by a greater number of white blood cells (myeloproliferative disorder) and the development of lymphoma, a blood-related cancer that causes the formation of tumors in the lymph nodes. Myeloproliferative disorder usually develops into another form of blood cancer called acute myeloid leukemia. The most common translocation involved in this condition, written as t (8; 13) (p11; q12), fuses part of the FGFR1 gene on chromosome 8 with part of the ZMYM2 gene on chromosome 13. Translocations are found only in cells cancerous
The protein produced by the normal FGFR1 gene can "activate" cellular signaling that helps the cell respond to its environment, for example, by stimulating cell growth. The protein produced from the fused gene, regardless of the associated gene involved, leads to a constant signaling of FGFR1. Uncontrolled signaling promotes growth and continuous cell division, which leads to cancer.
A type of blood cancer known as Acute myeloid leukemia is associated with a rearrangement (translocation) of genetic material between chromosomes 8 and 21. This rearrangement is associated with approximately 7 percent of cases of acute myeloid leukemia in adults. The translocation, written as t (8; 21), fuses part of the RUNX1T1 gene (also known as ETO) of chromosome 8 with part of the RUNX1 gene of chromosome 21. This mutation is acquired during a person's life and occurs only in some cells of the organism, therefore it is not a condition that can be inherited.
A rearrangement of chromosome 8 causes Recombinant 8 syndrome, a condition that involves abnormalities of the heart and urinary tract, moderate to severe intellectual disability and a distinctive facial appearance. This reorganization results in a removal of a part of the short arm (p) and a duplication of a part of the long arm (q). The signs and symptoms of recombinant syndrome 8 are related to the loss of genetic material in the short arm of chromosome 8 and the presence of additional genetic material in the long arm of chromosome 8; investigations continue to specify the genes involved.
Type II trichorhinophalangeal syndrome (TRPS II) is caused by a removal of genetic material in the long arm (q) of chromosome 8. TRPS II is a condition that causes bone and joint malformations; distinctive facial features; intellectual disability; and abnormalities of the skin, hair, teeth, sweat glands and nails. The signs and symptoms of TRPS II are related to the loss of multiple genes from this part of the chromosome. The size of the elimination varies among affected individuals.
The TRPS1, EXT1 and RAD21 genes are missing in people with TRPS II. Researchers have determined that the loss of the EXT1 gene is responsible for multiple benign (non-cancerous) bone tumors called osteochondromas seen in people with TRPS II. It is believed that loss of the TRPS1 gene causes other bone and facial abnormalities. The elimination of the RAD21 gene can contribute to intellectual disability. The loss of other genes in this region of chromosome 8 probably contributes to the additional characteristics of this condition.
Other types of cancer Translocations between chromosome 8 and other chromosomes have been associated with other types of cancer. For example, Burkitt lymphoma (a cancer of white blood cells called B cells that occurs most often in children and young adults) can be caused by a translocation between chromosomes 8 and 14. This translocation, written t (8; 14) (q24; q32), leads to continuous cell division without control or order, which probably contributes to the development of Burkitt lymphoma. Less frequently, Burkitt lymphoma can be caused by translocations between chromosomes 8 and 2 or chromosomes 8 and 22.
Trisomy 8 is incompatible with life, so an embryo with this condition will not reach term. However, a mosaic trisomy 8 can occur, in which only some body cells have this condition. The disorders associated with trisomy 8 are multiple; Mental retardation, distinctive facial features, liver or other organ problems, leukemia, lack of the corpus callosum (brain tissue), among others.
