What Causes Williams Syndrome?
There are 20,000-25,000 genes in the human genome and Williams syndrome is caused by a deletion of about 25 of them from a specific region on chromosome 7. It is likely that the absence of a few of these genes (not all) causes the problems associated with Williams syndrome. Amongst the genes that are usually missing from affected individuals are CLIP2, ELN, and GTF21.
CLIP2 - codes for a protein called CAP-GLY domain containing linker protein 2; it is believed to play a role in the structure and function of nerve cells.
ELN - codes for a protein called elastin which is a major component of elastin fibres that provide strength and flexibility to connective tissue. Researchers have discovered that absence of ELN is associated with connective tissue problems and cardiovascular abnormalities.
GTF1 - codes for two proteins called BAP-135 and TFII-I. BAP-135 has a role in the immune system and contributes to the activation of B cells in response to foreign invaders. TFII-I is a transcription factor that is active in the brain and other parts of the body. Some scientists think that it is involved in the regulation of calcium into cells. It has also been postulated that loss of the GTF1 gene is associated with the learning disabilities observed in Williams syndrome.
At the time of writing (December 2009) the relationship between many of the deleted genes and Williams syndrome symptoms is unknown.
CLIP2 - codes for a protein called CAP-GLY domain containing linker protein 2; it is believed to play a role in the structure and function of nerve cells.
ELN - codes for a protein called elastin which is a major component of elastin fibres that provide strength and flexibility to connective tissue. Researchers have discovered that absence of ELN is associated with connective tissue problems and cardiovascular abnormalities.
GTF1 - codes for two proteins called BAP-135 and TFII-I. BAP-135 has a role in the immune system and contributes to the activation of B cells in response to foreign invaders. TFII-I is a transcription factor that is active in the brain and other parts of the body. Some scientists think that it is involved in the regulation of calcium into cells. It has also been postulated that loss of the GTF1 gene is associated with the learning disabilities observed in Williams syndrome.
At the time of writing (December 2009) the relationship between many of the deleted genes and Williams syndrome symptoms is unknown.
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