Gavin and Ming-Hui

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Nature of the Genetic Difficulty Bloomsyndrome-1.jpg

Bloom's Syndrome is caused by a mutation in a gene on Chromosome 15 which limits the activity of DNA helicase, an enzyme which is involved in DNA replication. As a result, DNA replication in patients with Bloom's Syndrome often produces mutations, increasing cancer risk and causing respiratory problems and skin rashes. The process of "crossing over" that occurs during DNA replication in homologous chromosomes in patients with Bloom's Syndrome occurs more frequently than normal, resulting in breaks in chromosomes and segments that have been cut and spliced between chromosomes.


Basis Facts of Disease

Bloom's syndrome is an autosomal recessive disease caused by a gene mutation. It is most common in Ashkenazi Jews, with a carrier rate of 1%. Many carriers of Bloom's syndrome have no symptoms, however if two parents are carriers of the disease, there is a 25% chance that their children will be born with Bloom's Syndrome. As long as one parent is not a carrier for Bloom's syndrome, there is a 0% chance that any children will have the disease because it is recessive.
Common Symptoms:
  • Increased susceptibility to respiratory and ear infections
  • Reduced height (under five feet)
  • Small birth sizeBloom%27s_syndrome.jpg
  • Redness on face near the nose and upper lips

  • reater cancer risk
  • Higher probability of infertility
  • Greater diabetes risk
  • High-pitched voice
A person with Bloom's Syndrome has a 20% chance of developing leukemia or lymphoma.
Frequency:
Since this syndrome was first described by New York dermatologist David Bloom in 1954, over 170 individuals have been recognized as affected.


Prognosis


Screening:
Through a blood test, it is possible to detect the specific gene change that is seen in Ashkenazi Jews with Bloom's Syndrome. The test is not as accurate for individuals who are from other ethnic backgrounds. CVS or amniocentesis, performed early during a pregnancy, can detect Bloom's Syndrome in a fetus.
Treatment:AutoRecessive.jpg
There is currently no treatment or cure for Bloom’s Syndrome, but preventative measures (avoiding sun exposure, quickly treating infections with antibiotics, and monitoring the patient for cancer) can reduce the severity of the disease. Bone marrow transplants can reduce the effects of leukemia caused by Bloom's Syndrome but growth hormone has not been shown to be effective at increasing growth in children with the disease.


Sources Cited

http://judaism.about.com/od/health/p/bloom.htm
http://www.dnadirect.com/web/article/testing-for-genetic-disorders/ashkenazi-jewish-carrier-testing/286/bloom-syndrome
http://www.mssm.edu/jewish_genetics/diseases/bloom.shtml