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= Bloom Syndrome =

Genetics
Bloom syndrome is inherited through an autosomal recessive pattern, meaning that both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition both carry one copy of the mutated gene. However, the parents typically do not show signs of symptoms of the condition. Because the gene does not function properly, this creates an unusually high number of breaks or instability along their chromosomes. Mutations in the BLM gene are what causes Bloom syndrome. The BLM gene is responsible for making a member of the protein family known as RecQ helicases. Helicases are enzymes that attach to DNA and temporarily unravel the double helix of the DNA molecule. This unraveling is essential for DNA replication in preparation for cell division and for the repair of the damaged DNA molecule. RecQ helicases maintain the structure of the DNA so therefore they are commonly known as ‘caretakers of the genome.’

Prognosis
Blood syndrome is an extremely rare disorder in most populations and the frequency of the disease still remains unknown. However, the disorder is most common amongst people of Central and Eastern European (Ashkenazi) Jewish background. Approximately 1 in 50,000 people infected with Bloom syndrome and about one-third of people whom have Bloom syndrome are of Ashkenazi Jewish descent.

Symptoms
Symptoms of Bloom syndrome include short stature, sun-sensitive skin changes, an increased risk for cancer, and other health complications. People born with Bloom syndrome are usually born with low birth weight and length. When they are finished growing in adulthood, they are usually less than 5 feet tall. Individuals with Bloom syndrome usually develop dilated blood vessels and have reddening of the skin, mostly from sun exposure. The reddened skin usually is across the nose and cheeks and can sometimes affect the hands and arms. They also usually develop a high-pitch voice, and distinctive facial features including a long, narrow face, small lower jaw, large nose, and prominent ears. Affected individuals have an increased risk of cancer and can develop any of the cancers that are within the general population. However, people with Bloom syndrome can develop more than one cancer and unusually do so early on in their life. People with Bloom syndrome are also at high risk for learning disabilities, diabetes, chronic obstructive pulmonary disease (COPD), and recurrent infections of the ears, lungs, and upper respiratory tract during infant years. A structural chromosome abnormality and an increased incidence of leukemia are associated. Men with Bloom syndrome usually are unable to produce sperm, therefore they are infertile and women generally have reduced fertility and experience menopause at an earlier age.

Treatment
There are no specific treatments available at the moment, however, people affected by Bloom syndrome can be advised to avoid sun exposure and to use sunscreen as often as possible when going outside to help prevent some of the sun-sensitive skin changes and skin lesions. Children with Bloom syndrome need nutritional monitoring to ensure maximum growth. Experiments of growth hormones for patients with Bloom syndrome have been highly unsuccessful. Affected individuals should be screened regularly for cancer and because of sensitivity to radiation and DNA-damaging chemicals; most standard cancer treatments need modification.