What causes Bloom syndrome and who gets it?
Bloom syndrome is an autosomal recessive inherited disorder, which means that two abnormal Bloom’s syndrome genes are needed for the disease to be apparent (one from each parent). If a person has one affected gene, he or she is called a carrier of Bloom Syndrome and does not manifest symptoms of the disease. If both parents are carriers, there is a 1 in 4 chance of having an affected child with each pregnancy. The gene for Bloom syndrome is located on chromosome 15 (gene locus is band 15q26.1). Mutations in this gene cause errors in the copying process during DNA replication and result in a higher number of chromosome breakages and rearrangements. This leads to the signs and symptoms of Bloom syndrome. Bloom syndrome is more common in eastern European Ashkenazi Jews. At least 1 in 100 Ashkenazi Jews is a carrier of the disease. It appears to be slightly more common in males than females.
