Bloom’s syndrome is a rare genetic disorder in which the cell’s ability to maintain the integrity of DNA is impaired. This DNA instability is displayed at the chromosome level as striking increases in exchanges between chromosomes, as well as increases in chromosome gaps and breaks. The syndrome is inherited in an autosomal recessive manner, wherein both the maternally- and paternally-derived copies of the Bloom’s syndrome gene (BLM) are functionally deficient.
Bloom's syndrome is characterized by unusually small size, sensitivity to sunlight, immune-system deficiencies, and an extraordinarily high risk for developing cancer—of any type—beginning early in life. Other clinical features include chronic respiratory illness, recurrent ear infections, and diabetes. Males are infertile; females enter menopause prematurely. There are fewer than 300 known surviving cases of Bloom's syndrome worldwide. Lifespan is limited; the average age of death is 27 years. The most common cause of death is from cancer.