What Your Test Results Mean:

Carriers typically show no symptoms of Bloom syndrome; however, carriers are at an increased risk of having a child with Bloom syndrome. Risk for the current or future pregnancies is dependent on your partner’s carrier status.

Disease Explained:

Bloom syndrome is an inherited disorder characterized by proportionate short stature from the prenatal period to adulthood. Other features are variable from individual to individual and may include learning disabilities, sensitivity to the sun, gastroesophageal reflux, recurrent ear and lung infections, infertility in males, and an increased risk for cancer. Individuals with Bloom syndrome are not able to maintain the stability of genetic material in their bodies due to the defect in the BLM gene. The cause of the main features of Bloom syndrome are not known; however, the instability of genetic material is associated with cancer predisposition.

Treatment of individuals with Bloom syndrome is symptomatic. Individuals with Bloom syndrome should avoid sun exposure and undergo increased surveillance for cancer starting in childhood as cancer is the greatest cause of death in individuals with Bloom syndrome. Lifespan is variable but is typically decreased in individuals with a cancer diagnosis.

How the Genetics Works:

The clinical features of Bloom syndrome are caused by pathogenic variants in the BLM gene. Individuals have two copies of the BLM gene. Carriers of Bloom syndrome have a single variant in BLM while individuals with Bloom syndrome have variants in both copies of BLM, one inherited from each parent.