Excerpt from Bloom Syndrome (Congenital Telangiectatic Erythema)

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Background

Bloom syndrome is a rare autosomal recessive disorder characterized by telangiectases and photosensitivity, growth deficiency of prenatal onset, variable degrees of immunodeficiency, and increased susceptibility to neoplasms of many sites and types. The New York dermatologist David Bloom first described the syndrome in 1954.

Pathophysiology

The syndrome is caused by a mutation in the gene designated BLM, traced to band 15q26.1. The protein encoded by the normal gene has DNA helicase activity and functions in the maintenance of genomic stability. Increased sister chromatid exchanges and chromosomal instability also occur, which is assumed to be responsible for the phenotype and the cancer predisposition. In 1989, Nicotera et al suggested that the major biochemical defect in persons with Bloom syndrome is chronic overproduction of the superoxide radical anion. They thought that inefficient removal of peroxide might be responsible for the high rates of sister chromatid exchange and chromosomal damage in Bloom syndrome cells.

Frequency

United States

More than 170 case reports have been made. The frequency of parental consanguinity is much greater than in the general population.

International

The disease is more common in Ashkenazi Jews but has been reported in Japan and other countries.

Mortality/Morbidity

Early diagnosis of leukemia is, at present, not known to improve the chances of curative therapy. Frequent hematologic examinations in children is not advised for fear of untoward psychologic effects. Allogeneic marrow grafting has not been performed in Bloom syndrome patients. Men with Bloom syndrome are sterile; women have reduced fertility and a shortened reproductive span. Bloom syndrome patients who become pregnant are at high risk for premature delivery. Intelligence is usually normal, although mild deficiency has occurred in a few affected persons. Diabetes occurs in approximately 10% of individuals with Bloom syndrome.

Race

Bloom syndrome is more common in eastern European Ashkenazi Jews.

Sex

The male-to-female ratio is 1.3:1.

Age

This condition occurs in the first few months of life.

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