Bloom Syndrome (Congenital Telangiectatic Erythema) Workup

Updated: Apr 15, 2019
  • Author: Amira M Elbendary, MBBCh, MSc; Chief Editor: Dirk M Elston, MD  more...
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Workup

Approach Considerations

Bloom syndrome should be suspected if any of the clinical or cytogenetic criteria described below are found. [47]

Clinical findings are as follows:

  • Prenatal-onset retarded growth that usually includes weight gain, linear growth, and head circumference and that persists into infancy, childhood, and adulthood
  • Moderate-to-severe growth retardation together with photosensitive erythematous rash that commonly involves the face in a butterfly distribution
  • Moderate-to-severe growth retardation and an early diagnosis of cancer

Cytogenetic findings are as follows:

  • Increased numbers of sister-chromatid exchanges
  • Increased quadriradial configurations (Qrs) in cultured blood lymphocytes
  • Chromatid gaps, breaks, and rearrangements
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Laboratory Studies

The diagnosis of Bloom syndrome (congenital telangiectatic erythema) can be confirmed or excluded by a laboratory test known as a chromosome study; blood and skin cells show a characteristic pattern of chromosome breakage and rearrangement. Testing for chromosome instability, including the presence of quadriradicals and increased sister chromatid exchanges, is performed at the US National Institutes of Health and US Armed Forces Institute of Pathology laboratories.

Prenatal diagnosis

Prenatal diagnosis of Bloom syndrome is possible with amniocentesis for amniotic fluid cell culture to assess for a high number of sister chromatid exchanges; DNA analysis will be available in the near future.

Genetic screening and counseling

Genetic screening is recommended for populations at high risk for being a carrier of the disease, such as Ashkenazi Jews. Targeted mutation analysis and polymerase chain reaction (PCR) to examine the DNA for the BLM 6-deletion/7-insertion mutation should be performed.

Genetic counseling could be offered to parents of patients with Bloom syndrome. Being an autosomal recessive disease in its mode of transmission, the risk of having the disease in siblings of heterozygous carriers is estimated to be 25%. [48]

Screening for complications

Immunoglobulin levels should be checked; decreased immunoglobulin A and immunoglobulin M, with or without immunoglobulin G changes, are expected.

There is no consensus regarding cancer surveillance in Bloom syndrome patients. The most important recommendation is to observe Bloom syndrome patients for any signs and symptoms that warrant further investigations (eg, complete blood cell count with any constitutional symptoms). Unintentional weight loss should be investigated thoroughly. Screening colonoscopy could be considered from age 16 years and carried out regularly, but there is no consensus for the appropriate interval. [38]

Periodic evaluation for leukemia and early screening for breast, cervical, and colorectal cancers are recommended. MRI and ultrasonography are recommended rather than other radiologic diagnostic modalities, in order to minimize the exposure to radiation in such vulnerable patients.

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Other Tests

See the Workup section in the Medscape article Short Stature for detailed information on the workup for short stature.

Evaluation of children with photosensitivity

Phototesting and photopatch testing could be performed. Screening for antinuclear antibodies (ANA) and performing a porphyrin profile to exclude the possibility of lupus erythematosus or erythropoietic porphyria may be warranted.

Skin biopsy

Histopathologic findings from skin biopsies taken from the erythematous lesions show a lupuslike picture: follicular plugging, interface dermatitis, monocellular infiltrate, and perivascular infiltrate. However, the presence of changes in the basement membrane, periadnexal lymphocytic infiltration, and dermal mucin are very rare. [46] Bandlike dense lymphoid infiltrates with epidermotropism, resembling mycosis fungoides, have been reported.

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