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Bloom Syndrome (Congenital Telangiectatic Erythema)

  • Author: Amira M Elbendary, MBBCh, MSc; Chief Editor: Dirk M Elston, MD  more...
Updated: Dec 14, 2015


Bloom syndrome (congenital telangiectatic erythema) is a rare autosomal recessive disorder. It was first described in 1954 by David Bloom in a series of patients with telangiectatic erythema on the face and dwarfism.[1] Bloom syndrome has three cardinal features: sun sensitivity, telangiectatic erythema of the face, and stunted growth.

Owing to the genomic instability present in this disease, patients with Bloom syndrome show a much higher incidence of malignant neoplasms, which is the major cause of death in such patients. No patients have been reported to reach age 50 years.

Variable degrees of immunodeficiency are present in these patients, predisposing them to various infections; this acts as an additional factor for the high incidence of cancers in Bloom syndrome patients.



Bloom syndrome (congenital telangiectatic erythema) is caused by a mutation in both alleles of the gene designated BLM, traced to band 15q26.1.[2, 3, 4, 5] BLM encodes 1417 amino acids that code for a protein in the nuclear matrix of growing cells, which is a member of the RecQ family of helicases. This protein plays a pivotal role in DNA recombination and repair. BML mutations thus result in defects in DNA repair and genomic instability in the somatic cells, predisposing the patients to cancer development.[6]

The BLM mutations can be found in compound heterozygous forms, homozygous forms, or as single gene mutation forms.

There is a 10-fold increase in the sister chromatid exchanges,[7] in addition to the presence of chromatid gaps, breaks, and gross structural rearrangements.[7, 8]

Over 60 mutations of the BLM gene have been found in Bloom syndrome. The most common mutation is the deletion of 6 nucleotides at position 2281 and their replacement with 7 others, which occurs most commonly in Ashkenazi Jews.[9]

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.[10]

MM1 and MM2 are proteins identified in Bloom syndrome and Fanconi anemia, creating a link between them. The gene encoding these proteins is FANCM. Both diseases show phenotypical similarity and both demonstrate bone marrow failure, skeletal growth deficiency, short stature, and predisposition to hematological malignancies, although they are genetically unrelated. Both diseases involve the BRAFT and FANCM complexes, which are important in DNA repair.[11, 12]

Bugreev et al suggest that a function of BLM is stimulation of RAD51 DNA pairing; results from their study show the importance of the RAD51 nucleoprotein filament conformation for stimulating DNA pairing by BLM.[13]

Photosensitivity in Bloom syndrome patients is a result of increased susceptibility to 313-nm light, approaching the ultraviolet (UV)–A range. The minimal erythema dose threshold for both UV-A and UV-B are reduced.[14] Cellular sensitivity in Bloom syndrome patients is in the form of phototoxicity and not photocarcinogenicity, as is seen in xeroderma pigmentosa.[15] Bloom syndrome patients exhibit a greater vulnerability of their DNA to UV radiation than DNA of healthy populations.

Bloom syndrome patients also demonstrate impairment in lymphocytic proliferation, deficient immunoglobulin synthesis, and lowered response to mitogen stimulation, resulting in impairment of both cellular and humoral immune responses.[16]

The overall result of the genomic instability in the proliferating cells is a high risk of malignancy, reduced fertility or infertility, B- and T-cell immunodeficiencies, and cutaneous manifestations, including photosensitivity, poikiloderma, and telangiectatic erythema.




United States

More than 170 case reports of Bloom syndrome (congenital telangiectatic erythema) have been made. The frequency of parental consanguinity is much greater than in the general population.


Bloom syndrome (congenital telangiectatic erythema) is more common in Ashkenazi Jews, with an estimated carrier frequency of 1:120 and accounting for 25% of patients in the Bloom syndrome patient registry.[17] However, it has been reported in Japan and other countries, with increased risk in cases with parental consanguinity.


Bloom syndrome (congenital telangiectatic erythema) is more common in eastern European Ashkenazi Jews.


The male-to-female ratio for Bloom syndrome (congenital telangiectatic erythema) is 1.3:1.


Bloom syndrome (congenital telangiectatic erythema) occurs in the first few months of life.

Contributor Information and Disclosures

Amira M Elbendary, MBBCh, MSc Visiting Research Fellow, Ackerman Academy of Dermatopathology; Teaching Assistant, Department of Dermatology, Kasr Alainy University Hospital, Cairo University, Egypt

Amira M Elbendary, MBBCh, MSc is a member of the following medical societies: Medical Dermatology Society, Bloom’s Syndrome Association, Egyptian Medical Syndicate, International Dermoscopy Society

Disclosure: Nothing to disclose.


Dirk M Elston, MD Professor and Chairman, Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina College of Medicine

Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Specialty Editor Board

Michael J Wells, MD, FAAD Associate Professor, Department of Dermatology, Texas Tech University Health Sciences Center, Paul L Foster School of Medicine

Michael J Wells, MD, FAAD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, Texas Medical Association

Disclosure: Nothing to disclose.

Van Perry, MD Assistant Professor, Department of Medicine, Division of Dermatology, University of Texas School of Medicine at San Antonio

Van Perry, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD Professor and Chairman, Department of Dermatology and Dermatologic Surgery, Medical University of South Carolina College of Medicine

Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology

Disclosure: Nothing to disclose.

Additional Contributors

Eleanor E Sahn, MD Director, Division of Pediatric Dermatology, Associate Professor, Departments of Dermatology and Pediatrics, Medical University of South Carolina

Eleanor E Sahn, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, Southern Medical Association

Disclosure: Nothing to disclose.


Amir A Bajoghli, MD Clinical Assistant Professor of Dermatology, George Washington University School of Medicine and Georgetown University; Chief, Dermatology and Mohs Surgery Section, Inova Fairfax Hospital; Dermatologist, Skin and Laser Surgery Center, PC

Amir A Bajoghli, MD is a member of the following medical societies: American Academy of Dermatology, American Medical Association, and Massachusetts Medical Society

Disclosure: Nothing to disclose.

  1. Bloom D. Congenital telangiectatic erythema resembling lupus erythematosus in dwarfs; probably a syndrome entity. AMA Am J Dis Child. 1954 Dec. 88(6):754-8. [Medline].

  2. Straughen J, Ciocci S, Ye TZ, et al. Physical mapping of the bloom syndrome region by the identification of YAC and P1 clones from human chromosome 15 band q26.1. Genomics. 1996 Jul 1. 35(1):118-28. [Medline].

  3. Park CJ, Ko J, Ryu KS, Choi BS. Solution structure of the RecQ C-terminal domain of human Bloom syndrome protein. J Biomol NMR. 2014 Feb. 58(2):141-7. [Medline].

  4. Kim SY, Hakoshima T, Kitano K. Structure of the RecQ C-terminal domain of human Bloom syndrome protein. Sci Rep. 2013 Nov 21. 3:3294. [Medline].

  5. Salah GB, Salem IH, Masmoudi A, Rhouma BB, Turki H, Fakhfakh F, et al. Chromosomal instability associated with a novel BLM frameshift mutation (c.1980-1982delAA) in two unrelated Tunisian families with Bloom syndrome. J Eur Acad Dermatol Venereol. 2014 Oct. 28(10):1318-23. [Medline].

  6. Payne M, Hickson ID. Genomic instability and cancer: lessons from analysis of Bloom's syndrome. Biochem Soc Trans. 2009 Jun. 37:553-9. [Medline].

  7. Seki M, Nakagawa T, Seki T, et al. Bloom helicase and DNA topoisomerase IIIalpha are involved in the dissolution of sister chromatids. Mol Cell Biol. 2006 Aug. 26(16):6299-307. [Medline].

  8. LaRocque JR, Stark JM, Oh J, Bojilova E, Yusa K, Horie K, et al. Interhomolog recombination and loss of heterozygosity in wild-type and Bloom syndrome helicase (BLM)-deficient mammalian cells. Proc Natl Acad Sci U S A. 2011 Jul 19. 108(29):11971-6. [Medline]. [Full Text].

  9. Risch N, Tang H, Katzenstein H, Ekstein J. Geographic distribution of disease mutations in the Ashkenazi Jewish population supports genetic drift over selection. Am J Hum Genet. 2003 Apr. 72(4):812-22. [Medline]. [Full Text].

  10. Nicotera TM, Notaro J, Notaro S, Schumer J, Sandberg AA. Elevated superoxide dismutase in Bloom's syndrome: a genetic condition of oxidative stress. Cancer Res. 1989 Oct 1. 49(19):5239-43. [Medline].

  11. Deans AJ, West SC. FANCM connects the genome instability disorders Bloom's Syndrome and Fanconi Anemia. Mol Cell. 2009 Dec 25. 36(6):943-53. [Medline].

  12. Guo R, Xu D, Wang W. Identification and analysis of new proteins involved in the DNA damage response network of Fanconi anemia and Bloom syndrome. Methods. 2009 May. 48(1):72-9. [Medline]. [Full Text].

  13. Bugreev DV, Mazina OM, Mazin AV. Bloom syndrome helicase stimulates RAD51 DNA strand exchange activity through a novel mechanism. J Biol Chem. 2009 Sep 25. 284(39):26349-59. [Medline]. [Full Text].

  14. Zbinden I, Cerutti P. Near-ultraviolet sensitivity of skin fibroblasts of patients with Bloom's syndrome. Biochem Biophys Res Commun. 1981 Feb 12. 98(3):579-87. [Medline].

  15. Lehmann AR, Kirk-Bell S, Arlett CF, Paterson MC, Lohman PH, de Weerd-Kastelein EA, et al. Xeroderma pigmentosum cells with normal levels of excision repair have a defect in DNA synthesis after UV-irradiation. Proc Natl Acad Sci U S A. 1975 Jan. 72(1):219-23. [Medline]. [Full Text].

  16. Hütteroth TH, Litwin SD, German J. Abnormal immune responses of Bloom's syndrome lymphocytes in vitro. J Clin Invest. 1975 Jul. 56(1):1-7. [Medline]. [Full Text].

  17. Li L, Eng C, Desnick RJ, German J, Ellis NA. Carrier frequency of the Bloom syndrome blmAsh mutation in the Ashkenazi Jewish population. Mol Genet Metab. 1998 Aug. 64(4):286-90. [Medline].

  18. Preston K. Bloom's syndrome. Australas J Dermatol. 1973 Dec. 14(3):143-50. [Medline].

  19. Passarge E. Bloom’s syndrome. German J, ed. Chromosome Mutation and Neoplasia. New York, NY: Alan R. Liss; 1983. 11–21.

  20. Vojtková J, Čiljaková M, Jeseňák M, Mišovicová N, Bánovčin P. Bloom syndrome without typical sun-sensitive skin lesions in three Slovak siblings. Int J Dermatol. 2015 Sep 4. [Medline].

  21. Bhisitkul RB, Rizen M. Bloom syndrome: multiple retinopathies in a chromosome breakage disorder. Br J Ophthalmol. 2004 Mar. 88(3):354-7. [Medline]. [Full Text].

  22. Sultan SJ, Sultan ST. Bloom syndrome in two siblings. Pediatr Dermatol. 2010 Mar-Apr. 27(2):174-7. [Medline].

  23. German J. The immunodeficiency of Bloom syndrome. Ochs HD, Smith CIE, Puck JM, eds. Primary Immunodeficiency Diseases: A Molecular and Genetic Approach. New York, NY: Oxford University Press; 1999. 335.

  24. Amor-Guéret M. Bloom syndrome, genomic instability and cancer: the SOS-like hypothesis. Cancer Lett. 2006 May 8. 236(1):1-12. [Medline].

  25. Relhan V, Sinha S, Bhatnagar T, Garg VK, Kochhar A. Bloom syndrome with extensive pulmonary involvement in a child. Indian J Dermatol. 2015 Mar-Apr. 60 (2):217. [Medline].

  26. Nair G, Lobo I, Jayalaksmi TK, Uppe A, Jindal S, Chandra A, et al. Bloom syndrome with lung involvement. Lung India. 2009 Jul. 26 (3):92-4. [Medline].

  27. Garcia AM, Salomon RN, Witsell A, Liepkalns J, Calder RB, Lee M, et al. Loss of the Bloom Syndrome helicase increases DNA ligase 4-independent genome rearrangements and tumorigenesis in aging Drosophila. Genome Biol. 2011 Dec 19. 12(12):R121. [Medline].

  28. McGowan J, Maize J, Cook J. Lupus-Like Histopathology in Bloom Syndrome: Reexamining the Clinical and Histologic Implications of Photosensitivity. Am J Dermatopathol. 2009 Oct 8. [Medline].

  29. Arora H, Chacon AH, Choudhary S, McLeod MP, Meshkov L, Nouri K, et al. Bloom syndrome. Int J Dermatol. 2014 Jul. 53(7):798-802. [Medline].

  30. Thomas ER, Shanley S, Walker L, Eeles R. Surveillance and treatment of malignancy in Bloom syndrome. Clin Oncol (R Coll Radiol). 2008 Jun. 20(5):375-9. [Medline].

  31. Chisholm CA, Bray MJ, Karns LB. Successful pregnancy in a woman with Bloom syndrome. Am J Med Genet. 2001 Aug 1. 102(2):136-8. [Medline].

  32. Kaneko H, Inoue R, Fukao T, Kasahara K, Tashita H, Teramoto T, et al. Two Japanese siblings with Bloom syndrome gene mutation and B-cell lymphoma. Leuk Lymphoma. 1997 Nov. 27(5-6):539-42. [Medline].

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