View source for Bloom syndrome

{{Short description|Genetic disorder}}
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'''Bloom syndrome''' (often abbreviated as '''BS''' in literature)<ref>{{OMIM|210900|Bloom Syndrome; BLM}}</ref> is a rare [[autosome|autosomal]] recessive [[genetic disorder]] characterized by short stature, predisposition to the development of [[cancer]], and genomic instability. BS is caused by mutations in the ''[[Bloom syndrome protein|BLM]]'' gene which is a member of the RecQ DNA [[helicase]] family. Mutations in genes encoding other members of this family, namely ''[[WRN (gene)|WRN]]'' and ''[[RECQL4]]'', are associated with the clinical entities [[Werner syndrome]] and [[Rothmund–Thomson syndrome]], respectively. More broadly, Bloom syndrome is a member of a class of clinical entities that are characterized by chromosomal instability, genomic instability, or both, and cancer predisposition.

Cells from a person with Bloom syndrome exhibit a striking genomic instability that includes excessive crossovers between homologous chromosomes and [[sister chromatid exchange]]s (SCEs). New York dermatologist Dr. David Bloom discovered and first described the condition in 1954.<ref>{{cite journal |author=Bloom D |title=Congenital telangiectatic erythema resembling lupus erythematosus in dwarfs; probably a syndrome entity |journal=American Journal of Diseases of Children |volume=88 |issue=6 |pages=754–8 |year=1954 |pmid=13206391 |doi=10.1001/archpedi.1954.02050100756008}}</ref>

Bloom syndrome has also appeared in the older literature as '''Bloom–Torre–Machacek syndrome'''.<ref name="Andrews">{{cite book |author1=James, William |author2=Berger, Timothy |author3=Elston, Dirk |title=Andrews' Diseases of the Skin: Clinical Dermatology |publisher=Saunders |year=2005 |isbn=978-0-7216-2921-6 |page=575 |edition=10th}}</ref>

==Presentation==
The most prominent feature of Bloom syndrome is proportional small size. The small size is apparent in utero. At birth, neonates exhibit rostral to caudal lengths, head circumferences, and birth weights that are typically below the third percentile.<ref>{{cite journal |last1=Keller |first1=C |display-authors=et al. |title=Growth deficiency and malnutrition in Bloom syndrome |journal=J Pediatr |date=Apr 1999 |volume=134 |issue=4 |pages=472–479 |pmid=10190923 |doi=10.1016/s0022-3476(99)70206-4 }}</ref>

The second most commonly noted feature is a rash on the face that develops early in life due to sun exposure. The facial rash appears most prominently on the cheeks, nose, and around the lips. It is described as [[erythema]]tous, which is red and inflamed, and [[telangiectasia|telangiectatic]], which is characterized by dilated blood vessels at the skin's surface. The rash commonly also affects the backs of the hands and neck, and it can develop on any other sun-exposed areas of the skin. The rash is variably expressed, being present in a majority but not all persons with Bloom syndrome, and it is on average less severe in females than in males. Moreover, the sun sensitivity can resolve in adulthood. There are other dermatologic changes, including [[Hypopigmentation|hypo-pigmented]] and hyper-pigmented areas, [[cafe-au-lait spot]]s, and [[telangiectasia]]s, which can appear on the face and on the ocular surface.{{citation needed|date=November 2020}}

There is a characteristic facial appearance that includes a long, narrow face; prominent nose, cheeks, and ears; and [[micrognathism]] or undersized jaw. The voice is high-pitched and squeaky.{{citation needed|date=September 2021}}

There are a variety of other features that are commonly associated with Bloom syndrome. There is a moderate [[immune deficiency]], characterized by deficiency in certain immunoglobulin classes and a generalized proliferative defect of [[B cell|B]] and [[T cell]]s. The immune deficiency is thought to be the cause of recurrent [[pneumonia]] and middle ear infections in persons with the syndrome.<ref>{{Cite journal|title = Bloom Syndrome: A Mendelian Prototype of Somatic Mutational Disease.|last = German|first = James M.D.|date = November 1993|journal = Medicine|doi = 10.1097/00005792-199311000-00003 |pmid = 8231788|volume=72|issue = 6|pages=393–406|s2cid = 31448222|doi-access = free}}</ref> Infants can exhibit frequent gastrointestinal upsets, with reflux, vomiting, and diarrhea, and there is a remarkable lack in interest in food. There are endocrine disturbances, particularly abnormalities of [[carbohydrate metabolism]], [[insulin resistance]] and susceptibility to [[type 2 diabetes]], [[dyslipidemia]], and compensated [[hypothyroidism]].<ref>{{cite journal |last1=Diaz |first1=A |display-authors=et al.|title=Evaluation of short stature, carbohydrate metabolism and other endocrinopathies in Bloom's syndrome |journal=Horm Res |date=Jun 9, 2006 |volume=66 |issue=3 |pages=111–117 |pmid=16763388|doi=10.1159/000093826 |s2cid=27176412 }}</ref> Persons with Bloom syndrome exhibit a paucity of subcutaneous fat. There is reduced fertility, characterized by a failure in males to produce [[spermatozoa|sperm]] (azoospermia) and premature cessation of menses (premature [[menopause]]) in females. Despite these reductions, several women with Bloom syndrome have had children, and there is a single report of a male with Bloom syndrome bearing children.<ref>{{cite journal |last1=Ben Salah |first1=G |display-authors=et al.|title=A novel frameshift mutation in BLM gene associated with high sister chromatid exchanges (SCE) in heterozygous family members |journal=Mol Biol Rep |date=Nov 2014 |volume=41 |issue=11 |pages=7373–7380 |doi=10.1007/s11033-014-3624-5 |pmid=25129257|s2cid=11074294 }}</ref>

Although some persons with Bloom syndrome can struggle in school with subjects that require abstract thought, there is no evidence that [[intellectual disability]] is more common in Bloom syndrome than in other people.{{cn|date=May 2022}}

The most serious and frequent complication of Bloom syndrome is [[cancer]]. In the 281 persons followed by the Bloom Syndrome Registry, 145 persons (51.6%) have been diagnosed with a malignant neoplasm, and there have been 227 malignancies.{{sfnp|Flanagan|Cunniff|2019}} The types of cancer and the anatomic sites at which they develop resemble the cancers that affect persons in the general population. The age of diagnosis for these cancers is earlier than for the same cancer in normal persons, and many persons with Bloom syndrome have been diagnosed with multiple cancers. The average life span is approximately 27 years. The most common cause of death in Bloom syndrome is cancer. Other complications of the disorder include [[Chronic obstructive pulmonary disease|chronic obstructive lung disease]] and type 2 diabetes.<ref name=":0">{{Cite journal|last1=Cunniff|first1=Christopher|last2=Bassetti|first2=Jennifer A.|last3=Ellis|first3=Nathan A.|date=2017|title=Bloom's Syndrome: Clinical Spectrum, Molecular Pathogenesis, and Cancer Predisposition|journal=Molecular Syndromology|language=en|volume=8|issue=1|pages=4–23|doi=10.1159/000452082|issn=1661-8769|pmid=28232778|pmc=5260600|doi-access=free}}</ref>

There are a variety of excellent sources for more detailed clinical information about Bloom syndrome.{{sfnp|Flanagan|Cunniff|2019}}

There is a closely related entity that is now referred to as Bloom-syndrome-like disorder (BSLD) which is caused by mutations in components of the same protein complex to which the ''BLM'' gene product belongs, including ''[[TOP3A]]'', which encodes the [[type I topoisomerase]], topoisomerase 3 alpha, ''[[RMI1]]'', and ''RMI2''. The features of BSLD include small size and dermatologic findings, such as cafe-au-lait spots, and the presence of the once pathognomonic elevated SCEs is reported for persons with mutations in ''TOP3A'' and ''RMI1''.<ref name=pmc5157948>{{cite journal |display-authors=1 |last1=Hudson |first1=Damien F. |last2=Amor |first2=David J. |last3=Boys |first3=Amber |last4=Butler |first4=Kathy |last5=Williams |first5=Lorna |last6=Zhang |first6=Tao |last7=Kalitsis |first7=Paul |title=Loss of RMI2 Increases Genome Instability and Causes a Bloom-Like Syndrome |journal=PLOS Genet |date=15 December 2016 |volume=12 |issue=12 |at=e1006483 |doi=10.1371/journal.pgen.1006483 |doi-access=free |pmid=27977684 |pmc=5157948}}</ref><ref>{{cite journal |vauthors=Martin CA |display-authors=et al. |title=Mutations in TOP3A Cause a Bloom Syndrome-like Disorder |journal=Am J Hum Genet |volume=103 |issue=2 |pages=221–231 |doi=10.1016/j.ajhg.2018.07.001 |pmid=30057030|pmc=6080766 |year=2018 }}</ref>

Bloom syndrome shares some features with [[Fanconi anemia]] possibly because there is overlap in the function of the proteins mutated in this related disorder.<ref name="pmid20064461">{{cite journal |vauthors=Deans AJ, West SC |title= FANCM connects the genome instability disorders Bloom syndrome and Fanconi Anemia |journal= Mol. Cell |volume= 36 |issue= 6 |pages= 943–53 |date= December 2009 |pmid= 20064461 |doi= 10.1016/j.molcel.2009.12.006 |doi-access= free }}</ref>

== Genetics ==
[[Image:Hyper sister chromatid exchanges.tiff|thumb|right|Bloom syndrome metaphase cells exhibit frequent sister chromatid exchanges.]]
Bloom syndrome is an autosomal recessive disorder, caused by mutations in the maternally- and paternally-derived copies of the gene ''BLM''.<ref>{{cite journal |vauthors=Ellis NA, Groden J, Ye TZ, Straughen J, Ciocci S, Lennon DJ, Proytcheva M, Alhadeff B, German J | year = 1995 | title = The Bloom's syndrome gene product is homologous to RecQ helicases | journal = Cell | volume = 83 | issue = 4| pages = 655–666 | doi=10.1016/0092-8674(95)90105-1 | pmid=7585968| s2cid = 13439128 | doi-access = free }}</ref> As in other autosomal recessive conditions, the parents of an individual with Bloom syndrome do not necessarily exhibit any features of the syndrome. The mutations in BLM associated with Bloom syndrome are nulls and catalytically inactive missense mutations.<ref>{{cite journal |vauthors=German J, Ciocci S, Ye TZ, Sanz MM, Ellis NA | year = 2007 | title = Syndrome-causing mutations at BLM in persons in the Bloom's Syndrome Registry | journal = Human Mutation | volume = 28 | issue = 8| pages = 743–753 | doi=10.1002/humu.20501 | pmid=17407155| s2cid = 44382072 | doi-access = free }}</ref> The cells from persons with Bloom syndrome exhibit a striking genomic instability that is characterized by hyper-recombination and hyper-mutation. Human BLM cells are sensitive to DNA damaging agents such as UV and methyl methanesulfonate,<ref name="pmid15509577">{{cite journal |vauthors=So S, Adachi N, Lieber MR, Koyama H |title=Genetic interactions between BLM and DNA ligase IV in human cells |journal=J. Biol. Chem. |volume=279 |issue=53 |pages=55433–42 |year=2004 |pmid=15509577 |doi=10.1074/jbc.M409827200 |doi-access=free }}</ref> indicating deficient repair capability.  At the level of the chromosomes, the rate of [[sister chromatid exchange]] in Bloom's syndrome is approximately 10-fold higher than normal, and quadriradial figures, which are the cytologic manifestations of crossing-over between homologous chromosomes, are highly elevated. Other chromosome manifestations include chromatid breaks and gaps, telomere associations, and fragmented chromosomes.<ref>{{cite journal | author = German J | date = Jan 1995 | title = Bloom's syndrome | journal = Dermatol Clin | volume = 13 | issue = 1| pages = 7–18 | pmid = 7712653 | doi = 10.1016/S0733-8635(18)30101-3 }}</ref> The hyper-recombination can also be detected by molecular assays <ref>{{cite journal |vauthors=Langlois RG, Bigbee WL, Jensen RH, German J | date = Jan 1989 | title = Evidence for increased in vivo mutation and somatic recombination in Bloom's syndrome | doi = 10.1073/pnas.86.2.670 | journal = Proc Natl Acad Sci U S A | volume = 86 | issue = 2| pages = 670–4 | pmid=2911598 | pmc=286535| bibcode = 1989PNAS...86..670L | doi-access = free }}</ref> The ''BLM'' gene encodes a member of the protein family referred to as [[RecQ helicase]]s. The diffusion of BLM has been measured to 1.34 <math> \tfrac{\mathrm{\mu m}^2}{\mathrm{s}} </math> in nucleoplasm and 0.13  <math> \textstyle \tfrac{\mathrm{\mu m}^2}{\mathrm{s}} </math>  at nucleoli <ref name="Bendtsen_2014">{{cite journal |author1=Kristian Moss Bendtsen |author2=Martin Borch Jensen |author3=Alfred May |author4=Lene Juel Rasmussen |author5=Ala Trusina |author6=Vilhelm A. Bohr |author7=Mogens H. Jensen | title = Dynamics of the DNA repair proteins WRN and BLM in the nucleoplasm and nucleoli | journal = European Biophysics Journal | year = 2014 | pmid = 25119658 |pmc=5576897 | doi=10.1007/s00249-014-0981-x | volume=43 |issue=10–11 | pages=509–16}}</ref> DNA helicases are enzymes that attach to DNA and temporarily unravel the double helix of the DNA molecule. DNA helicases function in DNA replication and DNA repair. BLM very likely functions in DNA replication, as cells from persons with Bloom syndrome exhibit multiple defects in DNA replication, and they are sensitive to agents that obstruct DNA replication.<ref name=":0" />

The BLM helicase is a member of a protein complex with topoisomerase III alpha, RMI1, and RMI2, also known as BTRR, Bloom Syndrome complex, or the dissolvasome.<ref>{{cite journal |last1=Bizard |first1=A. H. |last2=Hickson |first2=I. D. |title=The Dissolution of Double Holliday Junctions |journal=Cold Spring Harbor Perspectives in Biology |date=1 July 2014 |volume=6 |issue=7 |pages=a016477 |doi=10.1101/cshperspect.a016477|pmid=24984776 |pmc=4067992 }}</ref> Disruption of the proper assembly of the Bloom Syndrome complex leads to genome stability, genetic dependence on cellular nucleases GEN1 and MUS81, and loss of normal cell growth.<ref>{{Cite journal |last1=Hodson |first1=Charlotte |last2=Low |first2=Jason K. K. |last3=van Twest |first3=Sylvie |last4=Jones |first4=Samuel E. |last5=Swuec |first5=Paolo |last6=Murphy |first6=Vincent |last7=Tsukada |first7=Kaima |last8=Fawkes |first8=Matthew |last9=Bythell-Douglas |first9=Rohan |last10=Davies |first10=Adelina |last11=Holien |first11=Jessica K. |date=2022-02-08 |title=Mechanism of Bloom syndrome complex assembly required for double Holliday junction dissolution and genome stability |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=119 |issue=6 |pages=e2109093119 |doi=10.1073/pnas.2109093119 |doi-access=free |issn=1091-6490 |pmc=8832983 |pmid=35115399|bibcode=2022PNAS..11909093H }}</ref> Bloom-like phenotypes have been associated with mutations in topoisomerase III alpha, RMI1<ref>{{cite journal |display-authors=1 |last1=Martin |first1=Carol-Anne |last2=Sarlós |first2=Kata |last3=Logan |first3=Clare V. |last4=Thakur |first4=Roshan Singh |last5=Parry |first5=David A. |last6=Bizard |first6=Anna H. |last7=Leitch |first7=Andrea |last8=Cleal |first8=Louise |last9=Ali |first9=Nadia Shaukat |last10=Al-Owain |first10=Mohammed A. |last11=Allen |first11=William |last12=Altmüller |first12=Janine |last13=Aza-Carmona |first13=Miriam |last14=Barakat |first14=Bushra A.Y. |last15=Barraza-García |first15=Jimena |last16=Begtrup |first16=Amber |last17=Bogliolo |first17=Massimo |last18=Cho |first18=Megan T. |last19=Cruz-Rojo |first19=Jaime |last20=Dhahrabi |first20=Hassan Ali Mundi |last21=Elcioglu |first21=Nursel H. |last22=Gorman |first22=Gráinne S. |last23=Jobling |first23=Rebekah |last24=Kesterton |first24=Ian |last25=Kishita |first25=Yoshihito |last26=Kohda |first26=Masakazu |last27=Le Quesne Stabej |first27=Polona |last28=Malallah |first28=Asam Jassim |last29=Nürnberg |first29=Peter |last30=Ohtake |first30=Akira |last31=Okazaki |first31=Yasushi |last32=Pujol |first32=Roser |last33=Ramirez |first33=Maria José |last34=Revah-Politi |first34=Anya |last35=Shimura |first35=Masaru |last36=Stevens |first36=Paul |last37=Taylor |first37=Robert W. |last38=Turner |first38=Lesley |last39=Williams |first39=Hywel |last40=Wilson |first40=Carolyn |last41=Yigit |first41=Gökhan |last42=Zahavich |first42=Laura |last43=Alkuraya |first43=Fowzan S. |last44=Surralles |first44=Jordi |last45=Iglesais |first45=Alejandro |last46=Murayama |first46=Kei |last47=Wollnik |first47=Bernd |last48=Dattani |first48=Mehul |last49=Heath |first49=Karen E. |last50=Hickson |first50=Ian D. |last51=Jackson |first51=Andrew P. |title=Mutations in TOP3A Cause a Bloom Syndrome-like Disorder |journal=The American Journal of Human Genetics |date=August 2018 |volume=103 |issue=2 |pages=221–231 |doi=10.1016/j.ajhg.2018.07.001|pmid=30057030 |pmc=6080766 }}</ref> and RMI2 genes.<ref name=pmc5157948/>

===Relationship to cancer and aging===
As noted above, there is a greatly elevated rate of mutation in Bloom syndrome and the genomic instability is associated with a high risk of [[cancer]] in affected individuals.<ref>{{cite journal | author = German J | date = Jan 1997 | title = Bloom's syndrome. XX. The first 100 cancers | journal = Cancer Genet Cytogenet | volume = 93 | issue = 1| pages = 100–6 | doi=10.1016/s0165-4608(96)00336-6| pmid = 9062585 }}</ref> The cancer predisposition is characterized by 1) broad spectrum, including leukemias, lymphomas, and carcinomas, 2) early age of onset relative to the same cancer in the general population, and 3) multiplicity, that is, synchronous or metachronous cancers. There was at least one person with Bloom syndrome who had five independent primary cancers. Persons with Bloom syndrome may develop cancer at any age. The average age of cancer diagnoses in the cohort is approximately 26 years old.<ref name="weill.cornell.edu">{{Cite web | url=http://weill.cornell.edu/bsr/ |title = Bloom Syndrome Registry &#124; Pediatrics}}</ref>

==Pathophysiology==
When a cell prepares to divide to form two cells, the chromosomes are duplicated so that each new cell will get a complete set of chromosomes. The duplication process is called [[DNA replication]]. Errors made during DNA replication can lead to mutations. The [[Helicase|BLM protein]] is important in maintaining the stability of the DNA during the replication process. Lack of BLM protein or protein activity leads to an increase in mutations; however, the molecular mechanism(s) by which BLM maintains the stability of the chromosomes is still a very active area of research.<ref>{{Cite journal |last1=Bythell-Douglas |first1=Rohan |last2=Deans |first2=Andrew J. |date=2021-02-04 |title=A Structural Guide to the Bloom Syndrome Complex |journal=Structure |volume=29 |issue=2 |pages=99–113 |doi=10.1016/j.str.2020.11.020 |issn=1878-4186 |pmid=33357470|s2cid=229689882 |doi-access=free }}</ref>

Persons with Bloom syndrome have an enormous increase in exchange events between [[homologous chromosome]]s or [[sister chromatids]] (the two DNA molecules that are produced by the DNA replication process), and there are increases in chromosome breakage and rearrangements compared to persons who do not have Bloom's syndrome. Direct connections between the molecular processes in which BLM operates and the chromosomes themselves are under investigation. The relationships between molecular defects in Bloom syndrome cells, the chromosome mutations that accumulate in somatic cells (the cells of the body), and the many clinical features seen in Bloom syndrome are also areas of intense research.{{citation needed|date=September 2021}}
[[Image:autorecessive.svg|thumb|right|Bloom syndrome has an autosomal recessive pattern of inheritance.]]

==Diagnosis==

Bloom syndrome is diagnosed using any of three tests - the presence of quadriradial (Qr, a four-armed chromatid interchange) in cultured blood lymphocytes, and/or the elevated levels of [[sister chromatid exchange]] in cells of any type, and/or the mutation in the BLM gene. The US [[Food and Drug Administration]] (FDA) announced on February 19, 2015, that they have authorized the marketing of a direct-to-consumer genetic test from [[23andMe]].<ref name="23andmefda">{{cite web |url=https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm435003.htm |title=FDA permits marketing of first direct-to-consumer genetic carrier test for Bloom syndrome |publisher=U.S. Food and Drug Administration |access-date=19 May 2015}}</ref> The test is designed to identify healthy individuals who carry a gene that could cause Bloom Syndrome in their offspring.{{sfnp|Flanagan|Cunniff|2019}}

==Treatment==
Bloom syndrome has no specific treatment; however, avoiding sun exposure and using [[sunscreen]]s can help prevent some of the cutaneous changes associated with [[Photosensitivity|photo-sensitivity]]. Efforts to minimize exposure to other known environmental mutagens are also advisable in multiple forms.{{citation needed|date=November 2020}}

== Epidemiology ==
Bloom syndrome is extremely rare in most populations and the frequency of the disease has not been measured in most populations. However, the disorder is relatively more common amongst people of Central and Eastern European [[Ashkenazi]] Jewish background. Approximately 1 in 48,000 [[Ashkenazi Jews]] are affected by Bloom syndrome, who account for about one-third of affected individuals worldwide.<ref>{{cite journal |vauthors=Li L, Eng C, Desnick B, German J, Ellis NA | year = 1998 | title = Carrier frequency of the Bloom syndrome blmAsh mutation in the Ashkenazi Jewish population | journal = Mol Genet Metab | volume = 64 | issue = 4| pages = 286–290 | doi = 10.1006/mgme.1998.2733 | pmid = 9758720 }}</ref>

=== Bloom's Syndrome Registry ===
The Bloom's Syndrome Registry lists 283 individuals reported to have this rare disorder (as of 2020),<ref>{{Cite web |title=Bloom Syndrome - Symptoms, Causes, Treatment {{!}} NORD |url=https://rarediseases.org/rare-diseases/bloom-syndrome/ |access-date=2023-09-25 |website=rarediseases.org |language=en-US}}</ref> collected from the time it was first recognized in 1954. The registry was developed as a surveillance mechanism to observe the effects of cancer in the patients, which has shown 122<ref>{{Cite web|url = http://weill.cornell.edu/bsr/data_from_registry/|title = Data from the Bloom's Syndrome Registry, 2009|date = 2009|access-date = 17 April 2015|website = Weill Cornell Medical College|publisher = Weill Cornell Medical Center}}</ref> individuals have been diagnosed with cancer. It also acts as a report to show current findings and data on all aspects of the disorder.<ref>{{Cite journal|title = Bloom's syndrome. V. Surveillance for cancer in affected families|last1 = German|first1 = James|date = 23 April 2008|journal = Clinical Genetics|doi = 10.1111/j.1399-0004.1977.tb00919.x|pmid = 908169|last2 = Bloom|first2 = David|last3 = Passarge|first3 = Eberhard|volume=12|issue = 3|pages=162–168|s2cid = 40914579}}</ref>

==See also==
* [[Accelerated aging disease]]
* [[Bloom syndrome (gene)]]
* [[DNA repair]]
* [[Progeria]]
* [[Tumor M2-PK]]

== References ==
{{Reflist}}
* {{cite journal |vauthors=Flanagan M, Cunniff CM |title=Bloom syndrome |date=February 14, 2019 |orig-year=March 22, 2006 |veditors=Adam MP, Ardinger HH, Pagon RA |display-editors=etal |journal=GeneReviews |location=Seattle (WA) |publisher=University of Washington |pmid=20301572 |url=https://www.ncbi.nlm.nih.gov/books/NBK1398/ |access-date=July 14, 2019}}

==Further reading==
* {{cite book |editor=Margaret P Adam |editor2=Holly H Ardinger |editor3=Roberta A Pagon |editor4=Stephanie E Wallace |title=GeneReviews |publisher=University of Washington |location=Seattle (WA) |issn=2372-0697 |url=https://www.ncbi.nlm.nih.gov/books/n/gene/TOC/ |display-editors=etal|year=1993 |pmid=20301295 |last1=Adam |first1=M. P. |last2=Mirzaa |first2=G. M. |last3=Pagon |first3=R. A. |last4=Wallace |first4=S. E. |author5=Bean LJH |last6=Gripp |first6=K. W. |last7=Amemiya |first7=A. }}

== External links ==
{{Medical resources
|   DiseasesDB     = 1505
|   ICD10          = {{ICD10|Q|82|8|q|82}}
|   ICD9           = {{ICD9|757.39}}
|   OMIM           = 210900
|   MedlinePlus    =
|   eMedicineSubj  = derm
|   eMedicineTopic = 54
|   MeshID         = D001816
|  GeneReviewsNBK  = NBK1398
|  GeneReviewsName = Bloom's Syndrome
| Orphanet=125
}}
* {{NLM|bloomsyndrome}}

{{Congenital malformations and deformations of integument}}
{{DNA repair-deficiency disorder}}
{{Progeroid syndromes}}

[[Category:Chromosome instability syndromes]]
[[Category:Genodermatoses]]
[[Category:Autosomal recessive disorders]]
[[Category:Rare syndromes]]
[[Category:Ashkenazi Jews topics]]
[[Category:IUIS-PID table 3 immunodeficiencies]]
[[Category:DNA replication and repair-deficiency disorders]]
[[Category:Progeroid syndromes]]
[[Category:Syndromes with tumors]]
[[Category:Syndromes affecting stature]]
[[Category:Diseases named after discoverers]]