What are the other Names for this Condition? (Also known as/Synonyms)

• Bloom-Torre-Machacek Syndrome
• Congenital Telangiectatic Erythema
• Growth Deficiency, Sun-Sensitive, Telangiectatic, Hypo and Hyperpigmented Skin, Predisposition to Malignancy and Chromosomal Instability

What is Bloom Syndrome? (Definition/Background Information)

• Bloom Syndrome (BLS or BS) is a disorder characterized by a significantly increased risk of cancer and various other features
• Signs and symptoms include short stature; sun-sensitive skin changes on the face, hands and/or arms; a high-pitched voice; and distinctive facial features including a long, narrow face, small lower jaw, large nose and prominent ears
• Some affected individuals may also have learning disabilities; an increased risk of diabetes; chronic obstructive pulmonary disease (COPD); and recurrent infections of the upper respiratory tract, ears, and lungs during infancy
• Cancers may include any of those found in the general population, but develop much earlier in life in affected individuals
• It is caused by mutations in the BLM gene and is inherited in an autosomal recessive manner
• Treatment is generally symptomatic and supportive

(Source: Bloom Syndrome; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Who gets Bloom Syndrome? (Age and Sex Distribution)

• Bloom Syndrome is a rare congenital disorder. The presentation of symptoms may occur at birth
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Bloom Syndrome? (Predisposing Factors)

• A positive family history may be an important risk factor, since Bloom Syndrome is an inherited condition
• Currently, no other risk factors have been clearly identified for the disorder

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Bloom Syndrome? (Etiology)

• The exact cause of development of Bloom Syndrome is presently unknown
• It is a genetic disorder involving the BLM gene that is transmitted in an autosomal recessive manner

Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents have an autosomal recessive condition, there is a 100% likelihood of passing on the mutated genes to their children. If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children born to two carriers, have a 25% chance of being homozygous dominant (unaffected), a 50% chance of being heterozygous (carrier), and a 25% chance of being homozygous recessive (affected).

What are the Signs and Symptoms of Bloom Syndrome?

The signs and symptoms of Bloom Syndrome may include:

• Agenesis of maxillary lateral incisor
• Bronchiectasis
• Cafe-au-lait spot
• Chronic lung disease
• Clinodactyly of the 5th finger      
• Cryptorchidism
• Hypertrichosis   
• Leukemia
• Prominent nose
• Specific learning disability
• Spotty hypopigmentation
• Syndactyly
• Type II diabetes mellitus

Based on the frequency of symptoms observed, the following information may be noted:

Very frequently present symptoms in 80-99% of the cases:

• Abnormality of chromosome stability
• Delayed skeletal maturation
• Diarrhea
• Dolichocephaly
• Erythema
• Facial telangiectasia in butterfly midface distribution
• Intrauterine growth retardation
• Malar flattening
• Narrow face
• Postnatal growth retardation
• Recurrent respiratory infections
• Sinusitis
• Spotty hyperpigmentation

Frequently present symptoms in 30-79% of the cases:

• Cutaneous photosensitivity
• High pitched voice 
• Hypoplasia of the zygomatic bone 
• Short nose

Occasionally present symptoms in 5-29% of the cases:

• Acute leukemia 
• Azoospermia
• Decreased fertility in females
• Finger syndactyly 
• Hand polydactyly 
• Hyperhidrosis
• Hypopigmented skin patches
• Ichthyosis 
• IgA deficiency     
• IgG deficiency   
• IgM deficiency 
• Intellectual disability, mild
• Lymphoma 
• Microcephaly
• Neoplasm of the gastrointestinal tract    
• Protruding ear
• Reduced number of teeth
• Sacral dimple
• Squamous cell carcinoma

(Source: Bloom Syndrome; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How is Bloom Syndrome Diagnosed?

Bloom Syndrome is diagnosed by either cytogenetic analysis or mutation testing.

• Cytogenetic analysis is used to detect if there is an increased amount of sister chromatid exchange in cells
• Genetic testing can reveal if a person has mutations in the BLM gene, which are known to cause Bloom Syndrome
• If an individual has a family history of Bloom syndrome, one of these two testing methods may be used to find out if the person has also inherited the condition
• An unusually low birth weight and short height throughout childhood are suggestive of Bloom syndrome in an individual with an affected sibling

(Source: Bloom Syndrome; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Bloom Syndrome?

The complications of Bloom Syndrome may include:

• Increased susceptibility of leukemia and lymphoma
• Upper respiratory infections and diseases

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Bloom Syndrome Treated?

There is currently no cure for Bloom Syndrome, so treatment is generally symptomatic and supportive.

• Because affected individuals are hypersensitive to DNA-damaging chemicals and ionizing radiation, standard cancer treatment plans often need to be adjusted for affected individuals
• Changes may include reducing both the dosage and duration of the treatment; however, the cancers in affected individuals are often unusually responsive to treatment. The wide variety of types of cancer as well as the early development of tumors in affected individuals make life-long cancer surveillance significantly important
• Additionally, it is recommended that individuals avoid sun exposure to the face, particularly in infancy and early childhood
• Treatment of diabetes is typically the same as for individuals in the general population.

(Source: Bloom Syndrome; Genetic and Rare Diseases Information Center (GARD) of National Center for Advancing Translational Sciences (NCATS), USA.)

How can Bloom Syndrome be Prevented?

Currently, Bloom Syndrome may not be preventable, since it is a genetic disorder.

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders

Regular medical screening at periodic intervals with tests and physical examinations are recommended.

What is the Prognosis of Bloom Syndrome? (Outcomes/Resolutions)

• The prognosis of Bloom Syndrome is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications
• Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Bloom Syndrome:

The following DoveMed website link is a useful resource for additional information:

http://www.dovemed.com/diseases-conditions/rare-disorders/