What is Bloom Syndrome, Causes and Symptoms of Bloom Syndrome

Bloom Syndrome

  • Posted on- May 28, 2018
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Bloom Syndrome

Bloom Syndrome is a disorder that is characterized by a significantly increased risk of cancer and various other features.

Signs and symptoms of bloom Syndrome involves short stature sun-sensitive skin changes on the face, hands 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 can 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.

What are the causes of Bloom Syndrome?

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: The conditions of autosomal recessive 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.

The individual will be a carrier of the condition if only one mutant copy of the gene is inherited, 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
  • Chronic lung disease
  • Clinodactyly of the 5th finger     
  • Cryptorchidism
  • Hypertrichosis  
  • Leukemia
  • Prominent nose
  • Specific learning disability
  • Spotty hypopigmentation
  • 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


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.


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