Delta-beta thalassemia

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Delta-beta thalassemia
Delta Beta Thalassemia.jpg
Delta-beta thalassemia
Specialty Hematology   OOjs UI icon edit-ltr-progressive.svg
Causes Produces only gamma-globin and forms HbF(deletes entire delta and beta gene sequence) [1]
Diagnostic method High-performance liquid chromatography
TreatmentBlood transfusions [2]

Delta-beta thalassemia is a rare form of thalassemia in which there is a reduced production of hemoglobin subunit delta and hemoglobin subunit beta and raised levels of hemoglobin subunit gamma. It is an autosomal recessive disorder. [1] [3]

Contents

Signs and symptoms

An individual with delta-beta thalassemia is usually asymptomatic, however microcytosis can occur where the red blood cells are abnormally small. [1] [4]

Mechanism

Structure of hemoglobin the proteins a and b subunits are in red and blue, 1GZX Haemoglobin.png
Structure of hemoglobin the proteins α and β subunits are in red and blue,

Delta-beta thalassemia is autosomal recessive disorder, [1] which means both parents are affected and two copies of the gene must be present. [5] A carrier gets a normal gene to produce hemoglobin A, from one parent and the other parent supplies a gene which makes no hemoglobin A. [6] Delta-beta thalassemia is considered rare. [2]

Delta-beta-thalassemia is caused by deletions of the entire delta and beta genes sequences and only gamma-globin and HbF are formed. Rarely, non-deletional forms have been reported. [7] [8]

When two delta0 mutations are inherited, no hemoglobin A2 (alpha2, delta2) are formed. This is innocuous because only 2-3% of normal adult hemoglobin is hemoglobin A2. The individual will have normal hematological parameters (erythrocyte count, total hemoglobin, mean corpuscular volume).[ medical citation needed ] The delta-beta thalassemia demonstrates one mutation is at the +69 position. [9]

Relation to beta thalassemia

Delta-beta thalassemia can mask the diagnosis of beta thalassemia trait. In beta thalassemia, an increase in hemoglobin A2 results, but the co-existence of a delta-beta thalassemia mutation will decrease the value of the hemoglobin A2 into the normal range, thereby obscuring the diagnosis of beta thalassemia trait [10]

Diagnosis

Following the detection of hypochromic microcytic red blood cells, delta-beta thalassemia is confirmed by high-performance liquid chromatography. [11]

Treatment

When needed, treatment for anemia, such as blood transfusions are used. [2]

Stem cell transplant is another option, but the donor and the individual who will receive the bone marrow transplant must be compatible, the risks involved should be evaluated. [2] [12] [13]

See also

References

  1. 1 2 3 4 "Delta-beta-thalassemia". Orphanet. Retrieved 16 September 2016.
  2. 1 2 3 4 "Thalassaemia | Health | Patient". Patient. Retrieved 17 September 2016.
  3. ↑ "HBD - hemoglobin subunit delta". Orphanet. Archived from the original on 18 September 2016. Retrieved 17 September 2016.
  4. ↑ Pal, G. K. & (2005). Textbook Of Practical Physiology - 2Nd Edn. Orient Blackswan. p. 53. ISBN   9788125029045 . Retrieved 17 September 2016.
  5. ↑ "Autosomal recessive: MedlinePlus Medical Encyclopedia". medlineplus.gov. Retrieved 17 September 2016.
  6. ↑ "Delta beta thalassemia carrier" (PDF). Public Health England. Archived from the original (PDF) on 24 September 2016. Retrieved 17 September 2016.
  7. ↑ "Transcription and Translation - National Human Genome Research Institute (NHGRI)". www.genome.gov. NIH. Retrieved 17 September 2016.
  8. ↑ Proytcheva, Maria, ed. (2010). Diagnostic pediatric hematopathology. Cambridge: Cambridge University Press. p. 61. ISBN   9780521881609 . Retrieved 17 September 2016.
  9. ↑ "OMIM Entry - * 142000 - HEMOGLOBIN--DELTA LOCUS; HBD". www.omim.org. Retrieved 17 September 2016.
  10. ↑ Galanello, Renzo; Origa, Raffaella (2010). "Beta-thalassemia". Orphanet Journal of Rare Diseases. 5 (1): 11. doi: 10.1186/1750-1172-5-11 . ISSN   1750-1172. PMC   2893117 . PMID   20492708.
  11. ↑ Ahmad SQ, Zafar SI, Malik HS, Ahmed S (November 2017). "Delta-Beta Thalassaemia in a Pathan Family". Journal of the College of Physicians and Surgeons (Pakistan). 27 (11): 722–724. PMID   29132487.
  12. ↑ Cao, Antonio; Galanello, Renzo (2010-02-01). "Beta-thalassemia". Genetics in Medicine. 12 (2): 61–76. doi: 10.1097/GIM.0b013e3181cd68ed . ISSN   1098-3600. PMID   20098328.
  13. ↑ "Risks". nhs.uk. Retrieved 2018-04-28.

Further reading

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