What is the role of genetic polymorphisms in the etiology of factor XIII (FXIII) deficiency?

Updated: Aug 01, 2019
  • Author: Robert A Schwartz, MD, MPH; Chief Editor: Perumal Thiagarajan, MD  more...
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Genetic polymorphisms affecting both the A and B subunits have been reported, but because they do not involve conserved amino acids or are not important for protein structure, they do not result in FXIII deficiency and bleeding. Based on an analysis of polymorphisms in the gene for FXIII subunit A and their products in a northern Portuguese population, it has been stated that the evolutionary order of appearance of the main protein alleles for FXIII is 1B-->2B-->1A-->2A and that intragenic combinations are likely to have played a role in the molecular diversity in the main FXIII subunit A alleles. [85]

Genetic polymorphisms and, particularly, intragenic polymorphisms are useful in genetic counseling of families with unknown mutations. For example, 80% of whites are heterozygous for a tetrameric repeat in intron 1 of subunit A, which can help differentiate defects in subunit A from defects in subunit B. [10, 11, 75, 5] Some polymorphisms are universal, while others appear to be restricted to particular ethnic groups. The latter situation will change as ethnic intermarriages increase in this global society. Families with severe FXIII deficiency associated with a serious disabling bleeding disorder have access to all of the genetic tools available to patients with hemophilia A and B.

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