How is beta thalassemia diagnosed prenatally?

Updated: Dec 19, 2018
  • Author: Pooja Advani, MD; Chief Editor: Emmanuel C Besa, MD  more...
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Answer

Prenatal diagnosis is possible through analysis of DNA obtained via chorionic villi sampling at 8-10 weeks’ fetal gestation or by amniocentesis at 14-20 weeks’ gestation. In most laboratories, the DNA is amplified using PCR and then is analyzed for the presence of the thalassemia mutation using a panel of oligonucleotide probes corresponding to known thalassemia mutations.

Since the genetic defects are quite variable, family genotyping usually must be completed for diagnostic linkage (segregation) analysis. With the anticipated availability of large-scale mutation screening by DNA chip technology, extensive pedigree analyses may be obviated.

Physicians can perform fetal blood sampling for Hb chain synthesis at 18-22 weeks’ gestation, but this procedure is not as reliable as DNA analysis sampling methods. Genetic therapy strategies are currently in the early stages of development.


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