Question of the Week

Question :

Posted On : 19 Aug 2004

If parents are sickle trait or thalessemia minor what antenatal screening can be done?

Expert Answer :

No expert answer available.

Answer Discussion :

Pediatric Oncall

For thalassemia major, until the development of DNA techno-logies, prenatal diagnosis was carried out by estimating the rate of globin chain synthesis in fetal blood samples and it is still a method of choice where DNA mutations are unidenti-fied in parents, or when the couples report for the first time with advanced pregnancy. In this procedure fetal blood sample is collected after 18 weeks of gestation and globin chains are separated.

DNA analysis can be done by offering prenatal diagnosis to the couples. It is essential to characterize the DNA mutations of the parents. Fetal DNA analysis could be done by extracting DNA from amniotic fluid after 15 weeks of gestation and chorionic villus samples {CVS} between 10-12 weeks or later gestation.

For sickle cell anemia, the discovery of the linkage between the HbS gene and restriction endonuclease polymorphism enables the diagnosis to be made prenatal by analyzing genomic DNA of fetal cells obtained by amniocentesis. This procedure carries only a 0,5 Percent fetal risk. There are two main laboratory test performed on the amniotic fluid obtained:

Polymerase Chain Reaction {PCR} Plus Enzyme detection of the mutation

Polymerase Chain Reaction Plus Oligonucleid hybridization

20 years ago

Yael

amniotic villous sampling?

20 years ago

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