Double Heterozygous of alpha trait & Beta trait

Hi Andy, I have read somewhere that when a preson is " Double Heterozygous of alpha trait & Beta trait ", the red blood cell indices MCV, MCH, HB A2 can sometimes be normalised. Do you of any idea on that ?

I have also read that "Double Heterozygous of alpha trait & Beta trait" would result in Normalised HBA2 value but MCV & MCH would still be decreased ? Which is true ? Will the MCV & MCH be normal or decreased in the case of Double Heterozygous of alpha trait & Beta trait. I understand this Double Heterozygous traits has a high occurrance rate in South East Asia.

The presence of double heterozygous alpha- and beta-thalassemia makes diagnosis very difficult, as it is possible to have balanced hemoglobin as a result. DNA analysis is the only solution.

http://content.karger.com/ProdukteDB/produkte.asp?Aktion=ShowAbstract&ArtikelNr=69539&Ausgabe=229060&ProduktNr=224224

Conclusion: Molecular analysis must be used for the accurate diagnosis of double heterozygous alpha- and beta-thalassaemia for proper risk ascertainment, especially in regions with a high prevalence of both types of thalassaemia.

You are demographically in both risk groups.

Hi Andy, I am not a member and has no access to the full text of the study.

I have read that " double heterozygous alpha- and beta-thalassemia" would result in normalised HbA2 but really have no idea on its effects on MCV & MCH. Have you any idea on that ?

Incidentally I have read both my parents Full Blood Count reports. Both of them have ref-range MCV & MCH. They have not done any HB Electropherisis though.

MCV and MCH would likely be slightly lower than normal. A review of an affected family can be read at http://www.encyclopedia.com/doc/1G1-165166826.html

Except for mild reduction in the MCV and MCH, both parents are phenotypically normal, with [alpha]-thalassemia genotype of -[alpha]/[alpha][alpha] indicating the loss of a single [alpha]-gene. Both parents also are heterozygotes for the [[beta].sup.+] IVS1-6 mutation, which is of mild severity, thus, the ameliorating effect resulting from the interaction between these two mutations in heterozygotes might explain the borderline Hb A2 levels (Mother Hb A2 = 3.7%, Father Hb A2 = 4.1%). It has been suggested that the levels of Hb A2 in [alpha]-thalassemia are lower than in normal individuals, (12) raising the possibility that the level may be lower in double heterozygotes for [alpha] and [beta]-thalassemia than in those with [beta]-thalassemia alone.

Their children ranged from alpha carrier to beta major, even though both parents appeared to be normal.

Thanks Andy.

Just to share, I have found this webpage which is very informative for Thalassemia Prevention.

http://www.thalassaemia.org.cy/MyData/prevention2.pdf

It does however say that concurrent alpha and beta thal carrier has a ameliorating effects on the red cell indices amid usually to borderline and sometimes normal.

Some of the silent Beta mutations listed there with typical Red cell indices does indicate that it is almost impossible to detect them other than using DNA method.

Hi Daddy123

That was a very informative link, thanks for sharing

Manal