The IVS-II-1 (G-->a) beta0-thalassemia mutation in cis with HbA2-Troodos [delta116(G18)Arg-->Cys (CGC-->TGC)] causes a complex prenatal diagnosis in an Iranian family.
The beta-thalassemia (thal) minor phenotypes with normal Hb A2 levels and decreased MCV and MCH values are relatively rare beta-thal traits. Here, we describe a family with normal Hb A2 and decreased MCV and MCH levels. Amplification refractory mutation system-polymerase chain reaction (ARMS-PCR) revealed the IVS-II-1 (G-->A) mutation in the beta-globin gene of the proband and her father. Direct sequencing of the gamma-globin gene of the proband and her father also revealed a previously reported variant called Hb A2-Troodos [gamma116(G18)Arg-->Cys] [in cis with the IVS-II-1 (G-->A) beta0-thal mutation]. This is the first case report of Hb A2-Troodos in association with the beta0 IVS-II-1 mutation. Reduced Hb A2 expression by a concomitant Hb A2 beta-thal in cis or trans, may cause problems in carrier diagnostics, and eventually in genetic counseling and prenatal diagnosis when insufficient molecular analyses are performed.
Eram
S Mohammad
SM
Medical Genetics Laboratory of Dr. Zeinali, Tehran, Iran.
Azimifar
Babak
B
Abolghasemi
Hassan
H
Foulady
Panty
P
Lotfi
Vida
V
Masrouri
Maryam
M
Hosseini
Maesomeh
M
Abdolhosseini
Afsaneh
A
Zeinali
Sirous
S
D000328:Adult; D004909:Erythrocyte Indices; D005192:Family Health; D005260:Female; D006443:Hemoglobin A2 / Q000235:genetics*; D006455:Hemoglobins, Abnormal / Q000235:genetics*; D006801:Humans; D007492:Iran; D017354:Point Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D011247:Pregnancy; D011296:Prenatal Diagnosis; D017086:beta-Thalassemia / Q000235:genetics*
D006455:Hemoglobins, Abnormal; C508163:hemoglobin A2-Troodos; D006443:Hemoglobin A2