A novel polymorphism causes a different restriction pattern by RsaI in the beta-globin gene cluster: application in prenatal diagnosis.
beta-Thalassemia (beta-thal) is a major health problem in Iran and the incidence of carriers is around 3-4%. The disease is caused by heterogeneous mutations in the beta-globin gene and is characterized by hypochromic microcytic anemia. The human beta-globin complex spans a region of 70 kb and contains over 20 restriction fragment length polymorphisms (RFLPs). At least nine RFLP markers including RsaI/beta in the beta-globin gene cluster have been routinely exploited for prenatal diagnosis. Here, we report a novel polymorphism upstream of the beta-globin gene characterized by RsaI digestion. Sequencing of a fragment containing this area showed a nucleotide change (T>C) at position -223 upstream of the beta-globin gene. This change could interfere with precise interpretation of the RsaI digestion pattern in linkage analysis and prenatal diagnosis of beta-thal.
Valaei
Atefeh
A
National Reference Centre For Prenatal Diagnosis of Thalassaemia and Haemoglobinopathies, Pasteur Institute of Iran, Tehran, Iran 13164.
Bayat
Fatemeh
F
Kordafshari
Alireza
A
Zeinali
Sirous
S
Karimipoor
Morteza
M
D015252:Deoxyribonucleases, Type II Site-Specific; D005192:Family Health; D006453:Hemoglobinopathies / Q000175:diagnosis / Q000235:genetics*; D006455:Hemoglobins, Abnormal / Q000235:genetics; D006801:Humans; D007492:Iran / Q000453:epidemiology; D017354:Point Mutation; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D011296:Prenatal Diagnosis / Q000379:methods*; D055544:beta-Globins / Q000235:genetics*
D006455:Hemoglobins, Abnormal; D055544:beta-Globins; D015252:Deoxyribonucleases, Type II Site-Specific; C040158:GTAC-specific type II deoxyribonucleases