title: Frequency of beta-thalassemia or beta-hemoglobinopathy carriers simultaneously affected with alpha-thalassemia in Iran.
abstract: BACKGROUND
  Beta-thalassemias are prevalent heritable single gene disorders affecting the quantity of the hemoglobin molecule. Rarely, a co-inheritance of these impairments with alpha-thalassemia and/or a hemoglobinopathy occurs and makes an important double heterozygote or homozygous state. Thus finding these cases is essential for genetic counseling. The present study aimed to identify the prevalence of coexistent alpha-thalassemia mutations, hemoglobinopathies, and beta-thalassemia determinants.
  
  
  METHODS
  This descriptive study was performed on 5760 patients. We used complete blood cell count, Hb electrophoresis, and HbA2 measurement for thalassemia carrier identification. Increased HbA2 (> or = 3.5%) is the standard diagnostic marker for beta-thalassemia, while normal HbA2 with low MCH and MCV can indicate an alpha-thalassemia carrier or atypical beta-thalassemia minor. Individuals with MCV < 80 fL, MCH < 27 pg, and hemoglobin < or = 15.3 g/dL in men or < or = 14 g/dL in women, were candidates for molecular thalassemia investigations. Patients with abnormal hemoglobin varieties in hemoglobin electrophoresis were referred to a genetics laboratory for hemoglobinopathy detection.
  
  
  RESULTS
  141 subjects out of 5760 were affected by alpha and beta-thalassemia or a beta-hemoglobinopathy simultaneously, including: 13 (11.1%) fetuses, 55 (38.2%) male cases, and 73 (50.7%) females. Among these 141 alpha-thalassemia patients, 92 cases (65.24%) were beta-thalassemia carriers and 3 (2.12%) were beta-thalassemia major, 43(30.49%) had beta-hemoglobinopathies, and 3 cases (2.12%) had co-inherited beta-thalassemia and variant hemoglobins. 31 beta-gene mutations were observed in this population, the most common being HbS Cd6 (A > T) (24%). These thalassemia determinants account for about 46% of all detected mutations. As for alpha-gene mutations, -3.7 detection was the most prevalent.
  
  
  CONCLUSIONS
  The relatively high prevalence of co-inherited alpha-thalassemia and hemoglobinopathies among beta-thalassemia carriers indicates the importance of molecular analysis to diagnose these double heterozygous or sole homozygous cases for prenatal diagnostic purposes and putting forth strategies to prevent more complicated and dangerous combinations.
authors.forename: Shaban
authors.initials: S
authors.lastname: Alizadeh
authors.forename: Mahsa Shanaki
authors.initials: MS
authors.lastname: Bavarsad
authors.forename: Akbar
authors.initials: A
authors.lastname: Dorgalaleh
authors.forename: Zahra Kashani
authors.initials: ZK
authors.lastname: Khatib
authors.forename: Hossein
authors.initials: H
authors.lastname: Dargahi
authors.forename: Nhaid
authors.initials: N
authors.lastname: Nassiri
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Hamid
authors.forename: Fakher
authors.initials: F
authors.lastname: Rahim
authors.forename: Kaveh
authors.initials: K
authors.lastname: Jaseb
authors.forename: Najmaldin
authors.initials: N
authors.lastname: Saki
mesh_terms: D005260:Female; D006579:Heterozygote; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D009154:Mutation; D015995:Prevalence; D017422:Sequence Analysis, DNA; D017085:alpha-Thalassemia / Q000097:blood / Q000453:epidemiology* / Q000235:genetics; D017086:beta-Thalassemia / Q000097:blood / Q000453:epidemiology* / Q000235:genetics