title: The co-inheritance of alpha-thalassemia and sickle cell anemia is associated with better hematological indices and lower consultations rate in Cameroonian patients and could improve their survival.
abstract: BACKGROUND
  Co-inheritance of α-thalassemia was reported to be associated with a delayed age of disease onset among Cameroonian Sickle Cell Anemia (SCA) patients. The present study aimed to explore the correlation between α-thalassemia, hematological indices, and clinical events in these patients.
  
  
  RESULTS
  We studied 161 Cameroonian SCA patients and 103 controls (59.1% HbAA) with median ages of 17.5 and 23 years. RFLP-PCR was used to confirm SCA genotype and to describe haplotypes in the HBB-like genes cluster. Multiplex Gap-PCR was performed to investigate the 3.7 kb α-globin gene deletions. SNaPshot PCR, capillary electrophoresis and cycle sequencing were used for the genotyping of 10 SNPs in BCL11A, HMIP1/2, OR51B5/6 and HBG loci, known to influence HbF levels. Generalised linear regression models adjusted for age, sex and SNPs genotypes was used to investigate effects of α-thalassemia on clinical and hematological indices. The median rate of vaso-occlusive painful crisis and hospitalisations was two and one per year, respectively. Stroke was reported in eight cases (7.4%). Benin haplotype was the most prevalent (66.3%; n = 208 chromosomes). Among patients, 37.3% (n = 60) had at least one 3.7 kb deletion, compared to 10.9% (n = 6) among HbAA controls (p<0.001). Among patients, the median RBC count increased with the number of 3.7 kb deletions [2.6, 3.0 and 3.4 million/dl, with no, one and two deletions (p = 0.01)]. The median MCV decreased with the number of 3.7 kb deletion [86, 80, and 68fl, with no, one and two deletions (p<0.0001)], as well as median WBC counts [13.2, 10.5 and 9.8×109/L (p<0.0001. The co-inheritance of α-thalassemia was associated with lower consultations rate (p = 0.038).
  
  
  CONCLUSIONS
  The co-inheritance of α-thalassemia and SCA is associated with improved hematological indices, and lower consultations rate in this group of patients. This could possibly improve their survival and explain the higher proportion of α-thalassemia among patients than controls.
authors: Division of Human Genetics, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town (UCT), Cape Town, Republic of South Africa.
authors: Maryam Bibi
authors: MB
authors: Rumaney
authors: Department of Microbiology, Parasitology and Haematology, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon.
authors: Valentina Josiane
authors: VJ
authors: Ngo Bitoungui
authors: Division of Human Genetics, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town (UCT), Cape Town, Republic of South Africa.
authors: Anna Alvera
authors: AA
authors: Vorster
authors: Division of Human Genetics, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town (UCT), Cape Town, Republic of South Africa; MRC Human Genetics Research Unit), Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town (UCT), Cape Town, Republic of South Africa.
authors: Raj
authors: R
authors: Ramesar
authors: Non-Communicable Diseases Research Unit, South African Medical Research Council and University of Cape Town, Cape Town, South Africa.
authors: Andre Pascal
authors: AP
authors: Kengne
authors: Department of Microbiology, Parasitology and Haematology, Faculty of Medicine and Biomedical Sciences, University of Yaoundé 1, Yaoundé, Cameroon.
authors: Jeanne
authors: J
authors: Ngogang
authors: Division of Human Genetics, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town (UCT), Cape Town, Republic of South Africa.
authors: Ambroise
authors: A
authors: Wonkam
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000755:Anemia, Sickle Cell / Q000097:blood / Q000150:complications / Q000235:genetics* / Q000401:mortality; D001772:Blood Cell Count; D002163:Cameroon; D005260:Female; D017353:Gene Deletion; D006239:Haplotypes; D006441:Hemoglobin A / Q000235:genetics*; D006451:Hemoglobin, Sickle / Q000235:genetics*; D006801:Humans; D040582:Inheritance Patterns; D008297:Male; D005810:Multigene Family; D020641:Polymorphism, Single Nucleotide; D012017:Referral and Consultation / Q000706:statistics & numerical data; D016019:Survival Analysis; D055542:alpha-Globins / Q000235:genetics*; D017085:alpha-Thalassemia / Q000097:blood / Q000150:complications / Q000235:genetics* / Q000401:mortality; D055544:beta-Globins / Q000235:genetics
chemical_list: D006451:Hemoglobin, Sickle; D055542:alpha-Globins; D055544:beta-Globins; C028672:hemoglobin AA; D006441:Hemoglobin A