Molecular basis of haemoglobinopathies and G6PD deficiency in the Comorian population.
BACKGROUND
The Comoro archipelago is characterised by a high prevalence of red cell genetic disorders such as G6PD deficiency and haemoglobinopathies, being a region endemic for malaria. Over the last 15 years, the city of Marseilles in France has become the main destination for Comorian immigrants. This Comorian community includes patients with sickle cell disease, sickle cell/beta-thalassaemia trait, thalassaemias and G6PD deficiency.


METHODS
Allele frequencies for haemoglobin S, beta-thalassaemia and G6PD deficiency were determined from neonatal and prenatal screenings of the Comorian community. Haemoglobin fractions were detected by isoelectrofocalisation, and the quantitation of HbS, HbA, HbA(2) and HbF was performed by cation exchange high performance liquid chromatography. The molecular study involved 31 alleles carrying the betaS mutation (Cd 6 [A-->T]), six beta-thalassaemic alleles and 17 G6PD-deficient alleles, selected from a group of carriers or affected subjects.


RESULTS
Allele frequencies were 3% for haemoglobin S, 1% for beta-thalassaemia trait and 9.5% for G6PD deficiency. Molecular analysis had revealed that the African alleles are predominant, being present in almost all the subjects studied. Mediterranean alleles were found for all the beta-thalassaemia mutations and for three G6PD chromosomes out of 17.


CONCLUSIONS
These data are consistent with the mixed Arab and African origin of the population of the Comoro Islands, and are of clinical interest in prenatal and newborn screening plans.
Badens
C
C
Centre d'Enseignement et de Recherche en Génétique Médicale, Hôpital d'enfants de la Timone, Marseilles, France. badens@medecine.univ-mrs.fr
Martinez di Montemuros
F
F
Thuret
I
I
Michel
G
G
Mattei
J F
JF
Cappellini
M D
MD
Lena-Russo
D
D
D000483:Alleles; D000755:Anemia, Sickle Cell / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics; D018912:Arabs / Q000235:genetics; D044383:Black People / Q000235:genetics; D017507:Comoros / Q000453:epidemiology / Q000208:ethnology; D004252:DNA Mutational Analysis; D005260:Female; D018703:Founder Effect; D005602:France / Q000453:epidemiology; D005787:Gene Frequency; D005820:Genetic Testing; D005914:Globins / Q000235:genetics*; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics*; D005955:Glucosephosphate Dehydrogenase Deficiency / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics; D006453:Hemoglobinopathies / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics*; D006455:Hemoglobins, Abnormal / Q000032:analysis / Q000235:genetics*; D006801:Humans; D007194:India / Q000208:ethnology; D007231:Infant, Newborn; D007492:Iran / Q000208:ethnology; D007567:Jaundice, Neonatal / Q000208:ethnology / Q000235:genetics; D008297:Male; D009073:Mozambique / Q000208:ethnology; D015997:Neonatal Screening; D011296:Prenatal Diagnosis; D015995:Prevalence; D017384:Sequence Deletion; D017086:beta-Thalassemia / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics
D006455:Hemoglobins, Abnormal; D005914:Globins; C030448:hemoglobin Bart's; D005954:Glucosephosphate Dehydrogenase