DNA haplotype distribution in Algerian ? thalassaemia patients

Abstract

An evaluation of beta thalassaemia mutations and the associated chromosomal haplotypes has been made among Algerian thalassaemic patients in this extended series. The major features of our findings are: (i) due to elevated proportion of consanguinity, the frequency of true homozygotes for a defect is high; (ii) Despite this high homozygosity within families, the number of molecular defects resulting in beta thalassaemia are very heterogeneous within this population. This is exemplified not only by the high heterogeneity of haplotypes and associated mutations, but also by the definition of several new haplotypes, among which two of them were found to be associated with novel mutations. Family studies have been performed in parallel to evaluate the degree of feasibility of antenatal diagnosis in this population.

Spectrum of β thalassemia mutations and HbF levels in the heterozygous Moroccan population

“…The most abundant mutations are ␤ 0 39 (15.5%) and ␤ 0 fsCD8(−AA) (15.5%) ( Table II). The latter opposes the rarity of ␤ + IVS1,nt110 (2%), in association with haplotype I, as in Algeria [30], Tunisia [31], and Portugal [18,32], supporting the idea of a recent introduction in the Moroccan genetic background. The third most frequent mutation is ␤ + IVS1,nt6 (T→C) (14%) in haplotypes VI and VII as described in Portugal [18,32,33], whereas in Algeria, Tunisia, and Egypt it is associated with haplotype VI [34,35].…”

Re-evaluation of the .BETA.-globin gene cluster haplotypes in Japanese, Koreans, and three Colombian Amerinds (Wayuu, Kamsa, and Inga tribes)

“…All Japanese and Koreans who possessed subhaplotype 1 were heterozygous for subhaplotypes 1 and 2. This subhaplotype 1 (-----) has been reported already in Argentine Amerinds (Kaufman et al, 1998), Mexican mestizos (Villalobos-Arambula et al, 1986), Lowland (Chen et al, 1990) and Highland Melanesians (Hill et al, 1988), Polynesians (Wainscoat et al, 1986), Algerians (Rouabhi et al, 1988), and Asian Indians (Varawalla et al, 1992). It has also recently been described in Inga Amerind of Colombia (Mesa et al, 2000).…”

Unexpected discovery of hemoglobinopathy C/β° thalassemia

“…The objective mutations in C/β‐thalassemia double heterozygotes are Cd 39 C → T and IVSI‐110 G → A 16. Cd6 (‐A) also known as FSC 6 reaches its highest frequency in Algeria with 17.7% followed by Morocco with 10% of β‐thalassemic chromosomes study 21, 22. It is associated with two haplotypes III and IX,4 which are also common in Morocco and Algeria.…”