Studies on sickle cell heterozygotes in Saudi Arabia--interaction with alpha-thalassaemia

Acta Haematol. 1986;75(2):100-4. doi: 10.1159/000206095.


This study was conducted in the Eastern Province of Saudi Arabia where both thalassaemia and Hb S genes occur at a high frequency. In 171 Saudi Hb S heterozygotes, the range for Hb S was found to be 17-45% with a mean of 31.0%. Frequency distribution histograms showed a trimodal distribution. Peak A, B and C had 18-28, 28-35 and 35-45% Hb S values, respectively. Determination of alpha/beta ratio showed that these findings result from interaction of Hb S with the alpha-thalassaemia gene. Peak C with mean for Hb S of 40% consisted of a majority of individuals with no thalassaemia gene, and the alpha/beta ratio was 0.98% +/- 0.06. Peak B individuals were heterozygous for alpha-thalassaemia 2 with an alpha/beta ratio of 0.80% +/- 0.06 and peak A individuals were homozygous to alpha-thalassaemia 2 with an alpha/beta ratio of 0.58 +/- 0.08. The presence of alpha-thalassaemia 2 in homozygotes results in hypochromia and microcytosis, with little effect on haematological parameters.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anemia, Sickle Cell / genetics*
  • Erythrocyte Indices
  • Hemoglobin, Sickle / genetics*
  • Heterozygote
  • Humans
  • Saudi Arabia
  • Sickle Cell Trait / complications
  • Sickle Cell Trait / genetics*
  • Thalassemia / complications
  • Thalassemia / genetics*


  • Hemoglobin, Sickle