Spectrum of beta-thalassaemia mutations in the population of Saudi Arabia.

A study of beta-thalassaemia alleles in 29 beta-thalassaemia homozygotes and HbS/beta-thalassaemia patients from western Saudi Arabia using the allele-specific priming technique of the polymerase chain reaction revealed a total of five mutations. The spectrum of mutations found in the western region is significantly different to that previously reported in the eastern region, and brings the total number of mutations observed in Saudi Arabian nationals to ten. A comparison of the types and frequencies of the Saudi Arabian mutations with those found in neighboring Arab countries is made.

Prevalence of thalassaemias in ethnic Saudi Arabians.

A study of the prevalence of alpha- and beta-thalassaemia and the sickle cell gene was carried out on 840 healthy adult male Saudi Arabians of different tribal origins. Complete blood count, haemoglobin electrophoresis and HbA2 estimation were carried out on all. Globin biosynthetic analysis was carried out on all 85 subjects with microcytic red cells and on 180 randomly selected subjects with normal red cell indices. The results showed prevalence of beta-thalassaemia of 3.0%, alpha/beta thalassaemia of 0.9%, alpha-thalassaemia of 43.3% and sickle trait of 5.7%. There were tribal variations in the prevalence of both alpha-thalassaemia and the sickle gene.

Non-benign sickle cell anaemia in western Saudi Arabia.

Seventy-one Saudi and Yemeni Arabs with sickle cell anaemia from western Saudi Arabia aged between 1 1/2 and 42 years were studied. The mean steady state haemoglobin concentration of 8.1 g/dl was lower than that of 10.7 g/dl reported previously for sickle cell anaemia in eastern Saudi Arabia. The patients were divided into an SSLF group with fetal haemoglobin (HbF) of 10.0% or below (44 patients) and an SSHF group having HbF above 10.0% (27 patients). No significant differences were found in the haemoglobin concentrations, haematological indices and incidences of bone changes of the two groups. SSLF patients were significantly more prone to infections (P less than 0.01), however. Also, there was an overall high incidence of hepatomegaly (69.0%) and splenomegaly (54.9%) and hepatomegaly was significantly more common in the SSLF group (P less than 0.02). Many of the patients, even with HbF levels over 10.0%, did not follow a benign course and suffered from severe anaemia, infections of the respiratory and urinary tracts, bone pains and infarcts, or bossing of the skull. Rarer complications included hepatic crisis, chest syndrome, retinal haemorrhage, epistaxis and hemiplegia. It is therefore apparent that Saudi Arabian sickle cell anaemia, even in patients with raised haemoglobin F levels, may be as clinically severe as in African patients.

Lymphocyte response to blood transfusion in man: a comparison of different preparations of blood.

The appearance of atypical lymphocytes in post-transfusion blood, their incorporation of tritiated thymidine in tissue culture and the elimination of cytotoxic antibody production, have been used as markers to show that frozen red cells are the least immunogenic when compared with dextran sedimented blood and whole blood donations. The absence of atypical lymphocytes and failure to produce lymphocytotoxic antibodies after transfusion of frozen cells is highly significant (P is less than 0.001) when compared with whole blood donations.

Platelet counts during normal pregnancy.

Eleven reports of platelet counts were found in the literature which reported a progressive increase, no change, or a progressive fall during pregnancy. The counts had been made using venous or capillary blood, with either simple dilution or red cell lysis prior to enumeration in a haemocytometer, with or without phase-contrast microscopy. It was therefore decided to examine whole blood platelet counts taken during normal pregnancy. Results from 405 venous blood samples, using an electronic platelet counter, confirmed the finding of a significant progressive fall in platelet counts during normal pregnancy, the lowest counts falling in some women outside the recognized normal range of values.