Hassan M. Bahakim

Blood Proteins C and S in Sickle Cell Disease

Proteins C and S are vitamin K-dependent proteins with an essential anti-coagulant function. Protein C exists in an inactive form and is activated by a thrombin-thrombomodulin complex. Protein S combines with protein C and forms a stoichiometric complex which regulates coagulation in the presence of calcium. As patients with sickle cell disease (SCD) bear a high risk of developing thrombo-embolic disorders, we studied the coagulation derangement in 100 patients and 40 normal age- and sex-matched controls. The patients were clinically assessed and classified into sickle cell homozygotes (Hb SS), Hb S heterozygotes (Hb AS) and double heterozygotes for Hb S/beta 0-thalassaemia based on haematological parameters, red cell indices, Hb A2 and F levels and genetic studies. The proteins C and S were estimated and related to the type of the gene defect. The results showed significantly reduced levels of proteins C and S in SCD patients with the highest prevalence of deficiency in patients with a severe disease and frequent episodes of crisis. However, no significant differences were encountered in the level of proteins C and S in the same patients during the steady state and during episodes of crisis. It was concluded that the lower protein C and S levels in SCD is either due to decreased production or increased consumption though this reduction does not seem to play a role in producing thrombo-embolic disorders.

Endocrine functions in sickle cell anaemia patients.

In this study, 80 male and female sickle cell patients, aged 4-50 years, with mild (severity index, SI < 6) and severe (SI > or = 6) forms of the disease were investigated). The levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, cortisol, growth hormone (GH), free thyroxine (T4), and free triiodothyronine (T3) were determined. The results were evaluated and the mean +/- 2 SD values were compared with those obtained in age- and sex-matched normal controls. The findings indicated gonadal hypofunction in the sickle cell patients, but with varied deviations from the mean results. Patients with the severe form of the sickle cell disease showed more frequent abnormalities of LH, FSH, cortisol and testosterone in comparison with the patients with a mild disease. The LH, FSH, cortisol and testosterone levels were lower, while T3 and T4 did not show significant differences between patients and the controls. The results suggest that the sickle cell gene abnormality has an adverse effect on endocrine functions. Follow-up and appropriate management of endocrine dysfunctions are advocated in such patients.

Sickle Cell Gene in the Population of Saudi Arabia

A comprehensive screening program was initiated in Saudi Arabia in 1982 to determine the frequency of the sickle cell (Hb S) gene in the different regions of Saudi Arabia. Over a period of 10 years 30,055 samples were collected from 36 areas in the five provinces of Saudi Arabia; these were screened using electrophoretic techniques in alkaline and acid pH for the presence of Hb S in heterozygous and homozygous states. The overall prevalence of Hb AS was 7.36% and Hb SS was 1.06%, giving an Hb S gene frequency of 0.047. The results from the different regions were separated and the prevalence of Hb AS and Hb SS and Hb S gene frequencies were calculated in each province and each region. The prevalence of Hb AS and Hb SS cases ranged from O to 25.88% and O to 5.27%, respectively. No case of Hb AS or Hb SS were identified in certain areas of the central province (Al-Russ, Al-Unaiza, Al-Mesnab and Bkaria) and northern province (Qurayat and Al-Jouf). In the southern province both Hb S homozygotes and heterozygotes were encountered in all regions except Farasan Island. In all other regions the Hb S gene was encountered, but at a variable frequency. Applying Hardy-Weinberg equilibrium it was observed that in the majority of the regions the observed Hb S homozygotes were significantly higher compared to the number expected (p < 0.0001). This was believed to be due to bias as the samples were collected in the hospital. The Hb S gene frequency in the different regions ranged from 0 to 0.17 when the frequency was calculated on the basis of both Hb AS and Hb. SS cases, and 0 to 0.13 if the gene frequency was calculated after eliminating the Hb SS cases. A close correlation was observed between the Hb S gene frequency and malaria endemicity. This study shows that the Hb S gene occurs frequently in several regions of Saudi Arabia and there is an urgent need to implement control and prevention programs to reduce the number of Hb S homozygous cases.

Is HLA‐DRW 13 (W6) Associated with Juvenile Myoclonic Epilepsy in Arab Patients?

Summary: In a study of 32 unrelated Arab patients with juvenile myoclonic epilepsy (JME), we compared the frequencies of human leukocyte antigen (HLA) class I and II alleles with those of unrelated healthy controls. A significant difference between the phenotypic frequencies in JME patients and controls was observed for DRW13, the split of DRW6 (37.5 vs 11% of controls). The strength of association as measured by the relative risk was 4.85 for this antigen (p = 0.002). The possible association of JME with HLA‐DRW6 recently reported in Caucasians was confirmed in this study. This finding speaks for the homogeneity of the disease among Arabic and Caucasian JME patients. The existence of this association is evidence of a locus in the HLA region that influences expression of JME.

Hereditary bleeding disorders in Riyadh, Saudi Arabia.

The result of an eight-year retrospective analysis of patients with hereditary bleeding disorders (HBD) at King Khalid University Hospital, Riyadh, is presented. One hundred and sixty-eight patients referred for investigation for suspected bleeding disorders had bleeding symptoms which fulfilled the criteria for HBD and were categorized as follows: 1) coagulation factor deficiencies: 41 patients had hemophilia A, while 16 had hemophila B; two patients each had factors XI and XII deficiency; four patients each had factors V and VIII deficiency and one patient had factor VII deficiency. There were two patients with dysfibrinogenemias and one with afibrinogenemia. 2) Von Willerbrands disease was the second most common cause of HBD-25 patients were encountered in 15 different families. 3) Qualitative platelet disorders consisted of Glanzmanns thrombasthenia, with 18 patients, Bernard-Soulier disease, with five patients, and other qualitative platelet disorders, with 33 patients. 4) In 14 patients who presented with a history of bleeding, the only abnormality noted was prolongation of the bleeding time and normal coagulation and platelet function, and no definitive diagnoses could be established. The distribution of hereditary bleeding disorders obtained in this study resembles what has already been established in Western countries, with the exception of an increase of platelet disorders, mostly due to the increased rate of consanguinity in the community.

Coagulation Changes in Sickle Cell Disease in Early Childhood

Measurements of the coagulation system were carried out in children with sickle cell disease (SCD) in both steady state and on the 1st day of painful crisis and were compared to age- and sex-matched healthy controls. No significant differences were found in prothrombin time, partial thromboplastin time, thrombin time, reptilase time, plasma fibrinogen, antithrombin III, factor VIII:C, ristocetin-cofactor (Ri-Cof) and platelet aggregation responses to ADP, collagen and adrenaline. Abnormal aggregation responses to ristocetin were noted in all patients with SCD when compared to controls. Daily measurements during the first 4 days of painful crisis showed significant elevation of fibrinogen and Ri-Cof and enhancement of aggregation to ADP and adrenaline by the 3rd day of crisis. It was concluded that the changes noted, rather than being primarily responsible for the onset of crisis, can only be secondary changes arising from the aetiological factors of crisis, i.e. stasis and acute-phase proteins.

Muslim parents' perception of and attitude towards cancer.

This paper examines the perception of and attitudes to cancer of 55 Muslim Arab parents and 5 close relatives of children with malignant disease. These subjects were interviewed in the Arabic language and more than 90% of them were Saudi. The results showed that despite the fact that 87% were either illiterate or did not attend secondary schools, 60% gave a reasonable description of cancer and 60% considered it important to know more about the symptoms of the childs malignant disease. The results also showed that the majority of the subjects considered that the prognosis lay in the hands of Allah (God) and that the fate of the child was beyond the control of the treating physician. Based upon these results and personal experience, recommendations have been put forward for oncologists who would deal with Muslim parents of the children with malignant disease.

Prevalence of iron deficiency in Saudi children from birth to 15 months of age.

A cross-sectional study was carried out to determine the prevalence of iron deficiency among healthy Saudi children from birth to 15 months of age. The groups studied were: newborns, 3-4 months, 5-6 months, 7-8 months, 9-10 months and 12-15 months of age. The age groups were dictated by the vaccination schedule. Serum ferritin was measured and transferrin saturation calculated in each subject. The lower limits of normal were taken as a transferrin saturation of less than 10% and a serum ferritin of less than 12 micrograms/l. A total of 333 serum samples was adequate for analysis. None of the newborns or the 3-4-month-old infants had evidence of iron deficiency. At 5-6 months only 3.3% of subjects had iron deficiency. In the subsequent older age groups the prevalence of iron deficiency increased significantly with age from 9.3% to 12.7% and reached 14.5% in the oldest age group. Screening for iron deficiency in children attending well-baby clinics and hospitals at ages of 12-15 months is recommended.

Hepatitis B and A markers in children with thalassaemia and sickle-cell disease in Riyadh.

SUMMARYSera from 40 children with β-thalassaemia major, 54 children with sickle-cell disease and 120 matched controls were examined by radio-immunoassay for hepatitis B and A markers. The overall prevalence of hepatitis B virus markers was highest in children with thalassaemia followed by children with sickle-cell disease and lowest in the control group. The hepatitis A marker showed a reversed pattern, being lowest in the thalassaemic group. The high incidence of hepatitis B infection was presumably due to frequent blood transfusions, frequent exposure to hospital environment and the high carrier rate in the community. Frequent blood transfusions, however, seem to protect against hepatitis A virus infection.Sera from 40 children with beta-thalassaemia major, 54 children with sickle-cell disease and 120 matched controls were examined by radio-immunoassay for hepatitis B and A markers. The overall prevalence of hepatitis B virus markers was highest in children with thalassaemia followed by children with sickle-cell disease and lowest in the control group. The hepatitis A marker showed a reversed pattern, being lowest in the thalassaemic group. The high incidence of hepatitis B infection was presumably due to frequent blood transfusions, frequent exposure to hospital environment and the high carrier rate in the community. Frequent blood transfusions, however, seem to protect against hepatitis A virus infection.

Does Gγ/Aγ ratio and Hb F level influence the severity of sickle cell anaemia

Sickle cell anaemia (SCA) exhibits significant variations in clinical presentation in different populations for which several genetic factors including SCA-associated α-and β-thalassaemias, G-6-PD deficiency and elevated Hb F level have been implicated as possible ameliorating factors. Saudi Arabia is unique in that mild and severe forms of the disease occur at a high frequency. We investigated the Gγ/Aγ ratio and Hb F level and correlated these values with the severity of SCA. The results showed that Hb F level varies significantly in both groups of patients with no evident correlation with the mild clinical manifestations. However, Gγ/Aγ ratio correlated significantly with the disease severity where a high ratio was observed in patients with the mild and a low ratio in patients with the severe disease. The results are evaluated and discussed in the light of correlation studies and regression analysis.