The effect of alpha-thalassemia on cord blood red cell indices and interaction with sickle cell gene.

BACKGROUND: AA+/--thalassemia is known to be prevalent in the Eastern region of Saudi Arabia. There are no large scale reports regarding the effect of alpha-thalassemia on red cell indices of cord blood from Saudi Arabia. Similarly, there are no reports regarding the interaction of AA+/--thalassemia and the sickle cell gene in relation to red cell indices in cord blood. To address these issues, we undertook a study on neonatal cord blood samples. MATERIALS AND METHODS: In a prospective study, cord blood samples from 504 neonates from the Qatif area of the Eastern Province of Saudi Arabia were analyzed for complete blood counts (CBC) and cellulose acetate Hb electrophoresis. Hb S was confirmed by citrate agar Hb electrophoresis. RESULTS: There were 243 case samples with normal Hb electrophoresis (Hb A 27.2+/-7% and Hb F 72.6+/-7.7%). Their mean Hb (g/dL), RBC (x10(12) /L), Hct (%), MCV (fl), MCH (pg), MCHC (g/dL), RDW-SD (fl) and RDWCV (%) were 15.05+/-1.6, 4.5+/-0.5, 47.4+/-5.3, 106+/-8, 33.6+/-2.3, 31.8+/-1.7, 69.2+/-9.5 and 17.9+/-1.7, respectively. There were 136 cases with alpha-thalassemia trait (alphaTT), 57 cases with sickle cell trait (SCT) and 50 cases of sickle cell trait with alpha-thalassemia trait (SCT/alphaTT). There were 10 cases of Hb H disease (6 definite), including one with sickle cell disease (SCD) and two with SCT, Hb Bart's 23.9%-43.6%; four probable with Hb Bart's 10.9%-16.1%, and one with SCT. The effect on red cell parameters in Hb H disease were most pronounced. In addition, there were seven cases of SCD, four of whom had coexistent AA+/--thalassemia trait (SCD/alphaTT). CONCLUSION: The prevalence of alpha-thalassemia in this cohort of Saudi population was 39.99%. Hb H disease appeared as common as SCD. Sickle cell gene was seen in 23.4% of neonatal samples. alpha-Thalassemia gene significantly reduces MCH, MCV, RDW-SD, Hct, Hb, and increases RBC count in both normal or sickle cell trait neonates. Generally, the variation of red cell parameters is directly proportional to the amount of Hb Bart's in the cord blood. Sickle cell gene in itself produces low MCV, RDW-SD and MCH in cord blood. Further, normal reference values for red cell parameters of cord blood are established.

Neonatal screening for sickle cell disease, glucose-6-phosphate dehydrogenase deficiency and a-thalassemia in Qatif and Al Hasa.

BACKGROUND: Screening programs to determine the frequency of sickle cell, glucose-6-phosphate dehydrogenase deficiency and alpha-thalassemia gene are available in Saudi Arabia, although not used frequently. Greater use of these programs will decrease the morbidity and mortality of Saudi children affected by these disorders. PATIENTS AND METHODS: Neonatal hemoglobin electrophoresis and glucose-6-dehydrogenase fluorescent spot tests were performed on newborn babies delivered between December 1992 and December 1993 at the Qatif Central Hospital and at the King Fahad Hospital in Al Hasa. Cord blood samples were collected from babies born in these two hospitals. Babies born in other hospitals had blood collected in their first visit to Qatif primary care centers at the time of vaccination. All specimens were sent to Dammam Central Laboratory. The diagnosis of sickle cell and alpha-thalassemia was based on cellulose acetate electrophoresis and confirmed by agar gel electrophoresis, and glucose-6-phosphate dehydrogenase was confirmed by fluorescent spot test. RESULTS: A total of 12,220 infants, including 11,313 Saudis (92.6%), were screened over a 12-month period. The common phenotypes detected in these infants included AF, AF Bartâs, SFA, SFA Bartâs, FS and FS Bartâs. In the Saudi infants, homozygous sickle cell disease was detected in 2.35% and 1.08% in Qatif and Al Hasa, respectively. The frequencies of sickle cell gene were 0.1545% and 0.1109% in Qatif and Al Hasa. alphathalassemia gene based on an elevated level of Hb Bartâs were 28% and 16.3% in Qatif and Al Hasa. The screening for G6PD deficiency revealed a high prevalence of 30.6% and 14.7% in Qatif and Al Hasa. In the non-Saudi infants, the frequencies were low. CONCLUSION: The outcome of this study indicates that the Saudi populations in Qatif and Al Hasa are at risk for hemoglobinopathies and G6PD. Neonatal screening programs are essential and cost effective and should be maintained as a routine practice.

Splenectomy and acute splenic sequestration crises in sickle cell disease.

Acute splenic sequestration crises (ASSC) is one of the complications of sickle cell disease (SCD) that can be life-threatening due to loss of blood volume. Over a 5-year period, we have treated 19 patients ranging in age from 4 to 32 years with ASSC. There were 14 males and 5 females; 17 had homozygous SCD and the other 2 had sickle thalassemia. Two patients presented with severe anemia and acute circulatory collapse; 1 of them developed residual weakness of his limbs and decreased visual acuity. Nine patients underwent splenectomy after major episodes of sequestration while the remaining 10 had recurrent minor episodes of sequestration. The clinical features and the role of splenectomy are discussed.