Sickle-Cell Disease in Brazzaville, Congo: Genetical, Hematological, Biochemical and Clinical Aspects

Abstract

Clinical, hematological and molecular features of 116 unrelated sickle-cell anemia patients from Brazzaville were investigated. The mean age of the patients was 9.4 ± 5.3 years. 232 β^s-chromosomes were haplotyped and almost all sickle cell anemia patients (91%) were homozygous for the Bantu haplotype. All hematological indices were similar for males and females. Mean hemoglobin (Hb) concentration was 6.6 ± 1.4 g/dl. Fetal Hb (HbF) levels were from 1 to 28%, with a mean of 8.8 ± 5.8%. There was a curvilinear relationship between %HbF and age suggesting that HbF level had a selective effect on the survival of patients. This effect was sex dependent. The (–α^3.7) gene frequency was 0.45 and was not affected by stratification for age. Hematological characteristics of patients with (–α/αα, –α/–α) and without (αα/αα) the –α^3.7 α-thal-2 deletion showed trends similar to those reported in Jamaican and US sickle cell anemia patients. Hyperbilirubinemia (>38 μmol/l) was common and high lactic dehydrogenase (LDH) concentrations were recorded. Bilirubin concentrations for males and females were similar whereas those for LDH concentration were not. Hepatomegaly and splenomegaly were common. Splenomegaly was strongly associated with the –α^3.7 α-thal-2 deletion. These clinical and hematological observations indicate a more severe form of hemolytic disease in Congolese SS patients.

An observational study of children with sickle cell disease in Kilifi, Kenya

“…Higher values of 80–90 g/l have been reported from studies conducted in Jamaica and the USA (Serjeant et al , 1981; Thomas & Serjeant, 1997; Miller et al , 2000; Quinn & Ahmad, 2005), an observation that may be explained by the higher prevalence of iron deficiency found in Kilifi (Nyakeriga et al , 2005). Our observation that MCV was significantly raised in children with SCD is consistent with previous studies (Serjeant et al , 1981; Diop et al , 1999; Mouele et al , 1999), presumably due to the presence of a significant number of reticulocytes in the peripheral circulation. The mean MCHC (mean cell haemoglobin concentration) of 318 g/l is consistent with other reports from Africa but slightly lower than reported in Jamaica (Diop et al , 1999; Mouele et al , 1999).…”

“…Our observation that MCV was significantly raised in children with SCD is consistent with previous studies (Serjeant et al , 1981; Diop et al , 1999; Mouele et al , 1999), presumably due to the presence of a significant number of reticulocytes in the peripheral circulation. The mean MCHC (mean cell haemoglobin concentration) of 318 g/l is consistent with other reports from Africa but slightly lower than reported in Jamaica (Diop et al , 1999; Mouele et al , 1999). It is also significantly lower than that of normal children from the local population.…”

“…Subsequent episodes of recurrent vaso-occlusion and infarction lead to gradual auto-splenectomy, and in most patients the spleen is no longer palpable by the age of 10 years. In our cohort splenomegaly persisted until late childhood such that the spleen was still palpable in more than one-third of 10-year olds, an observation that is in accordance with previous studies conducted in sub-Saharan Africa (Esan, 1966; Adekile et al , 1988, 1993; Thuilliez & Vierin, 1997; Mouele et al , 1999). Some reports have attributed the persistence of splenomegaly in African children with SCD to the effects of malaria, although in this study we did not find an association with either the number of episodes of malaria or level of parasitaemia.…”

“…We are not aware of any previous reports of AST levels in steady-state African patients with SCD. One study found that lactate dehydrogenase levels were almost threefold higher than normal in adults and children living with SCD in the Congo (Mouele et al , 1999), although whether this was due to haemolysis or hepatic dysfunction is unclear. As expected, renal function tests were normal in all patients and the majority had a normal urine dipstick, although proteinuria and haematuria were detected in some older children.…”

Molecular characterization of sickle cell anemia in the Northern Brazilian state of Pará

“… (1) Cardoso and Guerreiro (2006); (2) Pante‐de‐Souza et al (1998); (3) Adorno et al (2008); (4) Lyra et al (2005); (5) Figueiredo et al (1994); (6) Gonçalves et al (2003); (7) Bezerra et al (2007); (8) Zago et al (1992); (9) Gonçalves et al (1994); (10) Figueiredo et al (1996); (11) Wagner et al (1996); (12) Mouélé et al (1999); (13) Öner et al (1992); (14) Kulozik et al (1986); (15) Pagnier et al (1984). …”