Beta-thalassaemia of clinical significance in adult Jamaican Negroes

Thalassemia diagnosed through facial distortion

Thalassemia is an inherited genetic disorder of hemoglobin synthesis characterized by a reduction of either alpha or beta chains of globin. Typical features of patients with thalassemia are skeletal modifications, particularly in the skull and in the malar bone. This report describes a patient who was originally found to have an oro-facial deformity and subsequently demonstrated clinical and laboratory findings consistent with those recorded for thalassemia intermedia.

The laboratory evaluation of microcytic red blood cells

Microcytic red blood cell states are common clinical problems in both adult and pediatric age groups. The recent widespread availability of electronic blood cell counters for performing routine blood counts has increased the detection of microcytic red blood cells. Physicians must workup both symptomatic and asymptomatic patients with microcytic red blood cells before they can initiate proper therapy and/or counseling. The purpose of this review is threefold: (1) to discuss the causes of microcytic red blood cells in terms of disorders of decreased heme production vs. disorders of decreased globin production, (2) to review the clinical laboratory tests useful in differentiating microcytic red blood cell states, and (3) to present a practical approach for the laboratory workup of microcytic red blood cells.

Spinal cord compression in thalassaemia

Two cases of spinal cord compression resulting from extramedullary haemopoiesis in patients with thalassaemia of intermediate clinical severity are reported. The association between mild thalassaemia with long survival and the risk of spinal cord compression from extramedullary haemopoietic deposits is emphasised.

Comparison of haematological features of the beta0 and beta+ thalassaemia traits in Jamaican Negroes

Haematological characteristics have been compared in 29 subjects with heterozygous beta0 thalassaemia and in 33 subjects with heterozygous beta+ thalassaemia, identified by the type of sickle cell-beta thalassaemia among close relatives, in a Jamaican Negro population. Total haemoglobin, MCV and MCH were significantly lower in the beta0 type but the level of Hb A2 was not significantly different. Individual values for MCV, MCH and Hb A2 in the beta+ type occasionally overlapped those in the normal population casting doubt on the adequacy of these criteria in identifying all cases of heterozygous beta+ thalassaemia. The haematological differences are those which would be expected on theoretical grounds. The inability to confidently differentiate the two types of heterozygous beta thalassaemia has implications for genetic counselling. The inability to distinguish heterozygous beta+ thalassaemia from normals on any single haematological index suggests that surveys depending on estimations of Hb A2 or on MCV alone may have underestimated the prevalence of the beta+ thalassaemia gene.