Congenital dyserythropoietic anaemia, types I and II: aberrant pattern of erythrocyte membrane proteins in CDA II, as revealed by two-dimensional polyacrylamide gel electrophoresis

Congenital dyserythropoietic anaemia type II (HEMPAS): a family study

A family having two affected siblings with congenital dyserythropoietic anaemia type II (HEMPAS) is described. The proband was diagnosed after referral for investigation of haemolytic anaemia. Clinical evaluation and in vivo red cell (RBC) survival and the sequestration studies in the proband indicated that the anaemia was due to a combination of ineffective erythropoiesis and premature destruction of RBCs in the spleen. Scanning electron microscopic examination of peripheral RBCs was undertaken and is reported. The polypeptide composition of RBC membranes was also examined using polyacrylamide gel electrophoresis after solubilisation in sodium dodecyl sulphate. These results are also reported.

Studies of ineffective erythropoiesis and peripheral haemolysis in congenital dyserythropoietic anaemia type II

Erythrokinetic parameters were estimated in six patients suffering from congenital dyserythropoietic anaemia type II (CDA II) by means of a mathematical model of iron kinetics. A wide variation in effectiveness of erythroid activity was observed, and a significant negative correlation was found between ineffective erythropoiesis and peripheral haemolysis. In four patients with prominent peripheral haemolysis, splenectomy was carried out. Marked improvement in their clinical condition and in haemoglobin level resulted.

Morphological Abnormalities in cultured erythroid colonies (BFU-E) from the blood of two patients with HEMPAS

The results of cytological and ultrastructural analysis of erythroid burst colonies derived from the peripheral blood of two patients with HEMPAS have been compared to those obtained in normal controls. Using the plasma clot technique, in studies on 10 subjects we confirmed that most of the colonies consisted or erythroblasts with a synchronous and normal maturation involving a wave of nuclear extrusion at day 13. In contrast, the majority of well-haemoglobinized colonies from HEMPAS consisted of numerous bi- or multinucleated erythroblasts displaying the supplementary double membrane beneath their plasma membrane. This excessive membrane may be present as a continuous or fragmented structure in different erythroblasts from the same colony. These findings suggest that the progeny derived from one BFU-E may vary considerably in their morphological defects. Furthermore, one third of the packed colonies appeared to be formed by non-haemoglobinized cells which were clearly identified by electron microscopy as very early erythroblasts. These cells were unable to mature and subsequently lysed. Thus dyserythropoiesis occurred in culture both at early and late stages of maturation. These studies clearly demonstrate that HEMPAS is a disorder resulting from defective erythroid committed cells.

Type I congenital dyserythropoietic anaemia with myelopoietic abnormalities and hand malformations

Type I dyserythropoietic anaemia was diagnosed in an infant, who presented with respiratory distress and hepatosplenomegaly soon after birth. Anaemia became manifest during the neonatal period. The case clearly proves the congenital nature of the disease. Abnormalities of the myelopoietic series indicate that it might be a stem cell disease and the presence of skeletal anomalies of the hands suggests a genetic relationship to some cases of Fanconi and Diamond anaemia. No serum lipid or vitamin E deficiency was present as in type II congenital dyserythropoietic anaemia. Serial serum ferritin determinations indicated that iron stores are increased early in type I congenital dyserythropoietic anaemia despite no transfusion load.