Inherited erythrocyte pyruvate kinase deficiency: Studies on 15 members of two related families.

The case of a haemolytic non-spherocytic anaemia with pyruvate kinase (PK) deficiency is reported. The investigation concerns two families with a low level of PK. In the propositus and in the members of his family we have also examined the behaviour of some enzymes and the concentration of red cell metabolites. We confirm the heterogeneity of the manifestation and agree that anaemias due to PK deficiency are complex forms in which the enzyme defect is only one of the symptoms.