Sickle cell disease in a carrier with pyruvate kinase deficiency.

We report a case of sickle cell disease (SCD) in a patient who is a carrier for the sickle mutation with no additional mutations in the beta globin genes. Sequencing of the PK-LR genes showed that she was also heterozygous for the L272V mutation in exon 7, which is known to cause pyruvate kinase (PK) deficiency. It appeared that sickling in the heterozygous state is related to decreased oxygen affinity associated with PK deficiency in this unusual case.