Nonspherocytic hemolytic anemia due to hexokinase deficiency

Other Names: Hexokinase deficiency hemolytic anemia

Nonspherocytic hemolytic anemia due to hexokinase deficiency (NSHA due to HK1 deficiency) is a very rare condition mainly characterized by severe, chronic hemolysis, beginning in infancy.

Epidemiology

Approximately 20 cases of this condition have been described to date.

Cause

Nonspherocytic hemolytic anemia due to hexokinase deficiency has been shown to be caused by mutations in the HK1 gene, which cause at least a partial deficiency of the enzyme hexokinase. This enzyme plays an important role in the chemical processes involved in the breakdown of sugar molecules (glycolysis). Red blood cells depend on this process for energy; if an enzyme is defective in any one of the stages, the red blood cell cannot function properly and hemolysis takes place. When red blood cells cannot be replaced faster than they destroy themselves, anemia results.

Inheritance

File:Autorecessive.svg

Autosomal recessive inheritance, a 25% chance

Nonspherocytic hemolytic anemia due to hexokinase deficiency is inherited in an autosomal recessive manner. This means that a mutation in both copies of the gene associated with the condition must be present in order to be affected. The parents of an individual with an autosomal recessive condition each have one mutated copy of the gene in each cell and are referred to as carriers. Carriers typically do not have any signs or symptoms of the condition. When two carriers of the same autosomal recessive condition have children, each child has a 25% (1 in 4) risk to be affected, a 50% (1 in 2) risk to be an unaffected carrier like each parent, and a 25% risk to be unaffected and have 2 normal copies of the gene.

Symptoms

Hexokinase deficiency manifests itself primarily as nonspherocytic hemolytic anemia (NSHA).The signs and symptoms of hexokinase deficiency are very similar to those of pyruvate kinase deficiency, a more common inherited cause of hemolytic anemia, and may include jaundice, fatigue, lethargy, and pale skin. However, the anemia associated with hexokinase deficiency is generally more severe.

There have been reports of some affected individuals having various other abnormalities including multiple malformations, panmyelopathy, and latent diabetes.

Treatment

When severe anemia is present, blood transfusions may be necessary. Affected individuals should avoid any drugs that can cause destruction of red blood cells, as well as any environmental triggers that may be identified.

NIH genetic and rare disease info

• NIH info on Nonspherocytic hemolytic anemia due to hexokinase deficiency

Nonspherocytic hemolytic anemia due to hexokinase deficiency is a rare disease.