Rare diseases: Rh deficiency syndrome

Rh deficiency syndrome designates rare individuals who have either absent (Rhnull) or markedly reduced (Rhmod) Rh antigen expression, mild to moderate hemolytic anemia associated with the presence of stomatocytes, and occasional spherocytes on the peripheral blood film. Hemolytic anemia is improved by splenectomy.

Here is one example of a case:

The hematological aspects of the original case of Rhmod are reported. The subject, as in other reported cases, had a chronic hemolytic anemia characterized by stomatocytosis, reduced osmotic fragility, and abnormal autohemolysis correctable with the addition of glucose. The 51Cr red cell survival studies showed the spleen to be the preferential site of red cell destruction and splenectomy produced a dramatic improvement in red cell survival. The topic of Rh deficiency syndrome (Rhnull and Rhmod) is briefly reviewed with regard to the number of cases reported, to genetic aspects, to the hematological findings, and to the results of splenectomy.

A cause for Rh deficiency and Rh-null hemolytic anemia (RHN) is RHAG (Rh-associated glycoprotein).
The protein encoded by this gene is erythrocyte-specific and is thought to be part of a membrane channel that transports ammonium and carbon dioxide across the blood cell membrane. The encoded protein appears to interact with Rh blood group antigens and Rh30 polypeptides. Defects in this gene are a cause of regulator type Rh-null hemolytic anemia (RHN), or Rh-deficiency syndrome.

More details and information here:

What is the Rh deficiency syndrome?