First report of known rare rhnull phenotype individuals in Iran

Background

The Rh-deficiency syndrome is a rare genetic disorder of red blood cells (RBCs) with a reported frequency of approximately 1 in 6 million individuals, transmitted via an autosomal recessive mode generally via consanguineous genealogy. It results in the same clinical syndrome characterized by chronic hemolysis of varying severities, with stomatocytosis, spherocytosis, increased osmotic fragility, altered phospholipids asymmetry, altered cell volume, defective cation fluxes, and elevation in Na+/K+ ATPase activity

Methods

The Patients extended phenotyping showed that they were negative for D, C, E, c, e RBC antigens, indicating they were strongly suspicious of being the rare Rhnull phenotype.Adsorption and elution studies in Anti-human globulin did not reveal the presence of D, C, E, c, e, RBC antigens in the blood obtained from both patients. We performed Rh phenotyping with two sources of antisera. Positive and negative control tests were performed for each antigen according to the manufacturer"s recommendations. Based on these collective findings, we interpreted these results as being strongly suggestive of the Rhnull phenotype with a clinically significant anti-Rh29 identified in serum of the female patient

Results

Rhnull phenotype is a rare blood group with a frequency of approximately 1 in 6 million individuals, transmitted via an autosomal recessive mode. It is characterized by the weak (Rhmod) or lack (Rhnull) of expression of all Rh antigens on the red cells. The clinical significance of its assessment is that such patients with Rhnull syndrome are associated with chronic hemolytic anemia of varying degrees. Another clinical importance is that such subjects readily form alloantibodies when exposed to Rh antigens.We report herein a rare Rhnull phenotype in a sibling, which was detected as a part of the difficult sample work-up for red cell antibody screening and identification.

Conclusion

Availability of a National Rare Donor Program and support of well-trained reference laboratory personnel in a close collaboration with relevant medical team help to manage a patient"s need to a very rare Rhnull phenotype in an acceptable turnaround time. In this study, the patient"s life was saved by her brother"s compatible Rhnull blood. After consultation with his brother, he consented to be added to the list of National rare donor registry database in Iran.

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