The rare Lutheran blood group phenotype Lu(a-b-): a genetic study.

Area of Science:

• Immunogenetics
• Hematology
• Population genetics

Background:

• The Lutheran blood group system is complex, with the Lu(a-b-) phenotype having at least two known genetic causes.
• Understanding the genetic basis of rare blood group phenotypes is crucial for transfusion medicine and population studies.

Purpose of the Study:

• To investigate the genetic cause of the Lu(a-b-) phenotype in a large cohort of blood donors.
• To determine the frequency of the Lu(a-b-) phenotype and its genetic backgrounds in South East England.
• To explore potential genetic linkage between the inhibitor gene and other blood group loci.

Main Methods:

• Analysis of blood donor data from 250,000 individuals.
• Family studies of 41 individuals with the Lu(a-b-) phenotype.
• Lod score analysis to assess linkage between the In(Lu) gene and other blood group loci.

Main Results:

• The Lu(a-b-) phenotype occurs in approximately 1 in 3000 individuals.
• The dominant inhibitor of Lutheran antigens, In(Lu), was identified as the common cause in South East England; no cases of the recessive LuLu background were confirmed.
• Lod score analysis suggested a possible linkage between In(Lu) and the Rh blood group locus.
• The study confirmed the suppressing effect of In(Lu) on unrelated antigens like P1, Aua, and i.

Conclusions:

• The dominant inhibitor gene, In(Lu), is the primary genetic cause of the Lu(a-b-) phenotype in South East England.
• Further research is warranted to confirm the linkage between In(Lu) and Rh and to fully elucidate the genetic mechanisms involved.
• The findings contribute to a better understanding of Lutheran blood group genetics and antigen expression regulation.