A Jordanian family with three sisters apparently homozygous for Mkand evidence for clinical significance of antibodies produced by MkMkindividuals.
The rare MkMkphenotype is the result of a deletion of the coding regions of both GYPA and GYPB. Red blood cells (RBCs) of individuals homozygous for the rare Mkgene lack all MNS blood group antigens and have no glycophorin A or glycophorin B. This phenotype is extremely rare and only four families have been reported.



A 28-year-old woman was referred for assessment of recurrent early neonatal deaths. She was found to be apparently homozygous for Mk. With the presence of two MkMksisters as matched donors, an intrauterine transfusion was performed to treat fetal anemia due to a strong maternal atypical antibody. Twins were delivered and subsequently transfused with RBCs from the proposita and her MkMksisters.



This case reports the fifth family with members apparently homozygous for Mkand the second example of severe hemolytic disease of the fetus and newborn (HDFN) due to maternal antibodies produced by MkMkindividuals. It also shows the importance of intensive monitoring and management of HDFN caused by alloantibodies to RBC antigens.
Department of Medical Laboratory and Forensic Medicine, Division of Blood Bank, Jordan University Hospital, Amman, Jordan.
Nour Al-Huda
NA
Al-Jada
D000328:Adult; D000740:Anemia / Q000097:blood / Q000235:genetics / Q000628:therapy; D001483:Base Sequence; D001805:Blood Transfusion, Intrauterine; D004899:Erythroblastosis, Fetal / Q000097:blood / Q000235:genetics / Q000628:therapy; D017707:Erythrocyte Transfusion; D005260:Female; D006021:Glycophorins / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D007518:Isoantibodies / Q000097:blood; D007597:Jordan; D008951:MNSs Blood-Group System / Q000097:blood / Q000235:genetics; D008297:Male; D011247:Pregnancy; D017384:Sequence Deletion
C409972:GYPA protein, human; C409973:GYPB protein, human; D006021:Glycophorins; D007518:Isoantibodies; D008951:MNSs Blood-Group System