Junior blood group system

Add links
Source: Wikipedia, the free encyclopedia.
ABCG2 (Junior blood group antigen)
Identifiers
SymbolABCG2
Chr. 4 q22.1
Search for
StructuresSwiss-model
DomainsInterPro

The Junior blood group system (or JR) is a human

transfusion reactions and hemolytic disease of the newborn on subsequent exposures. Jr(a) negative blood is most common in people of Japanese heritage.[2]

Genetics

Autosomal recessive inheritance

The gene

null mutation of ABCG2 express this phenotype.[1] Homozygosity for certain missense mutations, or heterozygosity for a missense mutation and a null mutation, can result in a weak phenotype with decreased expression of Jr(a) antigen.[2][3] As of 2018, over 25 null and weak alleles of ABCG2 have been described.[4]

Epidemiology

The highest rates of the Jr(a) negative blood type have been reported in Japan,

Niigata region to 1 in 3800 in the Tokyo region.[1] Additionally, a number of cases have been documented in European Romani populations.[6] The Jr(a) negative blood type is very rare in America: a study of 9,545 Americans failed to identify any Jr(a) negative individuals.[5]

Clinical significance

Anti-Jr(a) antibodies are generally composed of Immunoglobulin G and develop when individuals are exposed to Jr(a) positive blood through pregnancy or blood transfusion. Some cases of anti-Jr(a) have been reported in patients who have not been previously transfused or pregnant.[2][5]

Jr(a) is more strongly expressed on

crossmatching) may be suitable.[5][4] It is difficult to secure Jr(a) negative donor blood due to the rarity of this blood type.[6]

ABCG2 is a uric acid transporter, and the Jr(a) negative phenotype is associated with gout in Japanese populations.[8]

Laboratory testing

An individual's Junior blood type can be determined by

DNA testing may be impractical due to the high number of mutations affecting Jr(a) expression.[9]

Anti-Jr(a) antibodies are most easily detected by the

ficin or papain.[2]

History

The Junior blood group system was discovered in 1970 by researchers Stroup and MacIllroy, who reported on five patients whose blood was incompatible with all samples tested except each other's. They named the causative antigen "JR" after Rose Jacobs, one of the five patients — the common name "Junior" is in fact a misnomer.[2]

In 2012, two research groups[6][10] independently identified ABCG2 as the basis of the Junior blood group system. The Junior system was officially designated a blood group by the International Society of Blood Transfusion that year.[11]

References

  1. ^ a b c Kniffin CL (2013). "OMIM entry # 614490 – Blood Group, Junior System, Jr". Online Mendelian Inheritance in Man. Retrieved 1 September 2019.
  2. ^
    S2CID 24659443
    .
  3. S2CID 2562261
    .
  4. ^
    S2CID 52933848. Archived from the original
    (PDF) on 2021-07-13. Retrieved 2019-09-17.
  5. ^
    ISBN 978-1-118-49354-0
    .
  6. ^
    PMID 22246505
    .
  7. PMID 31324575
    .
  8. ISBN 978-0-323-50971-8
    .
  9. S2CID 3229027
    .
  10. S2CID 20854378
    .
  11. S2CID 84328440
    .
Retrieved from "https://en.wikipedia.org/w/index.php?title=Junior_blood_group_system&oldid=1212912664"