Cis AB

Cis AB is a rare ABO Blood group antigen genotype which is phenotypically almost the same as AB. In Cis AB inheritance A and B antigen seem to be segregating as if they are in very close loci on the same chromosome. These can happen due to mutant alleles at ABO locus (multiple variants are available). Usually it is a single allele making a single enzyme which can make both A and B antigens.[1] Antigen expression is weaker than A1 or B.

Contents

Scenarios

When one parent carries a Cis AB allele, the other allele can be any of O, A or B and the phenotype of this parent is anyway AB, but the children will inherit either the AB or the other allele from this parent.

  1. If the other parent is O phenotype (OO genotype) there can be three likely scenarios for blood group of children of a Cis AB carrier (and a 4th very unlikely scenario):
    1. The second allele is O: children are either AB or O
    2. Second allele is A: Children are either AB or A
    3. Second allele is B: Children are either AB or B
    4. A very rare 4th possibility exists: if the other allele is also Cis AB then the children will be always AB irrespective whatever the other parent is, because they will have one cis AB allele from this parent.
  2. If the other parent is A, depending on whether this parent is genotypically AA or AO and what the other allele is in the Cis Ab carrying parent, there are following possible scenarios:
    1. Other parent is AO and second allele is O: The children are either AB or A or O
    2. Other parent is AA and the second allele is O: The children are either AB or A
    3. Other parent is AO and second allele is A: The children are either AB or A
    4. Other parent is AA and the second allele is A: The children are either AB or A
    5. Other parent is AO and the second allele is B: The children are either AB or B
    6. Other parent is AA and the second allele is B: The children are always AB
    7. Rare situation: If the other allele is also cis AB:The children are always AB
  3. Like wise there will be similar scenarios for the other parent being B:
    1. Other parent is BO and second allele is O: The children are either AB or B or O
    2. Other parent is BO and second allele is A: The children are either AB or A
    3. Other parent is BO and the second allele is B: The children are always AB or B
    4. Other parent is BB and the second allele is B: The children are either AB or B
    5. Other parent is BB and the second allele is O: The children are either AB or B
    6. Other parent is BB and the second allele is A: The children are always AB
    7. Rare situation: If the other allele is also cis AB:The children are always AB

(Caution: ABO inheritance is generally derived assuming the children are not the very rare Bombay phenotype which would require both parents to be carriers of it.)

Real life implications

Maternity and paternity disputes

There can be paternity or maternity disputes if tested by ABO blood grouping. Those of the above scenarios where a child's phenotype is written in bold will be such a situation. For example (scenario 1.1 above) a child of a cis AB (who will apparently look as a regular AB phenotype) individual and an O individual will be either AB or O instead of the usual A or B (see diagram above).

Differential diagnosis

If the child of an AB and an O individual is O (the green colored offspring in the scenario 1 image above), then a rare alternative possibility is that the parents were carriers (heterozygous) for the Bombay phenotype (Hh) and the child is a Bombay (hh) homozygous by genotype thus expressing Bombay phenotype also called Oh where irrespective of the presence of the ABO alleles the substrate from which those antigens are made is not made and thus A, B and even O antigen is completely absent.

References

  1. ^ Mark H. Yazer, Martin L. Olsson, Monica M. Palcic, The cis-AB Blood Group Phenotype: Fundamental Lessons in Glycobiology, Transfusion Medicine Reviews, Volume 20, Issue 3, July 2006, Pages 207-217, ISSN 0887-7963, DOI: 10.1016/j.tmrv.2006.03.002. (http://www.sciencedirect.com/science/article/B75B5-4K6R7W1-8/2/31e62338a662627d515cd7d647cba531) doi:10.1016/j.physletb.2003.10.071

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Look at other dictionaries:

  • cis — cis·andine; cis·co; cis·gangetic; cis·jurane; cis·lei·than; cis·mon·tane; cis·pa·dane; cis·pon·tine; cis·rhe·nane; cis·sa; cis·sam·pe·los; cis·sie; cis·sing; cis·soid; cis·sus; cis·ta·ce·ae; cis·ter·cian·ism; cis·tern; cis·ter·nal;… …   English syllables

  • cis- — ⇒CIS , élément préf. Élément préf. signifiant « en deçà de », formateur de composés subst. ou adj., princ. en géogr., en anat., chim. et phys. Anton. trans . A. GÉOGR. (v. aussi cisalpin, cismontain, cisrhénan empruntés au latin) : cisgangétique …   Encyclopédie Universelle

  • CIS — bezeichnet: Cis (Trentino), eine Gemeinde im italienischen Trentino cis (diesseits, im Gegensatz zu trans) bezeichnet: geografische Angaben wie zum Beispiel Cisjordanien, Cisleithanien in der Stereochemie eine bestimmte Anordnung von zwei… …   Deutsch Wikipedia

  • Cis — bezeichnet: Cis (Trentino), eine Gemeinde im italienischen Trentino einen Teil der Cis trans Isomerie ein Cis Element in der Genetik den Ton C, der um einen Halbton erhöht wurde; siehe Tonleiter den über Cis gebildeten Dur Akkord; siehe Cis Dur… …   Deutsch Wikipedia

  • cis — [ sis ] adj. • position cis 1895; du lat. cis « en deçà de » ♦ Chim. Se dit d un isomère organique dans lequel les atomes ou les radicaux sont situés du même côté de la molécule asymétrique. Isomères cis et isomères trans. ⇒ cis trans, cistron. ⊗ …   Encyclopédie Universelle

  • cis- — [lat. = diesseits]; 1) Abk.: c ; Syn.: (Z) : kursiv zu setzender Stereodeskriptor zur Beschreibung der Stereochemie von org. Verb. oder Koordinationsverb. sowie von Reaktionsweisen. Zwei Gruppen, Substituenten oder Liganden stehen cis zueinander …   Universal-Lexikon

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  • CIS SR-88 — Файл:Rifle SR88.jpg SR 88 Тип: автомат Страна: Сингапур История службы …   Википедия

  • Cis — puede referirse a: Cis, localidad y comune italiana de la provincia de Trento. Ácido graso cis Isómero cis Cis, un género de insectos coleópteros. CIS puede referirse a: Centro de Investigaciones Sociológicas, de España. Copa de la CIS …   Wikipedia Español

  • cis- — prefix 1》 on this side of: cislunar.     ↘historical on the side nearer to Rome: cisalpine. 2》 closer to the present: cis Elizabethan. 3》 Chemistry (usu. cis ) denoting molecules in which two particular atoms or groups lie on the same side of a… …   English new terms dictionary


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