OK, I understand the basics of the ABO blood groups, and the various blood types that can result from the parents, but how about the Rh factors? Is this a case of dominant and recessive?
Of course it is; Rh+ is dominant, for the following reasons.
A given gene, in almost all cases, codes for a protein. When that gene is present and unmutated, the protein is present and effective. In the case of Rh factor, the protein is present (“Rh-positive”) or not (“Rh-negative”). If you have one copy of the gene, you’ve got the protein, so it doesn’t matter if you have one or two – that’s dominance. Only if you have NO copies of the gene can you be Rh-negative. Recessive traits are those that require the absence of a certain protein (or mutation) to show up; blue eyes, for instance, are recessive because it’s only possible to have blue eyes in the (near-total) absence of melanin, so if you have any genes for producing melanin, your eyes won’t be blue.
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Of course it is; Rh+ is dominant, for the following reasons…
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Yes, Rh follows dominant/recessive expression, but I think the “of course” explanation, which is accurate if parsed precisely, may also give a misleading impression to some readers (No offense to Nametag, whose explanation has an admirable brevity that mine will lack. In fact, many readers may prefer to skip this post. Proceed at your own risk)
For one thing, Rh is a straightforward dominant/recessive * but is NOT lke the ABO blood types* (or many other traits) as suggested by the OP. The A+ and B+ traits are each dominant over their respective (-) traits, but the ABO blood types themselves do not display dominant/recessive behavior: e.g. AB is not dominant over O; an offspring of AB and O parents may have any ABO type [A, B, AB, O]
Many traits also have multiple alleles (e.g. there are many diferent ‘flavors’ of hemoglobin gene that may occupy a specific gene site, and many people are various mixtures) and multiple copies (e.g. the HLA tissue types used in organ transplants: each person has several sites for these, and there are a large number of alleles [with cryptic names like H27) that may reside at each site.
A gene (by the molecular biology definition) does usually code for a protein, but a protein does not always translate directly to “a trait”, and some trait mutations aren’t in “genes” at all (by that definition), For example, a change in a control sequence would be inherited, just as genes are, and would produce effects by modifying the expression of ‘normal’ genes (changing the amount of gene product produced or changing the tissues they are expressed in, etc.).
Such control mutations may be called ‘genes’ in genetics, esp. if they produce a visible trait or syndrome .However, control sequences are NOT transcribed and translated into proteins. For example, enhancers may be sites with high affinity for a transcriptase, which therefore cause much greater expression of ‘nearby’ genes, even thousands of base pairs away.
Even if a gene does code for a protein product, the product rarely acts in isolation. more often it is one enzyme in a pathway containing many enzymes; a receptor that normally localizes to a certain area of the cell or a certain tissue; a structural or transduction protein that interacts with other elements; etc. Many DNA mutations that concern us today involve “knocking out” or restoring one element of a ‘normal’ pathway, but they’re a small part of the whole picture.
The overwhelming majority of genetic traits DO NOT display the straightforward “dominant/recessive” behavior cited in basic biology texts. Most traits we see every day aren’t simple on/off, but are multi-gene (e.g. complexion or hair color), multi-allele (e.g. the antibody tool kits that define the antibodies we’re capable of making are made of a handful of genes from a large universe of similar genes in he general populaion) , multi-copy (more than one copy of the gene exists on the same chromosome, creating more mix/match variability): or may have major environemtal components (height, IQ, schizophrenia, diabetes, cancer, etc.)
It just so happens that Rh+/- (almost always) results from the presence or absence of a single gene. Though not the rule, this is very common in the best explored syndromes and traits – but only because such traits or syndromes are exceptionally easy to unravel. We’re still taking baby steps – but like a baby, we’re growing and gaining capabilities with remarkable speed
As a matter of fact, there are at least three Rh genes (we test for them in the lab I work in) - RhC, D, and E. RhD is the most commonly clinically significant one, but pregnant women can have reactions to the RhC and E proteins as well. Someone’s RhD status is usually designated RhD+ or RhD-, but the other alleles are typically describes as RhC/c or RhE/e. There are also some variants of the Rhc allele out there.
Not of this really matters to most people, but it makes designing PCR tests for all the possibilites ridiculously complicated. If we wanted to test someone’s status for all three genes in our lab, we’d have to run up to eight separate assays.
Bad example, since the offspring of an AB and an O can only be type A or type B (barring chromosonal abnormalities). The AB parent must have the genotype AB, and the O parent must have the genotype OO. This means that all children will be either AO (phenotype A) or BO (phenotype B).
Right. It’s possible for an A phenotype and a B phenotype to produce any of the four phenotypes if their genes are AO and BO. Then you’d have:
A O
+---------+
B | AB | OB |
|----+----|
O | AO | OO |
+---------+
as possibilities.
Wow, I actually remembered something from ninth-grade biology class.
Thanks, Smeghead. I’d forgotten about the Rh allelic variants. I remember a real nightmare with minor Hb variant allelles back when I was training in Mol. Bio.
Also thanks to those who pointed out my error regarding AB/O crosses. I don’t know what I was thinking. It wasn’t even the example I originally meant to use.
I suppose this is the wrong crowd for me to do my usual penance of stripping naked and singing “If I Only had a Brain”.
Not necessarily. There’s a rare condition called cis-AB, where the person’s genotype is AB/x (where x can be either A, B, or O), rather than the more usual A/B. It can occur either because the person is carrying both an A and a B-allele on the same chromosome (due to an abberent crossover event in the past) or more commonly because they’re carrying a variant allele which codes for an enzyme that’s capable of attaching either a galactose molecule (giving type A) or an N-acetylgalactosamine molecule (producing type B) to the terminal sugar chain on the red cell membrane. A person with the genotype cis-AB/O is quite capable of producing a type O child.
(And we won’t even get into the “type O” people who aren’t really type O at all, nosiree…)
Suffice it to say the genetics of human blood types are a lot more complex than those introductory biology textbooks make them out to be!
Heh heh. We need a name for the rule that whenever someone says something “always” or “never” happens in biology, someone will be along momentarily with a counterexample.
I propose the name “Smeghead’s Rule”.
Also, a point that I found interesting is that the percentage of +/- in each blood type is not the same. About 65 % of people are + and 35 % -, but significantly less than 35 % of people of blood type B are negative, or so I’m told.
And since we’re talking about blood types and the like, please donate blood and/or platelets through the Red Cross or some other organization. 20 minutes of your time can save up to 3 lives with a blood donation. And I swear, it doesn’t hurt much.
I have a problem with my bloodgroup that seems to be rare. I didn’t do any research of my own on this, I just recall what I was told and what seems to be important in case I need a transfusion.
Short story: My mother was Rh - my father was Rh +.
Although every precaution was taken, something went wrong during the pregnancy. Something - some think it was a defect in the placenta - caused a bloodchange/-contact between my mother’s blood and mine. She started to develop Rh anti-corpses (forgot how that is called) at the sixth month of pregnancy. This caused the birth to be induced 3 weaks before time because my condition got critical (in uterus bloodtransfusion was not something that was an option at the time).
When I was born the doctor seems to have said: “Now I’m changing profession, I’m going to be a butcher instead of surgeon. That much problems and the child is Rh+” (he told me that himself… much later :). . )
The reason of his consternation was that despite everything my bloodtest showed Rh + at birth. One hour later it was Rh- and I had a bilirubine of 18. After the first transfusion it was 21 and went up to 23 after the second transfusion. In total I received 4 transfusions before the bilirubine went down (some doctors later found it possible that my dyslexia might be a left-over of that, and it seems that I can be grateful that I can even move and speak and function normally.)
It seems that what is explained to me as being “a positive Du factor” saved me from dying even before birth and caused the first bloodtest to show Rh+ .
Now I seem to have Rh+ when a normal bloodtest is done, yet I must receive Rh- when I need a transfusion. This can only be detected if a plasma-test is done.
Maybe this makes sense to someone with a medical background… ?
Salaam. A
Because of the dominant/recessive behavior of the Rh trait, it’s quite common for the offspring of a Rh- mother and a Rh+ father to be Rh+. A certain amount of “leakage” of fetal blood across the placenta is expected, and the mother may develop an immune response to the the Rh factor in her child’s blood. If this progresses, it can result in erythroblastosis foetalis or a destruction of the baby’s blood cells by the mother’s antibodies. This often doesn’t occur until the mother’s next pregnancy.
This was also called “yellow baby syndrome” because the baby lacked the normal pinkish coloration, and one breakdown product of hemoglobin is billirubin, which has a strong yellow color. Erythroblastosis foetalis is now less common, due to prenatal testing and preventative injections of antibodies that prevent the mother’s immune system from launching a response to the Rh+. Today, “yellow babies” are babies who have hyperbilirubinemia (too much billirubin) for any reason at all. The best treatment is simple sunlight, but in the topsy-turvy world of today’s Neonatal Intensive Care Units, we use high tech spotlights and IR units to replicate sunshine in the always darkened NICU. They even work almost as well as wheeling the infant out into a garden during the day.
Oddly, no one knows exactly how much billirubin is dangerous. IIRC, the magic number used to be 20 (it’s changed, because we use metric units these days) but that limit was based on one single, not very strong, study in the 1940s Once that number was out there, however, everyone was afraid to not treat at that level, so it became impossible to do any further studies. In neonatology this was called (IIRC) “dodekaphobia” - the irrational fear of the number 20- but we still don’t know what the real danger threshold is, or what factors affect it. Some babies (especially premature ones) have effects at lower levels, while others have no ill effects at much higher levels.
The syndrome is called “kernicterus” or “yellow staining of the nut (nucleus)”. “Nucleus” is a neurological term for “control center” containing the cell bodies of many neurons, whose axons reach to other parts of the brain. The specific nuclei we worry about in kernicterus are the basal ganglia - three “telephone switching centers” that fill the core of the brain [your thinking and processing occurs in a thin shell on the outside of your brain). They are important in motor control, which is why your doctor was so pessimistic. The billirubin apparently interferes with the myelin sheath which acts as “the insulation of the wiring” of the neurons.
Erythroblastosis foetalis and kernicterus are hardly the only consequences of Rh and other hemolytic reactions. They were historically important, and are still concerns, but today we monitor an array of other signs, like placental thickening, as well
The Du variant (aka “Duffy factor”) is a Rh-like factor that is only weakly detected by the Rh test (though standard testing today includes a separate Du test for women who test Rh-) Today, we consider Du+ mothers and babies to be Rh+, but with older tests it sometimes seemed as if the Rh status changed when current or past test results were compared to a patient’s clinical reaction. Other non-ABO, non-RH blood types like Kell, MNS and Kidd can also cause hemolytic (blood destroying) reactions in infants, or make Rh reactions worse.
Also, despite the incidences given by others, my books say that only 1% of Asians (e.g. Chinese and Japanese) are Rh- , increasing to 2% in Indo-Europeans (and also American Indians) and 15-16% in Caucasians. African Americans are about 4-8% Rh-, and the Basque are a whopping 30-35%. These are just rough guides, of course – “racial” designations always are. Individual testing is the touchstone.
I should warn you that I’m not at all an expert in this. I only know what I was taught in medical school (it’s been a while) and what I’ve picked up since. I’m sure Someone Smarter™ will be along shortly to explain that I have it all wrong.
Yes I know about this (many of my relatives including my parents were/are doctors or in an other medicine-related profession) and she did receive the needed antibodies before getting pregnant with me. There was also no sign of any abnormality, not one single reaction, in her blood during the first six months of the pregnancy. That is why the whole thing caugth everyone by surprize and why they think it might have been what was explained to me as " a feutal transfusion". By which they mean (I think) a sudden and rather extensive contact between my blood with hers.
I was not a “yellow baby” but a deep intense orange one (I have pictures and I look like one of those so called “blood-oranges”, oranges with a red shade on them). I had to hear on a regular basis that I was even more orange then an orange the first weeks of my life. They gave me the four transfusions and I was exposed to a special light etc… while in the incubator because I was born 3 weeks premature and was very much below the average weight.
My mother could not risk to become pregnant again because it was impossible for her to be exposed 9 months to the side-effects of the medication she had to take in order to have me survive until I could be considered viable (anti-histamine in a huge over-dosis and also something to help my longs develop faster because they knew I would need to get born premature).
It was also sure that even if she became pregnant the child in any case would not survive long enough to be viable. Or if by some miracle it would be born viable, it would be severely disabled. The amount of rhesus antigonism in her blood was as huge as if she would have had a whole house full of rhesus children.
As long as I live (31 years now) I always heard 21 as the high risk level and 23 as the absolute limit before suffering severe brain damage. My uncle who was a docter himself told me once that he had witnessed a child that had not passed 20 bilirubine, was not treated due to teh fact that the doctor did not saw the need and suffered that much brain damage that it could not even control its own limb movements. I heard similar stories from others about children coming above 21.
Whenever I tell my story to a doctor they react a bit surprized that I seem to be normal. (At the time I was even brought up as a curious case at colloquia. )
Thank you for the detailed explanation, I largely forgot all the details I ever asked and I dropped my intended medical education after the first semester. But what I still ask myself is if yes or no having twinbrother Dyslex as special birhtgift has indeed something to do with it. (As far as I know noboyd knows what exactly causes dyslexia.)
Yes, I know about the ABO cases, yet I was always told that these were less dangerous for the child. My mother had A type 1, but not Du +. As for being Rh - :She was Eu-Caucasian. (I still have her bloodtype identification)
From what I can remember of all of this: You got it all correct.
Salaam. A
Re-reading I see I got something rather confusingly wrong…
That must be reversed. I was Rh - at birth, whihc is why the doctor could not believe his eyes when reading the result. An hour later it was Rh + and then they found out abou the posivitive Du.
Salaam. A
Minor nit: Du is not the same as Duffy. Duffy is a separate, non-Rh blood group antigen system (which can, as you said, cause a major hemolytic transfusion reaction).
A Du (or “weak D”) person IS Rh-positve; they just express the D-antigen at very low levels on their red cell surfaces. The level of expression is low enough that it can be missed when standard cross-matching techniques are used, and the person may be mistakenly classified as Rh-negative. This causes no harm when the Du person is the one receiving blood, since it’s perfectly safe to give Rh-negative blood to an Rh-positive person.
But blood banks always perform a more sensitive test looking for Du before calling any unit of blood Rh-negative, because even though the amount of D-antigen on a Du person’s cells is low, it can be enough to trigger a hemolytic transfusion reaction if the blood is mistakenly given to a truly Rh-negative person who’s already sensitized to the D-antigen. (Unlike the ABO system, Rh requires at least one previous exposure before a person will develop dangerous antibodies to the “wrong” blood type.)
About 1% of Rh-positive individuals are weak Ds.
If you truly MUST receive Rh-negative blood when you have a transfusion, it’s possible you’re carrying a slightly mutated form of the D-antigen which is missing a small portion of the D-protein. The antibody used for blood typing can still bind to and recognize the protein as being a form of D, since it binds to an area of the protein that’s not affected by the mutation. However, the “normal” form of the D-antigen has a part that’s missing on this mutated form, and your body may have made an antibody to that area - which means that even though you’re D-positive, you’ll have a reaction if you’re given Rh-positive blood.
That’s assuming, however, that you truly DO need Rh-negative blood. People with the ordinary form of Du (who make the normal D-antigen, just in small amounts) are generally treated as though they are Rh-negative for the purpose of receiving blood, because testing for Du requires an extra step, and why perform it when there’s no harm in giving them Rh-negative blood? It’s easier on the blood bank to just consider them Rh-negative for transfusion purposes (but Rh-positive for donation purposes, since they do in fact carry the D-antigen!).
Is that the reason why the first bloodtest right after I was born showed me as Rh negative? But why were there no signs at all that I was indeed a Rhesus child? I was not yellow and my blood seemed to be Rh negative and normal.
And how do you explain that the bloodtest showed Rh positive an hour after I was born. I think to remember that this was the moment they went looking for the Du factor. My uncle told me later that the doctor doing the tests said: 'The moment you see only one little yellow spot on that child, start with the transfusions because he is a positive Du."
This started indeed when I was a few hours old (and my skincolour turned into deep orange) They started the first tranfusion yet it didn’t help to lower the bilirubine. I was told this is also exceptional: The bilirubine going up while and after transfusions are done. It stayed above 21 for more then a week and then started to drop slowly.
I also heard that it was impossible to determine a positive Du in Rh positive blood (but that information - like all the rest I remember of this - dates from years ago, so maybe it is outdated by better ways of testing.)
That is why merely the forming of antibodies in my mother’s blood surprized everyone that much in the first place. It was her first pregnancy and previously she never had any “contact” with Rh positive blood. In addition every precaution was taken to prevent her to react at an eventual “leaking” of cells through the placenta or whatever.
I think I was told something like that. If my blood ever comes in contact with Rh positive blood, it shall trigger a similar reaction as I had after birth. (red bloodcells destroyed by antibodies ?)
Oh nice… I am a mutant. My uncle nor anyone else ever informed me about the horrible details. Maybe because they all knew I was something alien before I was born. 
Salaam. A
Yes. The first blood test was done using the standard blood typing technique, and on a standard blood type a Du person will show up as Rh-negative. It takes a second, more sensitive test to detect Du.
You weren’t yellow because bilirubin hadn’t had time to build up in your body yet. While you were in utero, your mother’s body had been excreting all the bilirubin that the destruction of your red blood cells produced.
And you seemed to be Rh-negative on the first blood typing because the blood bank did the standard typing, not the more involved one needed to detect Du.
You said it - they went looking for Du. An hour after the first test, the blood bank no doubt had been given much more information about what was going on, so they set up the special testing needed to look for Du and re-typed your blood - and sure enough, they found you WERE a Du, and thus Rh-positive.
You obviously had a lot of anti-D antibody in your blood, to cause so much red cell destruction!
I’m not sure what the person who told you his was trying to say. Du IS Rh-positive blood; it’s just positive at a lower level than “normal” Rh-positive blood is.
There must have been significant leakage of your blood across the placenta fairly early in the pregnancy, despite the precautions. Normally, the barrier between the maternal and fetal circulation is very strong, but there can be some leakage during labor and delivery. That’s why the first pregnancy generally goes well, but later ones may have problems - Mom’s immune system “saw” the first baby’s blood only during labor, and made antibodies against it which are ready and waiting to attack the next Rh-positive fetus.
But if early during that first pregnancy, the Rh-negative woman’s immune system “sees” the Rh-positive baby’s blood, there’s enough time remaining in the pregnancy for the anti-Rh antibodies the woman’s immune system makes to cross over and attack the first baby, too. That’s what happened to you.
(Today, Rh-negative women who are pregnant are not only given Rhogam after labor to prevent them from forming anti-Rh antibodies, they’re also given it at intervals during the pregnancy and emergently after trauma (such as a car accident) just in case such “early exposure” to the baby’s blood should happen.)
If you’re a true Du, that’s not likely. Most Du individuals don’t make anti-D antibody (because it would attack their own cells). Blood banks just give them Rh-negative blood because they will type as Rh-negative on the standard blood typing test, and the blood bank has no particular reason to go looking for Du. It’s more convenient to just regard them as Rh-negative for transfusion purposes.
However, in rare cases a Du person may make anti-D antibodies. And if they do, then they MUST receive Rh-negative blood or they’ll have a transfusion reaction. You may be one of those rare cases. (Or a mutant! 
)
Thank you artemisfor refreshing my memory so well and filling up a few wholes in my own medical past and - situation.
I seem to remember that this was the reason for the medication she had to take.
My uncle- who supervized my education after my parents died - always said I was self-destructive when he was angry because of something I did. An other riddle solved… It was never my fault. I’m born like that.
I always told him that but that never could impress him in a positive way. Yet he should have known. He was a doctor ! He was there during that whole messing around with me my first weeks as a human. I feel so… OK, I’m an adult now, I can handle this injustice and get over it.
It can also be something that is wrong with my memory, that being no surprize for someone who knows me.
Yes that is what was supposed to be the cause, as far as I recall.
That is what I was told since I was a child. It caused a few nightmares in which I saw doctors with a very satanic grin and bloodsacks in their claws bending over me with long needles… and such stuff… (I’m over that faze now).
I also used to have some sort of medical identification card somewhere in my belongings whenever I left home (I suspect that somehow this still manages to follow me around) which of course made me feel as if I was somehow disabled or as if I was very special. This depending the circumstances and also the audience at whom I played that card out myself.
" You can’t hit me because you are going to make me bleed and I can’t have a bloodtransfusion and my uncle is going to kill you if I bleed to death" was a useful line to keep my cousins off whenever I faced strong and united opposition to my claims that something they had was in fact mine (I truly had such an inborn inclination to strive for peaceful solutions ) .
Nobody at home ever doubted that I was a rare case. They still claim that they are convinced of that. But now that I received such detailed information that was hidden for me, I think that they are wrong and that they know it. Because I am now more or less convinced that I am a mutant.
Do you have by accident some info on the question if yes or no Twinbrother Dyslex showed up as extra birthgift because of all of this?
Salaam. A
Aldebaran, I don’t think there’s any way to know whether your rough start in life is related in any way to your dyslexia.