August 13, 2003

Human chimeras & mosaics

Miscegenation taken to the extreme -- and it may be more common that anyone realized:

Eight years ago in Britain, a boy was born who, genetically, was two people. He was formed when two eggs, fertilized by two different sperm, fused into one embryo inside his mother's womb.

He was an unremarkable baby. But as a toddler, doctors discovered that he was a hermaphrodite - what was originally diagnosed as an undescended testis turned out to be an ovary, a fallopian tube and part of a uterus. Further investigation revealed that some parts of his body were genetically female but the rest, which contained a different combination of his parents' genes, was male.

The boy, who was otherwise healthy, is one of only a handful of known true human chimaeras - people carrying tissues that originated in two separate embryos. More common are mosaics, who have patches of tissue that differ genetically from the rest of their body, thanks to a mutation or chromosomal anomaly that arose early in embryological development.

The frequencies of chimaerism and mosaicism are unknown, but doctors might benefit from a better understanding of both conditions. In recent years, tantalizing hints have emerged that pockets of genetically mismatched cells may contribute to conditions as common as infertility, autism and Alzheimer's disease. . .

And if chimaeras and mosaics are more common than we realize, they will complicate future efforts to tailor drug treatments to people's individual genetic constitutions. Two genetically different tissues in one body might produce an unpredictable response to a drug, speculates Roland Wolf, who studies pharmacogenetics at the University of Dundee, UK.

From last year's Nature; belated spotted via Katrina of Isfogailsi

Posted by David on August 13, 2003 10:26 AM

Comments

i am a chimera and i was told i could live to about 35 with good health and luck, i am now 30 and i feal like shit all the time.

the only other chimera i knew was a scitzo and generally an unpleasant man, i was told that chimeras are prone to being scitz(oh bugger).

it took me ages to find something on the net actually confirms that chimeras are real, cool.

Posted by: depends on February 14, 2005 11:01 AM

My name is Christofer im a 23 year old male Born in Oregon state USA. I am a case of a Vanishing Twin. Although i dont know if i carry the physical traits of a Chimera I am going to be tested. I was born with extra body parts two fully functional stomachs which my body rejected one at the age of 11. I am very intrested in these studies and any help someone might be able to offer me on how to apporoach this subject with my physician to get tested. Also im showing no signs of any kind of mental disorders other than standard stress. In fact i handle life pretty well and am in great physical condition. as i maintain the physical standards of the US Army ...again if anyone has any help to offer or information on the chemical/medical information id be pleased to check it out

Posted by: Christofer Pawley on July 20, 2005 3:58 AM

Hi Christofer, I recently watched a show on TLC discussing symptoms and tests for Chimeras. What I did learn is genetic DNA testing on you and your children. If a DNA tests comes up neg, have tests for your siblings.Although, I did learn this from this show based on a Mother that did not match her childrens DNA. Hope that is of some help to you. I'm interested in learning more about Chimaerism. Please feel free to email me. Thank you, Angela Marrs

Posted by: Angela Marrs on August 21, 2005 7:29 PM

i was born a hermaphrodite, i discovered later after a trip to a special doctor and a room full of uv lamps and a mirror that i was also a chimera, the sight of moving blueish tatoos under my skin made me feel connected to the other voice, it is silent but i feal what he says to me, he is like an animal but he is soft for me, i know that sounds weird but i love him and in some sci fi way i always wished we could be seperate so i could be with him.

Posted by: rather not say on October 25, 2005 9:02 PM

Is it possible for a chimera to have two different blood types, and if it is possible, could they survive?

Posted by: Anonymous on December 29, 2005 12:02 AM

I am not sure of the explanation for me. I was born with a what was considered a birthmark at the time, but has moved and changed as I have gotten older. Half of my skin and hair is a different pigment and color. When I was a kid, I had a larg black spot in my hair and it is still there but has spread somewhat to cover half of the back of my head and a little over my ear. The funny thing is that a few years ago, My chest hair started to change - it is now black on the left side and blonde on the right. I also have several darker areas on my skin in different places on the left side. I would really like to know what the hell I am. An explanation would help me cope with the fact that I look like a carny! Any imput would be greatly appreciated.

Posted by: Scott on February 13, 2006 3:58 PM

@Depends:

I dunno if chimeras are prone to being "schitz", although it could be that there are two souls stuck in the same body... yikes! I suppose that may actually be the case for "Rather Not Say".

@Cristofer:

Chimeras are formed from two different fraternal embryos that merge... if your vanishing twin was your identical twin, it wouldn't show up in the genetic testing, so you might get a false negative... just giving you a heads up!

@Anon:
Yes, and yes... if the body adapts to one embryo having type A blood and the other type B (which reject each other), it would be sorta like (for example) a normal person having type AB blood. Of course, it may not adapt, causing a miscarriage... but sometimes it can.

Posted by: Brendan on May 29, 2006 10:36 AM

Hello. I am wondering if I might be a chimeras or mosaic. I have a lot of stretchmarks on my body as if my skin is tooo small for my skeleton. And I have two very different sorts of hair on my head. Does this ring any bells with anyone? I am considering getting genetically tested. Thanks Paul. Amsterdam, EU.

Posted by: Paul on June 15, 2006 5:23 PM

If you want to get tested, and don't know how to begin, contact your nearest large children's hospital, and ask to speak to the Genetics Department. Might be called Birth Defects Department. They do a lot of genetic testing. They may even be interested in the occasional adult with an unusual condition. But they will know where the right people are to help you.

Describe your presenting symptoms, and tell them you want to be tested to determine if you are a chimera or have mosaicism. Ask where you can go in your area to have the testing done.
Your GP may not have a clue about such conditions.... but you probably already know that.
Good luck

Posted by: Lois Walker on July 12, 2006 12:00 PM

I have strange skin pigmentation, and have no clue what it could be. It is most noticable on the back of my legs. On each leg it seems like a line is drawn and the skin is lighter on the inner part of both legs. Does this sound familiar to anyone? Even the hair growth is thiker on the darker side.
Thanks, Beth

Posted by: Beth on July 29, 2006 11:56 AM

In the last 4 years, my doctors have detected the presence of a nearly complete opposite-sexed reproductive system in my pelvis, to go with the half-a-system I already knew about. And retested everything to the point of absurdity. A spot check of dna from the structures in question, was refused by the urologist I was referred to. At this point, they won't diagnose, and just shake their heads at how much sickness I'm in. They've chosen to claim that I've somehow faked-out the bloodworks and mris and cat-scans.

One thing that leads me to wonder about chimerism, is that a gastroenterologist I was referred to, found that I have a seperate section of colon branched off from the main digestive tract.

I've been feeling like hell. I wanted them to help me, not take notes while they watch me die.

Posted by: Anonymous on August 6, 2006 8:42 PM

To Beth,

There is a possibility that you may be a hermaphrodite, which is a form of Chimerism. There is a lot of good information on www.Wikipedia.org, just search for Chimera. I hope all is well with you.

Posted by: Dee on September 27, 2006 6:19 PM

Dee-

I think you replied to the wrong post. I know I'm not a hermaphrodite(being I only have 1 set of reproductive organs) and Have 1 child with another on the way.

Posted by: Beth on September 29, 2006 12:56 PM

I have strange situation. I was told when I gave birth to my daughters that they were identical twins. They never looked identical to me, but the doctor said they were because they had the same placenta. They both have been stricken with strange health issues since birth. One (Twin A) has Lymphomatoid Papulosis ( an extremely rare skin cancer). She also has Dysthymia ( a form of chronic depression) She suffers from abdominal migraines ( a condition where instead of getting the pain in her head she throws up profusley).

The other twin ( TWIN B) has different issues. She has unexplained pain in her right hand that has causes her hand to cramp for unexplained reasons, turn blue, and is sometimes cannot be used. The doctors provided carpal tunnel surgery release as a antidote for the pain, but they made it clear that she did not have carpal tunnel. They don't know what is wrong. She has unexplained low- grade fevers. Unexplained pains in her back and sides. Strange dots of what appears to be pin dots of blood under her skin that come mysteriosly and leave mysteriously.

The doctors can't tell me why my daughters have these things. All they ever say is "It is rare."

Recently I was looking at TWIN B's back because she said her back itched and she wanted me to scratch it. I noticed a strange birthmark. That I had not seen when she was younger. The marks looked like huge stripes of light pigmentation. I would say stretch marks, but they didn't have the deep groove that (unfortunatley) I know stretch marks leave. The look much like huge wings or some mythical dragon fluorescent tatoo on her back.

My twins are alive. Could there have been another child? Could TWIN B or both of them be a Chimeras?

Posted by: Kimberly on December 11, 2006 4:57 PM

you are humans none the less a new breed and species that will one day become a major asset to humankind you should all feel proud and though i cannot feel youre pain i stand beside you all hopeing for the best.

sincerly,
chiefleader
uniting earth one race at a time.

Posted by: chiefleader on January 10, 2007 11:29 AM

is there any way that i could of inherited mt sisters dna when she had died in the womb and i had servived. or could my mom have done th same.

Posted by: Brandon Hines on September 21, 2007 8:41 PM

Hi my name is Niky. I'm a student in Puerto Rico, recently I was given a biology assignment in genetics; I choused DNA mutations, on account of the Chimera, now I'm not really sure how to do my thesis because of the very vague details of the disease. I would really love if someone would explain to me what really goes on, genetically speaking, is it a mutation? Does it express symptoms? And any other detail? please if you know a little more about the disease and how it?s manifested write me, my assignment is for November 9, 2007.
Thanks

Posted by: Niky on November 1, 2007 3:31 PM

A word of comfort to all other Chimeras out there.
We may be more common than people think. I was diagnosed about nine years ago. I am now 70, but look and have a body and mind of someone of mid thirties.

Blood tests revealed that I have two immune systems, that do not reject each other, I suppose my other me adapted to us before we were born and we are used to us by now. Half my cells are xx and half are xy. When I was born I was registered as a boy, when my Daddy was called up during WW2 my Mummy had me live as a girl, when I was seven my Daddy came home and I had to be a boy again, at the same time I got all the childhood infectious diseases one after the other and spent six months in bed, I had to re-learn how to walk again and my balance was impaired. I did manage to learn to ride a bike (I had to think about balancing or I fell off) and do all the boy things and grew up, went to grammar school, won a State Scholarship to University and did a Degree. I even got married and fathered two daughters.

Suddenly in my fifties I began to change appearance, and I am now mostly female, with breasts, and long hair down to my shoulderblades, small waist, high voice, an opening where there was only a depression before down there and a shrunken former penis that is like a clitoris. I have to sit to pee, and have periods, which at 70 is pretty unusual and a bore. Apart from all that I am healthy. As I studied Biochemistry and worked in the Pharmaceutical Industry, at one time delevoping new medicines and then managing clinical trials, I have some medical knowledge and where I now live I do not let the somewhat basic standard medical people get at me - I can manage my own health pretty well and with two immune systems to defend me most bugs have little chance!

In Germany, where I was investigated and had my condition finally diagnosed, I was told that I was not unique, there were an estimated 500 or so others, but most were in China. I have been unable to verify this or gather further information about it.

I live as a woman now, but still sometimes have trouble with Authorities, who cannot understand such an unusual person as I am, and can make obstacles, like over licenses, pensions, and passports. I got around that last one by buying an alternative one in the Free Market, and am now not only a Brit but also a Mauritian. (My Daughters joke that I am a MARTIAN!)

No two people - even chimeras - are the same, and much depends on how well mixed up one's cells are, but I am living proof that one can live a healthy, useful life with this unusual condition. I have two PhDs and have made quite a few contributions to medical research and scientific knowledge in my time already, besides having two daughters and three grandchildren, written two books and been twice married, lived and worked in six different countries and learned seven different languages.

So please take heart and do whatever you feel you want to and don't let ignorant bigots and even well-meaning but useless, uninformed people mess you up. Just be YOU, you are Special.

Good luck to all and may you all be as blessed as I am.

Briar

Posted by: Briar on December 4, 2007 5:18 PM

Can a fraternal twin be a chimera from a father's side and that when the child of the father does a YDNA test, that the YDNA of both the father and the son do not identify the YDNA of the son's grandfather? My mother was having twins but twice before my twin and I's birth were supposedly vanishing twin situation or adoption outside the family of the "other" twin. My mother was pregnant in July 1967 and thereafter miscarried by Sep 1967. I was born prematurely in April 1968. Could it be that the miscarried child or twins' DNA was carried by my mother and then passed to us. And therefore we have YDNA that shows a different father's YDNA being that the father of the miscarried child or set of twins was different than ours? My father was RH+ and his mother RH- almost killing him. Grandma got pregnant after my father and was told she would not survive if she tried to go full term so baby was aborted. My father and I go back and forth when testing our blood types from being O pos to O neg etc. Anyone know if chimera or mosiacism affects the YDNA testing results? Email me at douglaslloydbuchholz at yahoo dot com please or doulgaslloyd at verizon dot net

Posted by: douglas lloyd buchholz on December 15, 2007 4:25 PM

I have been searching for a site to "connect " to and found this one. I am looking for a source for testing of Chimera or Mosaic DNA (if that is the proper term). Hopefully someone will see this and point me in the right direction...
Info:
I have a line down the middle of my stomach from my breasts to my belly button in the shape of a large triangle that does not tan. I also have lines down both calves that one side tans lighter than the other.
I see colors differently in both eyes, one lighter than the other and I see more clearly outside.
I have a dual "whirl loop" on one of my fingerprints.
I go from emotional extremes if I have been asleep and woken up unexpectedly.
Mentally, I have always been unfulfilled, like I am missing something, meaning. I'm not sure if that means anything but, I am just being honest.
I have been diagnosed with allergies that no longer exist for me, no symptoms.
I am RH negative and my mother is a fraternal twin. I also know that I am Swedish, French, German and Native American (Blackfoot Indian) Descent.
Any info or point in the right direction would be greatly appreciated as I have been dealing with episodes of depression lately.
Nicole
P.S. Please don't confuse me as a social misfit as I have a very successful job and home life, etc. I just have this lifelong question......

Posted by: Nicole on January 9, 2008 10:41 PM

Hello I am researching chimera for a project and I was wondering if you had any other stories/pictures of real known chimera vicitms.
thank you,
Christina

Posted by: chrisitna on February 24, 2008 9:04 PM

This message is for Nicole.

Hi Nicole, my name is Tayler.

I really related to everything you said and I'd like to tell you my story as well. Do you have an email address I could contact you at?

Posted by: tayler on March 6, 2008 5:15 PM

Scott - I know how you feel. All the hair color on my head is split down the middle. When you've grown up with this "defect" it's easy to forget about ... until you notice someone obviously staring at you. I've always joked that if my career path didn't work out I could grow a beard, join the circus, and be the world's greatest bearded lady.
I've always wanted to have my dna tested. Does anyone know how much something like that costs?

Posted by: Samantha on May 5, 2008 2:08 PM

I had never heard of a Chimera until I was called one. I was told that I most probably started out as a mirror twin and that he egg didn't completely split. Externally my left side is smaller and weaker than the right. I have very little feeling in that side and it is a few shades lighter than my right side. Internally the organs on my left side are healthier and larger than the right side. I have two extra ribs, my heart is backwards,I only have four lumbar vertebra and disc, my reproductive organs were very small, and I had a tooth in my sinus. These are just a few of the problems that have been found over the years. I never catch colds or the flu, but I can be healthy as a horse one day and at deaths door the next and usually with no sure explaination. Recently I had a light stroke that has everyone puzzled. It could be small vessel disease, but I have been checked from head to toe and all my major and medium arteries are clear with no build up at all and I don't have high blood pressure. I get really tired of seeing the doctors shrug and throw up there hands and most of them don't want to hear about Chimeras.

Posted by: Anonymous on May 16, 2008 10:57 PM

I saw that some of you had posted about unusual lines of pigmentation on your skin. There is a rare skin disease called Blaschko's Lines, or the Lines of Blaschko. You might look into it, it sounds really similar.

Posted by: Lindsay on June 20, 2008 1:17 AM

I am pregnant,now 33 1/2 wks I am strongly concerned about the father of my child. After almost three years of being with him I am now finding out about alot of lyes he has told me. My concern is if he might be chimaera, and is there anyway of me finding out. Is there any signs to look for and if he denies paterninty is there a test that can be performed! Thank You in advance

Posted by: rita on July 2, 2008 12:10 AM

this article is weird to me. i'm 18 yrs old and living pretty healthy. although weird it is also interesting , my mother tells me that i am my father's daughter, but she also had a boyfriend that she dated possibly at the same time she dated my "father". she tells me who my father is but it's strange because her boyfriend has children, and i am somewhat similar to them. i do and say things that my mothers' boyfriends children do that Nobody else would do. and i have the same birthmark as one of his kids. but what confuses me is that i have a birthmark that my father has also. i also have a difficult time balancing. my legs are misshaped odd. LOL. this actually scares me. and it scares me because what if i was a hermamphordite.

Posted by: Chan on July 4, 2008 3:22 AM

i've always been pretty girlish and boyish at the same time. and have alot of hair on my body that i dislike. so does anybody have any info about these things?????

Posted by: Chan on July 4, 2008 3:24 AM

I think my eldest son is a chimera or mosaic.
MY son is now ten yrs old and like my 4 other boys, is mixed race. All my 5 boys have same mother and father. My eldest son was born with almost half his hair blonde and the other half dark brown. Within a few weeks his eye colour developed and his eye on the blonde side of his head is a quater blue, not brown with blue tints in, i mean a whole quarter of it is blue. His hair is almost devided in a ying yang sign, with the blond hair growing corser and much more of a curl in it than the brown side. The skin under the hair is also differnt in colour tone, the dark brown being more blueish and the blonde side being much pinker. He also has a white patch of skin on his jaw line and one on his leg. All of my other boys have mousey brown hair (although slight difference in colour tone) and brown eyes. None of my other children have blonde hair.I am white and have mousey hair green eyes and their father is mixed race, carabiean/white with brown eyes and dark brown hair. None of our parents have blue eyes or blonde hair naturally apart from my father when he was very young. My son will be ten this year, and although depending on the length of his hair, the patches seem to of grown evenly, and the blue patch in his eye hasn't changed in size or colour.
Can anyone give me any more information as i would like to have my son tested if this is possible.

Posted by: veronica on September 30, 2008 5:50 PM

You could have two blood types, but certain blood types are not compatable with each other. You could have a and o or b and o, but if you had a and b type blood as a chimera, your bodys antibodies would literally tear everything apart...

Posted by: imikai on December 10, 2008 11:46 PM

Thanks for posting these everybody,
I am writing a fictional book about a boy with human chimeras

Posted by: kylee on January 31, 2009 12:32 PM

hi interesting,chimerics happen i believe when
theres many generations of incest,maybe on one parents bloodline,hermaphrodites usually are chimeric,exsplains intersex conditions,just 2 twins fighting 2 live in one body,unusual yes but this is what makes
life interesting all the best to all beautiful unique chimeras

Posted by: wendy on February 3, 2009 2:19 AM

my daugter was born with a faint line going down her face. she has the same color eyes but they seem to keep changing. they were blue but now a brown and blue colors mixed together. she has a brown eyebrow and a blonde eyebrow and a brown eyelash and a blonde eyelash. on the side with the blonde she has blonde hairs going in her hair liek highlights. she is 6 months old and the pediatrican has never seen anything like it before

Posted by: selina smith on March 14, 2009 3:15 PM

Hi, I'm 15 and I think I might be a chimera..my mom doesn't know who my father is because she had different partners at the time..when I was little she had a man DNA tested to see if he was my father but it didn't match his but anyway years later I had my blood tested again for something and got a different DNA then last time..I don't know if they got my test mixed up or I have a twins DNA..also I have a line that goes straight down my belly and my arms and on them one side is shades darker than the other side and smoother than the other side... I'm jus trying to find out what I am cause this could be a possibility..

Posted by: Alexis on April 8, 2009 11:55 PM

I also have identical lines going down the inside back of my legs. Since I saw the TLC show on chimeras, I think I am one. ??? Any ideas?

Posted by: Lisa on May 22, 2009 10:27 AM

Dear Chan, have you checked "congenital Adrenal Hyperplasia"?

Posted by: Laura on June 22, 2009 6:05 PM

I have one ear that is half an inch bigger than the other and is a completely different shape (pointy and sticks out). I have one foot that is 1/2 inch bigger due to mismatched big toes. I have always had odd colouring. I was born with black hair which fell out and grew in pale blond. As I got older my hair darkened to brown except for two patches in the front which stayed light blond. My eyebrows have always been black. My blue eyes have a gold ring around the pupil. I have odd excess bone deposits in my mouth and joint problems. Could I have two sets of DNA?

Posted by: Mermer on July 12, 2009 4:33 PM



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