Diploid Cytogenetics

[Greg H]

Hi All!

I was playing around with MD Anderson's alternative to IPSS (which is actually pretty informative for low risk folks) and ran across a term for which I can't seem to find a good definition: "diploid cytogenetics."

This was used to describe a particular chromosomal abnormality in MDS patients in this sentence: "In this analysis, diploid and 5q only were favorable cytogenetic, all others were considered as unfavorable cytogenetics."

Googling got me some references to diploid cytogenetics in AML, but no definition. I know the term can be used to refer to the full complement of chromosomes when the cell is in the midst of dividing and we humans have 46 instead of 23, but I'm not sure what it means outside that context. Surely there aren't MDSers walking around constantly with two full sets of chromosomes in their progenitor cells.

Maybe it refers to a situation where folks have two copies of one chromosome; I'm not sure. But I thought maybe one of you has this or at least knows what it means.

Happy Independence Day to the Yanks amongst us, Happy Belated Canada Day to our friends North of the Border, with apologies to you English and best wishes to the Manx rocket Mark Cavendish as The Tour de France gets underway today.

Take care!

Greg

[tytd]

Hi Greg,
Hope you are doing well. I believe diploid cytogenetics just refers to the normal situation. If your cells have the normal karyotype with one chromosome from each parent then you have the normal (diploid = two) number. If you get a copy of a karyotype done from a normal male bone marrow you would see 2 copies of the 22 chromosomes and one X and one Y for the sex chromosomes. (a normal karyotype or normal diploid cytogenetics). However, in your case, you have some cells with abnormal cytogenetics with trisomy 8 which means you would have 3 copies of the number 8 chromosome instead of the normal 2. I am sure you probably already figured this out. By the way, where is the Manx rocket from? Good Luck tytd

[Greg H]

Hey tytd!

Thanks for that explanation, which makes perfect sense. It would be just like a bunch of hematologists to decide to use something complicated, like "diploid cytogenetics," to mean "normal."

The Manx rocket -- which, it occurs to me, may be called "the Manx Missile," since that has a better alliterative effect -- is from the Isle of Man, which sits in the Irish Sea between England and Ireland. "The Cav," as he is also known, is a classically mouthy, egotistical sprinter (and a charming and attractive young man, according to my wife) who added much to the fun of last year's Tour de France. I enjoy watching the saga that is the Tour each year -- despite all the melodrama of the doping scandals -- at least as much for the colorful characters and fantastic scenery as for the sport. Plus, I learn stuff. Who knew folks from the Isle of Man were called Manx?!

By the way, back to cytogenetics, when I got the results of my last BMB, the cytogenetic report included an actual photo of my chromosomes. It was kind of odd to look at that -- particularly with those three copies of Chromosome 8 staring you in the face. Unfortunately, it was just a fax and not suitable for framing, but I hope to wrangle a better out of the NIH so I can hang it on my wall.

Take care!

Greg

[BerryP]

I have SAA/Hypo MDS with bone marrow cellularity of 15% and have been told I have a trisomy 15. While I understand this means a third copy of chromosome 15 I have no idea what it means with relevance to my condition. I have blood tx every four weeks and as ATG failed they are just giving me ciclosporin and seeing how I do. I actually feel quite well at the moment courtesy of extra blood to put hemoglobin over 10 and it was the good stuff this time! Can echo diploid meaning two copies. If anyone out there knows anything about this stuff would be most happy to hear. Berry

[Neil Cuadra]

Greg,

I too think that diploid refers to having a pair of each chromosome in the cell. In other words, being normal, as opposed to having monosomies or trisomies. Being any of the three can be predictive.

I've also run across the words tetraploid, polyploid, and hyperdiploid.