CLL Support Association
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13q deletion - what is it?

I wonder if anyone can help. My recent bone marrow aspiration and biopsy indicated 13 q deletion and P53 unmutated. I asked my consultant what this meant and he helpfully said that the unmutation was a good sign and that, oddly, the 13q deletion seemed to be a good factor in terms of prognosis.

There seems to be little on the internet that explains in layman's terms what the 13q deletion is and what the consequences might be for those of us with CLL. There is a lot more available when it is connected with different childhood diseases or abnormalities.

I understand that 13 q deletion means that a part of my DNA - a chromosome - has been deleted and that this been 'acquired' as a result of my CLL.

Does anyone know what the consequences might be, and whether I should be doing anything to mitigate the effects, if any?

5 Replies

Graham, someone much cleverer than myself on the science of CLL will surely be along to explain the complexities to you but in the meantime you may find the following articles useful in aiding your understanding. The first one from Cheya Venkat is a little dated so don't get spooked by some of the survival rate figures. Treatments have developed and things have moved on since this time. Nevertheless the underlying explanations are very useful;

The second article by Dr. Sharman explains the difference between 'mutated and unmutated'. You will see that the information your Consultant gave you on on your unmutated status being favourable is puzzling but in terms of the 'risk bucket', dependent on other factors, 13q deletion is generally seen as a 'favourable' one.

Also you'll find the related article section to the right has information that you may find useful;

Hope they help. In terms of mitigating the effects, apart from keeping as well as possible, I honestly know of no lifestyle strategy that impacts on our unique genetic profile but I'd love to be proven wrong.

Best wishes,


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Dear NewDawn. Thanks ever so much. I've had a glance at these, but will study them in much more detail when I'm at my desktop. They look very helpful indeed - im grateful to you for digging them out. Best wishes. Graham


Hi Graham,

Further to Newdawn's reply, below I've referenced two more articles from Chaya Venkat. Again, these are several years old, but still provide useful, relevant information, with Terry Hamblin's take on prognostic testing particularly so. The most important thing to bear in mind when you begin reading these articles is that they are only useful as background guides to individuals - they are only really powerful when used to look at populations of CLL patients. To explain that more, if you look at the basic FISH testing covered in these references, that test looks for just four chromosomal abnormalities and if they aren't found, you are told you have a 'Normal' result. The 'Normal' is a misnomer, and really should be 'Unknown'. What we are finding out as research continues (with Dr Sharman's article an excellent recent contribution on what it means to us), is that we are continually discovering new chromosomal abnormalities that together with the already known ones, are increasingly explaining why someone with poor markers may in fact do better than someone with good markers and vice versa.

Where are we with prognostic markers today? By Dr. Terry Hamblin (June 2010)

Does the Percentage of 13q deletion matter?

For the latter article, you need to bear in mind that often it's not a clear measurement of the absence or presence of some of these prognostic markers. There's an arbitrary cut off, based on research, where less than a set percentage is deemed 'negative' and more 'positive'. Further, some of these markers can shift over time as CLL progresses, particularly under the influence of chemotherapy treatment.

It's best not to dwell too much on these prognostic tests; they can be useful in determining what treatments will work best (particularly the chemotherapy treatments), but that's about as far as it goes with regard to 'mitigating the effects'.



I agree with Neil... don't dwell on this stuff, in fact there are many other things at play. If you want to be proactive, eat well, loose weight and exercise...get healthy.

FISH prognosis is clinically relevant, but less so today than a few years ago... new markers , sub clones and new treatments are lessening its importance...


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Many thanks for all the replies, which have been very helpful in understanding this slightly mysterious condition.


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