Sticky Blood-Hughes Syndrome Support
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What is the difference between APS & protein C deficiency ?

I have the disfortune of an inquisitive mind..........or is it a disfortune ?

If i get answer's i shall have learnt something today and that will be an achievement.

My daughter in law had a DVT due to a protein C deficiency so now she is on warfarin.

I have Aps so now i'm on blood thinners, i cant help wonder what is the difference between the two illnesses as both illnesses can create clots.

In other words is APS due to a protein deficiency ? She is also curious to know what the difference is between her illness and mine. Jillymo

10 Replies

Hi, this is complicated, but a simple answer is that APS creates clots where clots should not be by attacking and destroying healthy tissue.

Protein C deficiency and Prothrombin A20210Allele mutation (a deformed Prothrombin gene) act in similar ways to each other by increasing the risk of clotting as they are used by the clotting cascade as a sort of control, used to speed up or slow down any clot forming. With both these (or either one) we end up with a deficiency of Activated Protein C (aPC), which is the Prothrombin and Protein C bonded together, which would normally control the speed, so if you have APS and either of these other problems the APS creates a risk of clotting and the other two increase the risks of those clots.

I think that is a very simplified answer, but the best I can remember.




Hi Jillymo,

Protein C is a vitamin K-dependent glycoprotein that is synthesised in the liver. It circulates in an inactive form. It is activated by the thrombin-thrombomodulin complex on endothelial cells. Activated protein C degrades the activated clotting factors Va and VIIIa. The actions of protein C are enhanced by the cofactor, protein S. Protein C also has anti-inflammatory and cytoprotective properties.

The exact mechanism of antiphospholipid syndrome is still being researched but it is thought that antiphospholipid antibodies reduce the levels of annexin V, a protein that binds phospholipids and has potent clot-blocking (anticoagulant) activity. The reduction of annexin V levels is thought to be a possible mechanism underlying the increased tendency of blood to clot and the tendancy to miscarry characteristic of APS.

I'm really sorry that's quite a lot of technical blurb but it basically comes down to biochemistry. Different proteins and antibodies in our blood that, when increased or reduced, can have the same or similar effect in different people.

My grandmother has factor V leiden, which they thought might have caused my problems. It turned out that although factor V leiden is indeed hereditary, I don't have it and have another flavour of clotting issue (APS) instead.

Hope that helps a little!



Hmmm trust me to ask such a complicated question.

Let's put it this way JoJo, i got the bit towards the end then you went and complicated it by throwing the V leiden in. :-) I shall look that one up as i have never heard of APS hereditary ?

Some peoples knowledge on here is quite outstanding, so tell me do both Aps and this factor V leiden have low levels of Annexin gentle with what you reply i still have my L plates on, technical blurp i cant even pronounce the words let alone understand them. :-(

I am told once i am.......wait for it.........anti coagulated or something that sounded like that my head will be able to take more on's hoping. Jillymo x


I'm still waiting to get to the 'well anti-coagulated' point of my brain clearing enough to hold on to much data. I'm just quite lucky that I was pretty scientifically minded before this all really hit me!

Factor V Leiden is a point mutation in the gene for clotting factor V rather than a high or low protein or antibody count. It's a genetic mutation.

There is still a lot of research being done into the whys and wherefores of APS. There are a lot of questions that haven't been definitively answered yet. There is a strong indication of a genetic link, certainly there are a lot of families on the forum with multiple people affected. From what I've observed it's primarily mothers and children that 'share' the syndrome but that is only my casual observation of forum threads and absolutely not based on any kind of scientific research!

I hope that answers your questions without raising too many more! That said there is probably someone on here far better informed that I who may chip in and help out :)


Bless you for all the info, it sounds as if your well on your way to better health.

Take care x


There are plenty of books for sale on the Charity website, they are a good read, the ones by Professor Hughes are great, as are the ones written from a patient perspective. MaryF


I purchased a book from ebay but it was hard reading to say the least.

I will invest in Prof Hughes book. Jillymo


Hughes/APS is not supposed to be hereditary however some families seem to have a close inherited pattern. Mine is like this, two sisters, also probably my brother, my late father, my children, and also on the same side of the family similar incidents occurring with young distant cousins! MaryF


I come from a rather split family so i cant comment on close relatives. My son has the genetic type of hypoparathyroidism so he takes after me

I shall ask the consultant to check his blood, it is best to rule it out than to leave it to fate. Thanks Mary


Very good Jo Jo-------my numbers were thought to be unreal but you can't be tested while on warfarin-- so while having my surgery and was bridging with lov-nox they kept me on lov for 7 weeks with extra monitoring to be able to accurately test the S and C

They did find in my case at that time i was not nearly as off as they thought from the tests taken while i was on the warf. pre-op.

Thanks JO ------ C & J


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