Calcium Channel N Type Antibody Question Please

[Raisin]

My new neurologist ran a paraneoplastic panel. Everything was 0 except Calcium Channel Type N antibodies showed up but were at the top of the normal range. I am wondering why they would show up at all and should I just "let it go" because they are in the normal range or should I advocate for future retesting to make sure they stay in the normal range? I am not freaking out about it. It just peaks my curiosity because so far all "causes" seem to remain a mystery in my case. Thank you for being there everyone!

[Natops]

Well…. There’s a few of us on this forum that have N-type AB and we are all kind of bewildered and confused on dealing with what it means. Obviously I don’t know what to tell you about your “top of normal range”. Mine was considered high (2012) - 0.38 H nmol/L <=0.03 and (2013) 0.45 H nmol/L <=0.03.

This is a paraneoplastic antibody. . N-type AB has a high association with cancer (Small Cell Lung Cancer) – so… I would think that would be worth rechecking. I found a medical journal from Mayo on the statistical frequency of paraneoplastic antibodies – as far as N-type goes:

http://clincancerres.aacrjournals.org/content/early/2014/05/14/1078-0432.CCR-14-0652.full.pdf+html

It discusses the likelihood of specific autoantibodies to coexist. What autoantibodies cluster in reality vs hypothesized by chance which is kind of confusing to me on how they formulated their hypothesized values.

Of the 78,889 patients tested, 9,183 (12%) had one or more neural autoantibodies: 7,592

(83%) had only one, 1,316 (14% ) had two, 213 (2.3%) had three, 52 (0.57%) had four, 9 (0.1%)

had five and 1 (0.01%) had six. These observed frequencies exceed the frequencies hypothesized

if clustering of autoantibodies occurred only by chance: 1,316 patients were observed with 2

neural autoantibodies, compared with 365 expected by chance; 213 patients were observed with

3 neural autoantibodies, compared with 10 expected by chance ; 62 patients were observed four

or more autoantibodies, compared with 0 expected by chance

The bottom line that I gathered from it as far as N-type Antibody:

Out of that 78,889 889 patients (1.13%) had N-type Antibody.

Out of that 889 patients 233 of them also tested positive for P/Q. (the most frequent co-existing AB)

Out of those 889 patients 74 of them tested positive for VGKC (Potassium) antibody (the second most frequent co-existing AB)

Out of those 889 patients 64 of them tested positive for striational AB. (the third most)

As the Mayo clinic experts told me…. They are the subject matter experts on this antibody and they have more questions than answers in discussing it with me. There’s much they don’t know. The specialist told me this antibody is known as a “tag along” antibody…. It’s usually found with other antibodies – as stated above P/q is the most common and that is primarily found in Lambert Eaton Disease. I can’t locate an additional antibody…. It seems (so far) I have just N-type alone.

Dysautonomia is a symptom of paraneoplastic antibodies. What are your symptoms? I have muscular pain throughout my body and I have POTS. I also have weakness. I think the take away is the association with cancer. A positive hit on a para antibody is complete justification for a CT scan

[Raisin]

Thanks Natops! That is great information. And you're right. It seems that when it comes to antibodies, there can be alot of bewilderment. I don't seem to have any other antibodies showing themselves either so if they are " tagging along" , then they haven't told us what they are tagging along with and I think I have had every test known to mankind at this point. I don't have my follow up for a few months but your information will help me to ask the right questions. Symptom wise, I have Pots, hypovolemia, major blood pooling, small blood cell mass (?) , dizziness and weakness with leg ataxia after I am upright for awhile and two new things which are fatigue and joint pain in my hands and toes. I also have sicca symptoms so I am getting a lip biopsy for Sjogren's in Sept. I also have major abdominal pain but I attribute that to endometriosis or bowel issues. I am like everyone else here, full of fun! Thanks thanks thanks for your knowledge!

[Psalm 23]

Hi Raisin,

I'm sorry you are having to deal with this antibody issue as well. I tested positive for the calcium channel n-type antibody this past spring. I had previously tested negative so it came as a complete surprise to my Neuro and myself. Because of the cancer connection as was pointed out by Natops at the very least you should be retested at a later date. I was advised to have a CT of the chest, abdomen and pelvis as well as a mammogram and gyn exam. I am also scheduled for a repeat paraneoplastic panal next month. I was told by my hematologist/oncologist that if there was no cancer detected after 2 years then the likelihood of it developing was very slim. My Neuro said the presence of this antibody was unexpected and is of unclear significance and that this antibody can be a marker of an autoimmune process or sometimes can be a marker that there is a small cancer hiding out somewhere. Many unknowns here. I'm glad you have follow up.

Janet

[Raisin]

Thank you Psalm. I am sorry to hear what you and Natop have to contend with. I am glad that there are good people following up with you.

It's weird, I have always felt like there is something hiding in my body and that if I am just patient , (which I am not lol) , it will show itself and then everyone will see it plain as day. Maybe alot of pots patients feel this way. I know that everything happens at the right time . I would be agreeable to a cat scan as I have bad abdominal pain anyway. Last time I had this type of pain, there was air in the lining of my intestines. They didn't know where that came from. Well, May God Bless us all!

[Psalm 23]

Thank you Raisin. It can unfortunately be a long road trying to get answers and help. It really is all about seeking out the experts in the field. It wasn't until I finally realized who I needed to see that many of the pieces began to fall into place. Except for this odd antibody that turned up I have finally been given diagnoses that make sense and medications that help. I hope you make progress on your journey. I'm so sorry about your abdominal pain. That definitely needs follow up.

Yes. God bless us all.

Janet

[Jon6945]

Raisan,
Sorry to hear your dealing with these symptoms and the dreaded N-Type. As Natops and Psalm suggested it would be good to do some CAT scans, being that this antibody can be associated with cancers. If the scans are clean then it is probably suggestive of some underlying autoimmune processs. I know this antibody is often seen in Autonomic Neuropathy and Lambert Eaton. Can interfere with the release of acetylcholine at the neuromuscular junction causing weakness. Or the symptoms could manifest slightly different for you. Doesn't have to fall neatly into one of those diagnosises. But it is good your level is not really out of range.

I've tested positive for the N-Type too but over the range and also have GAD65 antibodies and GD1a antibodies. Diagnosed with acute axonal motor neuropahty, Stiff Person Syndrome and Autonomic Neuropathy. I am a disaster. Used to be a completely healthy, young, athletic, working, dating, normal etc. and then one day all these antibodies and things went completely haywire. In any case sorry to hear about the abdomial pains and other symptoms. Hope you get some answers and find some treatment to help. Keep us posted with everything.

[Raisin]

Jon6945, that is very interesting what you said about autonomic neuropathy as that is what the neurologist mentioned when he saw me. I thought he meant small fiber neuropathy and I told him my skin biopsy was fine but he explained how it is the autonomic fibers that are messed up. But, he did not add that as a diagnosis as far as I know. I will see him again and now I feel good about having some more intelligent questions to ask. I have said before that I used to pride myself on my ability to learn and understand these things but now I can't seem to grasp as much anymore. I remember in college taking a psychopharmacology class and aceing it. Now, I can't even remember which is sympathetic and which is parasympathetic. Lol!

Sorry to hear about your mess going on! We are all a bit of a mess, eh? God bless.

[diabeticgonewild]

Rasin,

I have AAG (ganglionic nicotinic acetylcholine receptor antibody positive).

I know somebody whose AAG antibodies would go from the high end of normal, and then upon being retested, would be slightly abnormal. The single abnormal test prompted IVIg treatment.

At the very minimum, you need scans for cancer and retests for this panel every few months.

[Raisin]

Thank you diabeticgonewild. (love the name by the way). I will definitely ask when I see the neurologist the next time. I seem to be on the "see you in 3 months" wheel with all the docs so it will be a little bit but I do feel I need to advocate for retesting at some point as I feel it is better to be safe than sorry. Thank you for your wisdom.

[diabeticgonewild]

You are very welcome Rasin. Good luck!

[freewill45]

I as well have been diagnose with a positive N-type antibody. I had the test done twice and came back positive both times. My Neuro did EMG checking for Lambert eaton he says they were negative .So he schedule a ct of the chest. Turns out a 6mm nodule was found in the right lower lobe of the lung.  Pulmonolist wont say its cancer till he sees if it grows. So now its the waiting game. 

[Pistol]

@freewill45 - I too recently had a CT scan and they found a nodule in my pleural space ( not the usual lung nodule ). I also have to wait 6 months ( October ) until they will recheck the CT. Just be positive and hang in there!!!!

[freewill45]

Pistol thanks , I am content with whatever is ahead.  I get another ct in 3 months, then 6 months.  You hang in there too!!