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KD diagonostic
Picture of danwolfe
Location: Lewis Center OH
Registered: 05-02-2007
Posts: 5
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I have been learning more about KD and it is pretty fascinating to see the progress on research however I try to be realistic on my situation. My current situation is kind of different why I am sort of reaching out. Although I don’t know, here may not be the place for this kind of discussion. Also I am sorry I missed Dr. Diane Merry who is well known for her work on KD. The time difference is really a killer from Pacific time to Seoul although I will be coming for a month visit to Seattle shortly.

I went to neurologist here in Korea where I live because of advanced progression of sensory polyneuropathy (PN) - meaning almost complete loss of surface and deep sensation in the feet now spreading radiating upward in legs. Otherwise my health is very ok. Neurologist was tuned into KD (first time I heard of it) and first test of genescan CAG repeats was 40 positive. At that time electrodiagnostic (EDX) indicated sensory axonal based polyneuropathy. No other signifiant KD symptoms such as proximal + bulbar weakening, serum CK, signs of androgen insensitivity (AI). This physician sort of wanted to quit then. Second hospital for second opinion about 2 months to repeat all tests - genescan CAG repeat and another round of EDX. Seems like the sensory component is even worse now - no deep or surface sensation in the feet. Nothing on the other KD muscle and AI or serum CK. The genescan CAG repeat is 45....

So Question 1 I am wondering if anyone is familiar with accuracy of the genescan test and rapid change of CAG repeat. If this is kind of rapid onset after just reaching age of 60, I would kind of like to know what to expect. I thought that the testing was pretty well developed and automated using capillary electrophoresis and very reproducible.

Question 2 Second question anyone seen this kind of severe progression of the sensory component in the absence of motor deficit? Most of the clinical studies talk about EDX showing some kind of mild sensory loss during or following motor neuron degeneration even in the absence of the patient showing loss of tactile (sense of touch) sensory function.
Picture of Bruce
Registered: 09-28-2005
Posts: 654
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I asked Dr. Taylor from the University of Pennsylvania to respond to your questions. His comments are below: (Please remember that Dr. Taylor has not seen you as a patient or seen your medical charts. All comments are general in nature and need to be reviewed with your physician)

"First, as to the genetic test result. The KD genetic test is based on PCR
amplification and is very reliable, although I have heard anecdotal reports of
errors. I don't know of any study of the error rate, but I expect it is very
low. Variability (as opposed to error) can result from several things both
biological and technical that I will no go into in detail because it is not
likely relevant here. In this man the CAG repeat size was in the pathogical
range (>38) in both cases and would be considered "positive". Presumably these
tests were done at a reputable lab. I am curious as to how the neurologist
was "tuned in" to KD" and whether there might have been some subclinical signs
on the exam. If uncertainty remains, and he wants to be retested, here is a
list of good labs:


As for sensory neuropathy, this is a very common feature of KD -- typically
a "large fiber sensory axonopathy" which means difficulty predominantly with
vibration sensation, joint position sense, and to some extent light touch. In
many patients (perhaps most), the sensory loss is minor and they are not
bothered or not even aware of this. So the sensory loss in this man is somewhat
unusual in it's severity, though still quite possibly related to KD given his
genetic test results. Another possibility is that there is a second problem
going on leading to sensory neuropathy and (this is the important point) this
should be looked into because treatment may be available.

In particular,
diabetes is more frequent in individuals with KD. Left untreated, diabetes can
lead to a progressive sensory neuropathy among other problems with the eyes and
kidneys. The electrophysioloical characteristics are somewhat different,
usually a "small fiber neuropathy", but there is enough overlap in symptoms and
EP findings (and missing details here) to make this a possibility."
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