HIBM Cause and Potential Treatments

GNE's official name is "glucosamine (UDP-N-acetyl)-2-epimerase/N-acetylmannosamine kinase." The Gne gene is called a "bi-functional" enzyme which gives instructions to make an enzyme in the body. This enzyme sends messages between cells and tissues to carry out certain functions.

Included in one of this enzyme functions, after it has gone through some chemical changes is to make sialic acid. Sialic acid is a simple sugar which is needed by  the muscles to function normally. In HIBM, a kind of dysfunction/defect happens in the pathway whereby adequate amount of sialic acid is not available for the muslces and cells.

At a point in this production cycle we get a substance (substrate) called ManNAc which is changed to to ManNAc-6 (this means a phosphate molecule is added), later along this cycle it then changes to sialic acid.  Because there is less sialic acid available for the muscles they get weaker and we get HIBM.

Some potential treatments for HIBM which have been published and are being  experimented by scientists and researchers are Sialic acid and ManNAc.  It is believed that some of these may stop the progression of the muscle breakdown and restore some functionality to the muscles. (It is still a debate as to whether all the muscles will regain  the strength). 

Some other forms of treatments are being explored such as gene based therapy which is still in it's "early" stage of development  and may have the answer for a cure for HIBM. In addition, Intravenous Immuno Globulin or IVIG has been tried with a small sample of HIBM patients.  http://hibm.org/arm/_media/about_arm:2010-04.pdf  http://clinicaltrials.gov/ct2/show/NCT00195637?term=hibm&rank=5

Currently, there are two entities working on the "substrate" part of  clinical trials.  Ultragenyx a biopharma company is working on Sialic Acid Extended Release in a tablet form.  They have finished  phase one and  is starting phase 2 trial at three different sites in the U.S.A. and one site in Israel.   http://clinicaltrials.gov/ct2/show/NCT01517880?term=hibm&rank=4

The National Institutes of Health in Bethedsa is doing a "Natural History" study where they are gathering information to measure and understand the progression with HIBM.  Most likely, they may start a trial with ManNAc later this year.   http://clinicaltrials.gov/ct2/show/NCT01417533?term=HIBM&rank=2

Personal Note:
As a person who has HIBM, I have become increasingly aware of how extensive research has to delve into a disease in order to come up with experimental "mouse"models to test a particular medicine on.  This process takes years, dedication on the part of the researchers, and enormous amount of money for a treatment/medicine to get to the market.  Hence, it is such a  precious gift to me  that Ultragenyx, NIH, and HRG/ARM have put so much work into studying HIBM and attempting to speed up treatment(s) for HIBM.

References:
http://wiki.medpedia.com/Glucosamine_(UDP-N-acetyl)-2-epimerase/N-acetylmannosamine_kinase_(GNE)
http://ghr.nlm.nih.gov/gene/GNE
http://www.jci.org/articles/view/30954/files/pdf
http://clinicaltrials.gov/ct2/show/NCT00195637?term=hibm&rank=5
http://www.bdipharma.com/Clinical-What-is-IVIG.aspx