Ribose-5-phosphate Isomerase Deficiency and Ribose Risks

Here's an interesting article on a genetic disorder producing deficient activity of ribose-5-phosphate isomerase, one of the enzymes of the nonoxidative pentose cycle (an enzyme whose activity bridges the nonoxidative and oxidative pentose cycles):

http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=14988808

The authors talk about hyperosmotic stress, due to the accumulation of ribitol and other "polyol" sugar alcohols, potentially being responsible for the leukoencephalopathy (damage to the white matter, to the myelin and the cells associated with it). This is interesting, given that glycerol is known to be an osmolyte and was once used to treat cerebral edema. This type of osmotic effect of sugar alcohols tends to be really damaging in the long term. Ribitol and other polyols could conceivably build up in a normal person who took exogenous ribose. It probably wouldn't happen at reasonable doses, and neurological damage has never been reported in response to ribose (even in people with neurological symptoms). Ribose actually helped reduce seizures in one person with "myoadenylate deaminase deficiency" (the cause underlying this group of disorders is unknown, hence the quotation marks), but it's worth being aware of all the potential issues.