Yes, it can be confusing, but don't be confused as they are the same thing. Grierson Gopalan syndrome is just the older name for the problem of burning feet that is not used as much these days. The trend in the last decade or so is to avoid naming disease and conditions after people.

Some neurologists still use the term Grierson Gopalan syndrome when the cause of the burning feet is not known. A lot of cases of burning feet have an identifiable cause (eg a deficiency or diabetes) and tend not to get called Grierson Gopalan
See:
https://burningfeetblog.com/grierson-gopalan-syndrome/
https://podiatryfaq.com/knowledge-base/what-is-grierson-gopalan-syndrome/
https://podiapaedia.org/wiki/neurology/burning-feet/grierson-gopalan-syndrome/