This article describes the myelin sheath as “made of protein.” However, Merriam-Webster’s Collegiate Dictionary (online) provides the following definition of myelin: “a soft white somewhat fatty material …” (emphasis added).

Ann M. Throckmorton
La Mesa, Calif.

That’s right. There was an oversimplification in the story. Myelin is made up mostly of lipids .–D. Christensen

From the Nature Index

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