This domain family is found in eukaryotes, and is approximately 220 amino acids in length. The family is found in association with pfam02141, pfam03456, pfam03455. This family is the middle region of SBF2, a member of the myotubularin family. Myotubularin-related proteins have been suggested to work in phosphoinositide-mediated signalling events that may also convey control of myelination. Mutations of SBF2 are implicated in Charcot-Marie-Tooth disease.