The EGR2 gene provides instructions for making a protein called early growth response 2, which is part of the early growth response family of proteins. These proteins bind to specific areas of DNA and help control the activity of particular genes. On the basis of this action, the proteins are referred to as transcription factors. The early growth response 2 protein activates several genes that are involved in the formation and maintenance of myelin, the fatty substance that covers and protects nerve cells. Myelin promotes the efficient transmission of nerve impulses. If myelin is lost (demyelination) or its structure is disrupted, the transmission of nerve impulses is impaired. Mutations in the EGR2 gene can cause two forms of Charcot-Marie-Tooth disease, type 1D or type 4E (sometimes called congenital hypomyelinating neuropathy) or a severe form of type 1D (sometimes called Dejerine-Sottas syndrome) that begins during infancy or early childhood.