It is characterized by a decrease in the amount of insulating myelin surrounding the nerves (hypomyelination) and belongs to a group of genetic diseases referred to as leukodystrophies.

Other signs may include tremor, lack of coordination, involuntary movements, weakness, unsteady gait, and over time, spasticity in legs and arms.

[citation needed] The disease is one in a group of genetic disorders collectively known as leukodystrophies that affect the growth of the myelin sheath, the fatty covering—which acts as an insulator—on nerve fibers in the central nervous system.

[10] In December 2008, StemCells, Inc received clearance in the United States to conduct a phase I clinical trials of human neural stem cell transplantation.

[12] In 2019 Paul Tesar, a professor at Case Western Reserve University, used CRISPR and antisense therapy in a mouse model of Pelizaeus–Merzbacher with success.

[13][14][15] In 2022 Case Western Reserve University entered an exclusive licensing agreement with Ionis Pharmaceuticals to develop a human treatment for the disorder.