ALSP: adult-onset leukoencephalopathy with axonal spheroids and pigmented glia; ALSP was formerly known as two different disorders, pigmentary orthochromatic leukodystrophy (POLD) and hereditary diffuse leukoencephalopathy with spheroids (HDLS)

Autosomal dominant: a pattern of inheritance where a person has one normal and one mutated copy of a gene

Axonal spheroids: swelling within part of a neuron that transmits signals; usually found with a loss of myelin

Chromosome: a long piece of DNA that carries genetic material called genes

CSF1R: colony-stimulating factor 1 receptor

CT: computed tomography combines multiple x-rays to produce a more complete image of the body

Gene: part of a chromosome that carries enough DNA to make a specific characteristic of a person

Glia: supportive cells in the nervous system

HSCT: hematopoietic stem cell therapy; a type of bone marrow transplant that uses donor stem cells to replace damaged or mutated stem cells

Leukodystrophy: rare, progressive, metabolic, genetic diseases that affect the brain, spinal cord and nerves that are caused by genetic mutations that lead to loss of myelin

Leukoencephalopathy: a type of leukodystrophy that mainly affects the brain and spinal cord

MRI: magnetic resonance imaging uses magnetic fields and radio waves to produce images of the body

Macrophage: a large white blood cell of the immune system that attacks foreign things in the body

Microglia: a type of glia cell that acts like a macrophage in the brain

Multiple sclerosis: a nervous system disease that affects the brain and spinal cord, and that damages myelin

Mutation: a change in the structure of a gene that may change the way the gene functions or what it makes

Myelin: insulating sheath around nerve fibers that help speed up neuron signals

Neurons: cells in the brain, spinal cord, and nerves that are responsible for transmitting signals from one part of the body to another

Parkinsonian tremor: an involuntary tremor that happens at rest but lessens during sleep or activity