Adult-onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) is a neurological condition characterized by changes to certain areas of the brain. A hallmark of ALSP is leukoencephalopathy, which is the alteration of a type of brain tissue called white matter. White matter consists of nerve fibers (axons) covered by a substance called myelin that insulates and protects them. The axons extend from nerve cells (neurons) and transmit nerve impulses throughout the body. Areas of damage to this brain tissue (white matter lesions) can be seen with magnetic resonance imaging (MRI). Another feature of ALSP is swellings called spheroids in the axons of the brain, which are a sign of axon damage. Also common in ALSP are abnormally pigmented glial cells. Glial cells are specialized brain cells that protect and maintain neurons. Damage to myelin and neurons is thought to contribute to many of the neurological signs and symptoms in people with ALSP.
Symptoms of ALSP usually begin in a person's forties and worsen over time. Personality changes, including depression and a loss of social inhibitions, are among the earliest symptoms of ALSP. Affected individuals may develop memory loss and loss of executive function, which is the ability to plan and implement actions and develop problem-solving strategies. Loss of this function impairs skills such as impulse control, self-monitoring, and focusing attention appropriately. Some people with ALSP have mild seizures, usually only when the condition begins. As ALSP progresses, it causes a severe decline in thinking and reasoning abilities (dementia).
Over time, motor skills are affected, and people with ALSP may have difficulty walking. Many develop a pattern of movement abnormalities known as parkinsonism, which includes unusually slow movement (bradykinesia), involuntary trembling (tremor), and muscle stiffness (rigidity). The pattern of cognitive and motor problems are variable, even among individuals in the same family, although almost all affected individuals ultimately become unable to walk, speak, and care for themselves.
ALSP was previously thought to be two separate conditions, hereditary diffuse leukoencephalopathy with spheroids (HDLS) and familial pigmentary orthochromatic leukodystrophy (POLD), both of which cause very similar white matter damage and cognitive and movement problems. POLD was thought to be distinguished by the presence of pigmented glial cells and an absence of spheroids; however, people with HDLS can have pigmented cells, too, and people with POLD can have spheroids. HDLS and POLD are now considered to be part of the same disease spectrum, which researchers have recommended calling ALSP.
ALSP is thought to be a rare disorder, although the prevalence is unknown. Because it can be mistaken for other disorders with similar symptoms, ALSP may be underdiagnosed.
ALSP is caused by mutations in the CSF1R gene. This gene provides instructions for making a protein called colony stimulating factor 1 receptor (CSF-1 receptor), which is found in the outer membrane of certain types of cells, including glial cells. The CSF-1 receptor triggers signaling pathways that control many important cellular processes, such as cell growth and division (proliferation) and maturation of the cell to take on specific functions (differentiation).
CSF1R gene mutations in ALSP lead to an altered CSF-1 receptor protein that is likely unable to stimulate cell signaling pathways. However, it is unclear how the gene mutations lead to white matter damage or cognitive and movement problems in people with ALSP.
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
In most cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family.
Other Names for This Condition
- hereditary diffuse leukoencephalopathy with axonal spheroids and pigmented glia
Additional Information & Resources
Genetic Testing Information
Genetic and Rare Diseases Information Center
Research Studies from ClinicalTrials.gov
Catalog of Genes and Diseases from OMIM
Scientific Articles on PubMed
- Ali ZS, Van Der Voorn JP, Powers JM. A comparative morphologic analysis of adult onset leukodystrophy with neuroaxonal spheroids and pigmented glia--a role for oxidative damage. J Neuropathol Exp Neurol. 2007 Jul;66(7):660-72. Citation on PubMed
- Freeman SH, Hyman BT, Sims KB, Hedley-Whyte ET, Vossough A, Frosch MP, Schmahmann JD. Adult onset leukodystrophy with neuroaxonal spheroids: clinical, neuroimaging and neuropathologic observations. Brain Pathol. 2009 Jan;19(1):39-47. doi: 10.1111/j.1750-3639.2008.00163.x. Epub 2008 Apr 15. Citation on PubMed or Free article on PubMed Central
- Kleinfeld K, Mobley B, Hedera P, Wegner A, Sriram S, Pawate S. Adult-onset leukoencephalopathy with neuroaxonal spheroids and pigmented glia: report of five cases and a new mutation. J Neurol. 2013 Feb;260(2):558-71. doi: 10.1007/s00415-012-6680-6. Epub 2012 Sep 30. Review. Citation on PubMed
- Mitsui J, Matsukawa T, Ishiura H, Higasa K, Yoshimura J, Saito TL, Ahsan B, Takahashi Y, Goto J, Iwata A, Niimi Y, Riku Y, Goto Y, Mano K, Yoshida M, Morishita S, Tsuji S. CSF1R mutations identified in three families with autosomal dominantly inherited leukoencephalopathy. Am J Med Genet B Neuropsychiatr Genet. 2012 Dec;159B(8):951-7. doi: 10.1002/ajmg.b.32100. Epub 2012 Oct 4. Citation on PubMed
- Nicholson AM, Baker MC, Finch NA, Rutherford NJ, Wider C, Graff-Radford NR, Nelson PT, Clark HB, Wszolek ZK, Dickson DW, Knopman DS, Rademakers R. CSF1R mutations link POLD and HDLS as a single disease entity. Neurology. 2013 Mar 12;80(11):1033-40. doi: 10.1212/WNL.0b013e31828726a7. Epub 2013 Feb 13. Citation on PubMed or Free article on PubMed Central
- Rademakers R, Baker M, Nicholson AM, Rutherford NJ, Finch N, Soto-Ortolaza A, Lash J, Wider C, Wojtas A, DeJesus-Hernandez M, Adamson J, Kouri N, Sundal C, Shuster EA, Aasly J, MacKenzie J, Roeber S, Kretzschmar HA, Boeve BF, Knopman DS, Petersen RC, Cairns NJ, Ghetti B, Spina S, Garbern J, Tselis AC, Uitti R, Das P, Van Gerpen JA, Meschia JF, Levy S, Broderick DF, Graff-Radford N, Ross OA, Miller BB, Swerdlow RH, Dickson DW, Wszolek ZK. Mutations in the colony stimulating factor 1 receptor (CSF1R) gene cause hereditary diffuse leukoencephalopathy with spheroids. Nat Genet. 2011 Dec 25;44(2):200-5. doi: 10.1038/ng.1027. Citation on PubMed or Free article on PubMed Central
- Sundal C, Wszolek ZK. CSF1R-Related Adult-Onset Leukoencephalopathy with Axonal Spheroids and Pigmented Glia. 2012 Aug 30 [updated 2017 Oct 5]. In: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Stephens K, Amemiya A, editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2020. Available from http://www.ncbi.nlm.nih.gov/books/NBK100239/ Citation on PubMed
- Wider C, Van Gerpen JA, DeArmond S, Shuster EA, Dickson DW, Wszolek ZK. Leukoencephalopathy with spheroids (HDLS) and pigmentary leukodystrophy (POLD): a single entity? Neurology. 2009 Jun 2;72(22):1953-9. doi: 10.1212/WNL.0b013e3181a826c0. Review. Citation on PubMed or Free article on PubMed Central