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Disease Profile

Hypertrophic olivary degeneration

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)



Hypertrophic olivary degeneration (HOD) is a rare neurological condition caused by degeneration in the brain stem, the structure that connects the brain to the spinal cord.[1] Signs and symptoms include palatal tremors, lack of movement coordination (ataxia), Holmes tremor, vision problems, muscle weakness, and gait impairment, along with an MRI showing enlargement (hypertrophy) of the inferior olivary nucleus. The inferior olivary nucleus is the lower part of the olivary body, an oval structure located on each side of the brain stem that assists in cerebellar motor learning and functioning.[2][3][4] HOD is considered unique because the olive initially becomes hypertrophic rather than atrophic (wasted). Over time, the olive goes through atrophy. These changes can be followed by MRI, and even though the imaging characteristics of HOD resolve, the clinical hallmarks such as palatal tremor persist.[1] HOD is caused by lesions to the dentate-rubro-olivary pathway (or Guillian-Mollaret triangle). Lesions may be due to bleeding, ischemia (restricted blood flow), vascular malformations, infarct (localized tissue death), tumors, and several neurological diseases, but there are cases of HOD where no cause can be identified. HOD may be classified as unilateral (affecting one side) or bilateral (affecting two sides). The condition is commonly managed with medication, but some cases may require surgery.[2][4]

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • PubMed is a searchable database of medical literature and lists journal articles that discuss Hypertrophic olivary degeneration. Click on the link to view a sample search on this topic.


  1. Sanverdi SE, Oguz KK & Haliloglu G. Hypertrophic olivary degeneration in children: four new cases and a review of the literature with an emphasis on the MRI findings. The British Journal of Radiology. 2012; 85(1013):511-516. https://www.birpublications.org/doi/full/10.1259/bjr/60727602.
  2. Sabat S, Mannering N & Agarwal A. Hypertrophic olivary degeneration: Case series and review of literature.. J Neurol Sci. November 15, 2016; 370:180-186. https://www.ncbi.nlm.nih.gov/pubmed/27772756.
  3. Cosentino C & cols.. Bilateral Hypertrophic Olivary Degeneration and Holmes Tremor without Palatal Tremor: An Unusual Association. Louis ED, ed. Tremor and Other Hyperkinetic Movements. 2016; 6:400. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4954943/.
  4. Konno T, Broderick DF, Tacik P, Caviness JN & Wszolek ZK. Hypertrophic olivary degeneration: A clinico-radiologic study. Parkinsonism Relat Disord. July, 2016; 28:36-40. https://www.sciencedirect.com/science/article/pii/S1353802016300876.
  5. Carvalho CH, Kimmig H, Lopez WO, Lange M & Oeckler R. Hypertrophic Olivary Degeneration: A Neurosurgical Point of View. J Neurol Surg A Cent Eur Neurosurg. January, 2016; 77(1):59-62. https://www.ncbi.nlm.nih.gov/pubmed/26588253.