Chiari type 1 malformation (CM1) occurs in the region where the brain and the spinal cord join. In this disorder, the portion of the brain called the cerebellum and/or brainstem lies lower than usual. Often, a portion of the cerebellum called the cerebellar tonsils protrudes out of the base of the skull into the spinal canal. This protrusion causes pressure in the brain, contributing to the symptoms people experience.

There are many symptoms associated with CM1. These symptoms may include headaches, especially at the base of the skull, dizziness, double vision, weakness in the arms, and/or difficulty walking. When symptoms are present, they are often vague or nonspecific. As a result, the diagnosis of CM1 is often delayed until more severe symptoms present themselves or after milder symptoms persist for some time.

Syringomyelia is a condition characterized by a fluid-filled cyst in the spinal cord. In some instances, syringomyelia is caused by an injury. However, there are also some cases that are present at birth. Often, individuals with CM1 are also diagnosed with syringomyelia.


The Duke Molecular Physiology Institute (DMPI), formerly the Duke Center for Human Genetics, is investigating the hereditary basis of Chiari type I malformation with or without syringomyelia (CM1/S). Our research is aimed at learning if CM1/S is indeed caused by factors inherited through the family and, if so, which genes are involved. The long-term goal is to find out how these genetic factors cause or contribute to CM1/S, with the hope that this knowledge will lead to improved diagnosis and more effective treatments.

Several lines of evidence point to a genetic contribution to CM1/S. This evidence includes families with multiple individuals all diagnosed with CM1/S. Observations of identical twins (genetically the same) have shown that if one twin is diagnosed with CM1/S, the other twin often also has CM1/S. Finally, CM1/S is known to co-occur with a number of different genetic syndromes.

This research has been supported in part by grants from the National Institutes of Health, Bobby Jones Open Fund, American Syringomyelia & Chiari Alliance Project (ASAP), Chiari & Syringomyelia Foundation (CSF) and Conquer Chiari.

DMPI CM1/S Study Team

Allison Ashley-Koch, PhD Co-Principal Investigator and Genetic Epidemiologist
David Enterline, MD Neuroradiologist
Heidi Cope, MS, CGC Genetic Counselor, Study Coordinator


Herbert Fuchs, MD
Neurosurgeon, Duke University Medical Center

Gerald Grant, MD
Neurosurgeon, Stanford University Medical Center

Paolo Bolognese, MD
Neurosurgeon, North Shore University Hospital
Associate Director, The Chiari Institute

Bermans Iskandar, MD
Neurosurgeon, University of Wisconsin Medical School

Ulrich Batzdorf, MD
Neurosurgeon, University of California Los Angeles (UCLA)

John Oro, MD
Neurosurgeon, The Medical Center of Aurora

DMPI Publications on CM1/S

As DMPI researchers and collaborators continue to define the genetic causes of CM1/S, we publish findings in leading academic journals and share knowledge with colleagues at meetings and conferences.

List of CM1/S Research Publications


The DMPI is actively recruiting families who have TWO OR MORE family members with Chiari type 1 malformation, with or without syringomyelia. These family members must be related to each other by blood, and BOTH must be willing to participate.

Study participation involves these steps:

  • Contact the study coordinator.
  • Provide blood samples from family members both with and without CM1.
  • Answer questions about family and medical history.
  • Complete a medical questionnaire.
  • Review of medical records and MRIs to confirm the diagnosis of CM1
  • Potentially ask other degree family members (parents, siblings, children) to participate in the study.

If your family meets these criteria and is willing to participate in the study, please contact the study coordinator.

CM1/S Study Coordinator
Phone: (919) 684-0655


CM Research Newsletters

News About Chiari Research, February 2014

News About Chiari Research, Spring 2012

Support Groups and Information Sources

American Syringomyelia & Chiari Alliance Project (ASAP)
Phone: (toll free) (800) 272-7282
Phone: (903) 236-7079

Chiari & Syringomyelia Foundation (CSF)
Phone: (718) 966-2593

Conquer Chiari

Canadian Syringomyelia Network
Phone: (905) 471-8278