Genetic Analysis of the Chiari I Malformation

The purpose of this study is to better understand the genetic factors related to the Chiari I malformation. In people with this abnormality, the lower part of the skull is smaller than normal. As a result, the lowest part of the brain, called the cerebellar tonsils, protrudes out of the hole at the bottom of the skull into the spinal canal. This study will try to discover the location of the genes responsible for the malformation.

Candidates for this study are: 1) Patients with Chiari I malformation who also have a family member with the abnormality or a family member with syringomyelia (a cyst in the spinal cord that is often associated with the Chiari I malformation). 2) Family members of patients with the Chiari I malformation.

Participants will have a medical history and physical and neurologic examinations. They will undergo magnetic resonance imaging (MRI) of the brain and cervical (neck) spinal cord to measure the size of the head and determine the presence of the Chiari I malformation and syringomyelia. A small blood sample (about 2 tablespoons) will be drawn for DNA studies relating to the Chiari I malformation.

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Key information

Conditions

Syringomyelia Arnold-Chiari Malformation Carbohydrate Metabolism, Inborn Errors Central Nervous System Diseases Congenital Abnormalities Congenital, Hereditary, and Neonatal Diseases and Abnormalities Connective Tissue Diseases Genetic Diseases, Inborn Lysosomal Storage Diseases Metabolic Diseases Metabolism, Inborn Errors Mucinoses Mucopolysaccharidoses Mucopolysaccharidosis IV Nervous System Diseases Nervous System Malformations Neural Tube Defects Nutritional and Metabolic Diseases Skin and Connective Tissue Diseases Spinal Cord Diseases Type I Arnold Chiari Malformation

Age range

1 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Kazan State Medical University, Kazan', Russia

About this study

Objectives: The goal of this study is to establish family pedigrees and undertake genetic linkage analysis that will identify gene loci associated with the Chiari I malformation and underdevelopment of the bone forming the posterior cranial fossa.

Study Population: Patients and family members of patients with the Chiari I malformation. Because the research institutions are located in the United States and Russia, subjects will be recruited predominantly from these countries.

Design: Human subjects will undergo 1) neurologic examinations, 2) head and cervical MRI scans to evaluate for the Chiari I malformation, syringomyelia, and maldevelopment of the posterior fossa, and 3) isolation and analysis of genomic DNA from whole blood for linkage analysis.

Outcome Measures: Pedigrees will be established based on the MRI findings. The Chiari I phenotype will be defined as the caudal portion of the cerebellar tonsils lying greater than or equal to 2 mm below the foramen magnum and underdevelopment of the bone of the posterior fossa will be defined as 1) obliteration of the CSF pathways in the inferior portion of the posterior fossa, 2) posterior fossa volume to supratentorial volume ratio of less than or equal to 15%, or 3) abnormal shortening of the bones of the skull base. Genetic analysis of the genomic DNA will be performed with DNA polymorphic markers to identify chromosomal loci linked to the small posterior fossa phenotype. A lod score of 3.0 (equivalent to 1000:1 odds in favor of linkage) will be taken as proof that the Chiari I gene maps to the same genetic region of the human genome as a given DNA marker.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

INCLUSION CRITERIA:

To be eligible for entry into the study, a candidate must meet the following criteria:

Patient with a confirmed diagnosis of Chiari I malformation who has a family member with syringomyelia or Chiari I malformation, or

Family member of a patient with a confirmed diagnosis of Chiari I malformation, AND

There are at least two family members diagnosed with Chiari I malformation.

If an adult, able to give informed consent; if a minor, has an adult who is legally responsible for the subject and who is able to give consent.

Exclusion criteria

A candidate will be excluded if he/she:

Has a contraindication to MRI scanning.

Is unable to comprehend the risks of the testing.

Is less than one year of age.

Cannot undergo MRI scanning without sedation.

Treatment and study plan

Primary outcomes

Family Pedigree/Genetic Linkage

Time frame: ongoing

Establish family pedigrees and undertake genetic linkage analysis that will identify gene loci associated with the Chiari I malformation andunderdevelopment of the bone forming the posterior cranial fossa.
Genetic Analysis

Time frame: Genetic Analysis ongoing

Genetic analysis of the genomic DNA will be performed with DNA polymorphic markers to identify chromosomal loci linked to the Chiari I and small posterior fossa phenotype.

Sponsors and collaborators

Lead sponsor

National Institute of Neurological Disorders and Stroke (NINDS)

Nih

Registry information

Important dates

Study start: 2001
First posted: Feb 28, 2000
Registry last updated: Jul 16, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

Completed