Clinical Trial: A Study of the Genetic Analysis of Brain Disorders

Study Status: Recruiting
Recruit Status: Recruiting
Study Type: Observational

Official Title: Genetic Analysis of Brain Disorders

Brief Summary: A study of the complex genetics of brain development will be undertaken with an emphasis on those genes that cause the most common structural brain anomaly in humans called holoprosencephaly (HPE). This malformation of the brain can result from either environmental or genetic causes, and it is the aim of these investigations to determine the genes responsible for both normal and abnormal brain development through the study of patients with this disorder. Mutations in one such gene, Sonic Hedgehog, have been shown by us to be responsible for approximately one quarter of familial cases of HPE. Other genes either related to the hedgehog pathway or located at unrelated defined genetic loci may also contribute to HPE and are the subject of active investigation. We anticipate that many genes important for normal brain development will be identified in the search for genetic causes of HPE.

Detailed Summary:

Holoprosencephaly (HPE) covers a nearly continuous spectrum of midline abnormalities ranging from unmistakable cyclopia with absence of forebrain separation to mild microforms, such a single central incisor.

The objective of these studies is to identify genetic factors (coding and non-coding) that contribute to the pathogenesis of holoprosencephaly (HPE) or related brain malformations. Our approach involves common genetic strategies including mutational analysis of candidate genes. All individuals with overt or subtle clinical findings consistent with the HPE spectrum are eligible to participate. Mutational analysis of our entire coded collection of HPE probands (approximately 600 cases) in selected genes is the principal research method used to determine that a given candidate gene is commonly mutated in HPE. This approach pertains to an individual gene(s) or genetic element(s) as well as to targeted capture panels that study gene sets of hundreds of developmental genes whose involvement in brain development is supported by the basic research literature. We are also asking to include the option of investigating the entire set of genetic factors present in the DNA or RNA of patients who have HPE through a proposed change in the consent documents. Whenever a sequence variant is identified, that is not present in a commercially available control set of samples, attempts are made to test the functional significance of this change on the protein itself, or its expression. Sequence changes with a strong probability of being medically significant will be verified in a CLIA-approved lab (e.g. Muneke lab, for selected genes, or GeneDx) at our expense, before any results are given to the family through genetic counseling. Parental DNA (and rarely that of siblings) is usually obtained at the same time that a proband is enrolled. Typically, these samples are studied only to perform
Sponsor: National Human Genome Research Institute (NHGRI)

Current Primary Outcome:

Original Primary Outcome:

Current Secondary Outcome:

Original Secondary Outcome:

Information By: National Institutes of Health Clinical Center (CC)

Dates:
Date Received: March 27, 2008
Date Started: October 2, 1998
Date Completion:
Last Updated: April 20, 2017
Last Verified: September 26, 2016