Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.
COMPLETED
5735 participants
OBSERVATIONAL
2008-06-01
2021-01-19
Brief Summary
Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.
Detailed Description
Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.
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 commercial lab) 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 limited family studies once a sequence variant of potential medical significance has already been determined. Participation by direct blood relatives is encouraged since virtually all bone fide mutations are either family-specific or de novo. Such family information is critical for the research determination of genetic risk factors and accurate genetic counseling.
The majority of subjects enrolled in this study will continue under the care of their local physician or genetic counselor with limited contact with the NIH investigators. Only rarely will families be seen at the NIH CC. These visits will involve face-to-face genetic counseling of medically significant results, following verification in a CLIA approved lab. This is not a treatment protocol. Our empiric ability to generate medically significant research results is limited by the extensive genetic and other etiologic heterogeneity. Therefore, for most participants this research is not a diagnostic study.
We have modified our procedures to test all new probands for mutations in the four HPE genes (SHH, ZIC2, SIX3 and TGIF). As new genetic elements that confer a risk for HPE are identified, we intend to add additional tests to this panel. Our lab is now certified to receive and test new samples according to CLIA guidelines. However, all previously collected samples will not be considered suitable for diagnostic purposes; hence, a second sample will need to be requested in these cases for CLIA confirmation.
Conditions
See the medical conditions and disease areas that this research is targeting or investigating.
Keywords
Explore important study keywords that can help with search, categorization, and topic discovery.
Study Design
Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.
COHORT
PROSPECTIVE
Study Groups
Review each arm or cohort in the study, along with the interventions and objectives associated with them.
holoprosencephaly (HPE)
individuals with overt or subtle clinical findings consistent with the HPE spectrum are eligible to participate
No interventions assigned to this group
Eligibility Criteria
Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.
Inclusion Criteria
2. Direct blood relatives (typically parents, and occasionally siblings of affected individuals) of patients with HPE are also eligible to participate.
3. Pregnant women with a fetus with imaging evidence of holoprosencephaly. Most pregnancies affected by holoprosencephaly do not survive to term; therefore, pregnant women will be included in the study. DNA obtained from pregnant women (amniocytes and blood) will be analyzed for genetic etiologies. This will allow for recurrence risk assessment and genetic counseling.
Exclusion Criteria
2. Medical condition(s) or cognitive impairment are not in themselves reason for exclusion if in the judgement of the referring physician this would involve no more than minimal risk. We anticipate that children with mental handicaps would be included in the research population. We will make every effort to explain the study for the purpose of assent in a matter that the family feels is both age and developmentally appropriate for that child.
3. We generally review a brief clinical description from the referring physician about a potential research subject to determine that the subject is appropriate to enter into the study. We reserve the right to exclude cases that are clearly not HPE or related to our direct research interests (e.g. HPE cases due to Trisomy 13 or 18 might not be considered directly related to current research). This almost never happens, and we would attempt to make referrals to a more appropriate investigator before a sample is sent to the NIH. Although not desirable, we will accept samples with a suspected diagnosis of HPE where this determination was made by the referring physician independent of any input from our HPE team. In such circumstances, we would likely verify by correspondence that a sample had been received and request further information.
1 Month
ALL
Yes
Sponsors
Meet the organizations funding or collaborating on the study and learn about their roles.
National Human Genome Research Institute (NHGRI)
NIH
Responsible Party
Identify the individual or organization who holds primary responsibility for the study information submitted to regulators.
Principal Investigators
Learn about the lead researchers overseeing the trial and their institutional affiliations.
Benjamin D Solomon, M.D.
Role: PRINCIPAL_INVESTIGATOR
National Human Genome Research Institute (NHGRI)
Locations
Explore where the study is taking place and check the recruitment status at each participating site.
National Institutes of Health Clinical Center, 9000 Rockville Pike
Bethesda, Maryland, United States
Countries
Review the countries where the study has at least one active or historical site.
References
Explore related publications, articles, or registry entries linked to this study.
Belloni E, Muenke M, Roessler E, Traverso G, Siegel-Bartelt J, Frumkin A, Mitchell HF, Donis-Keller H, Helms C, Hing AV, Heng HH, Koop B, Martindale D, Rommens JM, Tsui LC, Scherer SW. Identification of Sonic hedgehog as a candidate gene responsible for holoprosencephaly. Nat Genet. 1996 Nov;14(3):353-6. doi: 10.1038/ng1196-353.
Cohen MM Jr. Perspectives on holoprosencephaly: Part I. Epidemiology, genetics, and syndromology. Teratology. 1989 Sep;40(3):211-35. doi: 10.1002/tera.1420400304.
Cohen MM Jr, Sulik KK. Perspectives on holoprosencephaly: Part II. Central nervous system, craniofacial anatomy, syndrome commentary, diagnostic approach, and experimental studies. J Craniofac Genet Dev Biol. 1992 Oct-Dec;12(4):196-244.
Related Links
Access external resources that provide additional context or updates about the study.
NIH Clinical Center Detailed Web Page
Other Identifiers
Review additional registry numbers or institutional identifiers associated with this trial.
98-HG-0249
Identifier Type: -
Identifier Source: secondary_id
980249
Identifier Type: -
Identifier Source: org_study_id
NCT00341978
Identifier Type: -
Identifier Source: nct_alias