Data and/or biomaterials in the REGISTRY database are available to investigators. Any member of the EHDN may apply to the Scientific and Bioethics Advisory Committee (SBAC) to use clinical data and/or biomaterials collected through the efforts of EHDN. For the type of data and/or biomaterials available please refer the REGISTRY case report forms. Applicants are requested to submit (submission page) and/or are responsible for:

• Name, address, phone number of the applicant and co-applicants
• Name of the institution of the applicant
• Project title and summary (word limit 250 words)
• a sufficiently detailed description of the project (word limit 1500 words) including an outline of the statistical evaluation (including a power analysis if appropriate, can be uploaded)
• date of application
• Date of requested data access
• The type of data needed (data categories). Please refer to the REGISTRY case report forms (CRFs) for the type of data you require. A clear specification of the information needed will facilitate the provision of data and/or biomaterials
• The number of data sets and/or biomaterials requested
• the source of funding for the project
• approval from any applicable ethical review board (ERB) (upload word document or scanned and uploaded as image file e.g. GIF or JPG)

NB: The preparation of biomaterials involves consumables and labour. For this reason applicants who wish to receive biosamples will have to contribute to the cost this generates. Sample preparation cost and shipment depend on e.g. the number of samples and their destination. Therefore, the total cost may vary. We recommend that applicants contact Central Coordination ( , ) before they submit their application.

Deadlines for applications: The projects will be discussed during the monthly telephone call of the SBAC, if the application is submitted by the first of the respective month.

EHDN Genetic Projects

It is most likely that there will be multiple genetic modifiers of the onset and phenotype of HD that contribute to the final expression of the disease.  Thus, the search for HD modifiers has all the problems of searching for genes that are susceptibility genes in the common diseases that segregate in families to some extent but are not single gene Mendelian disorders, for instance, Type II diabetes or Alzheimer’s disease.  It is important to keep in mind that false-positive findings can serve as a substantial distraction to the field, thus wasting time and money (Todd JA, 2006). We therefore strongly recommend that applications for the use of EHDN DNA for genetic studies should include the following information:

For a new study: a clear prior biological hypothesis underlying the study and some indication of the DNA variants that will be analysed at each step in the study (e.g. number of SNPs/number of genes/specific pathways or networks).  A clear analysis plan should be outlined with the statistical tests to be used indicated.  Please take any multiple testing into account in this description. If the study has been funded by another body please include an outline of the study from this. This should mean that the whole project gets approved once rather than having the subsequent stages returned for further approval at each stage.

For a follow-up study of a significant genetic finding: reference to the previous finding should be included if it is published and some pilot data if it is not.  Pilot data should include sample size used, no of variants tested, statistical test used and most significant p-value.  A power calculation should be included to demonstrate that the number of samples requested has adequate power to replicate the previous result.  If you plan further detailed work once the initial positive result has been validated, then please outline the subsequent steps in the proposed genetic study and the statistical tests likely to be used to analyse these data.  Please take any multiple testing into account in this description. If the study has been funded by another body please include an outline of the study from this. This should mean that the whole project gets approved once rather than having the subsequent stages returned for further approval at each stage.  

John A Todd. Statistical false positive or true disease pathway? Nature Genetics 2006;38: 731 - 733  doi:10.1038/ng0706-731

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