(Note from Webmaster - XLH Network in the following report refers to the name given The XLH Network Inc. prior to incorporation March 2, 2005.)

BALTIMORE, MARYLAND - Dr. Suzanne Jan de Beur, a researcher at Johns Hopkins Hospital, invites anyone who may be interested to participate in a new research study on XLH. Below you will find:

• A short description of the study
• Ideas on what to think about when deciding whether to participate in such a study
• Answers to several questions that can help with

Note: Participants in this study should have XLH

Those attending our upcoming meeting, DC2001, can participate while there, if they wish. They, or anyone else, can instead participate from your home location. If you are interested in being part of this study from home, now or at any later time, contact me privately (emj@super.org or 301-262-8850). I will pass your information on to Dr. Jan de Beur and she will contact you with further information and instructions.

The gene associated with XLH was identified in 1995 and is called PHEX. However, the exact mechanism by which a defective (mutated) PHEX gene results in the low phosphorus (phosphate wasting) of XLH is currently still unknown. We do know that the PHEX gene encodes (directs the creation of) a type of enzyme, called an endopeptidase, which cuts or `cleaves' a separate hormone that is thought to be involved in maintaining the body's phosphate balance. The identity of this hormone is not yet known, but it has been named `phosphatonin'. Much recent XLH research has focused on trying to identify phosphatonin. The new research study at Johns Hopkins Hospital is continuing along this path. Participants in the study will be asked to provide a blood and standard (not 24-hour) urine sample. These will be tested for several of the phosphatonin candidates, including FGF23, the protein created by the gene, shown by Michael J. Econs and colleagues, to be associated with another form of hypophospatemic rickets called ADHR (Autosomal Dominant Hypophosphatemic Rickets). The results of this research could bring us that much closer to understanding the mechanisms that cause XLH and other phosphate wasting disorders.

Before participating in any genetic research study, you should learn about the issues involved. You can find information on these issues and questions to ask at http://www.geneticalliance.org/geneticissues/informedconsent.html Basically you should be able to get answers to certain fundamental questions, ask any other questions you want to ask, and be fully aware of what is involved in the study and the effects it may have on you and your family before you decide to participate.

It is certainly unfortunate timing that this XLH study is just getting underway in the midst of an originally across-the-board ban on all human subject research at the hospital, due to a death that occurred recently in an asthma study where a chemical was inhaled. This was the university's first death of a research volunteer since 1986 and its first death ever of a healthy volunteer. It is expected that federal officials and the university will be working together to get all research studies up and running again as quickly as possible. Our XLH study should be among the first to be given the go-ahead, since there is so little risk in just taking blood and urine samples. So, for those coming in just about 2 weeks to DC2001, we may still be able to participate while there. If not, those interested can still talk to Dr. Jan de Beur and be ready to participate (from home if necessary) as soon as the study can proceed. The same applies to others who wish to participate from home. if you are interested in participating in the study. Dr. Jan de Beur will contact you and will officially sign you up as soon as she can.

For the Hopkins study here are some answers to several of the suggested questions:

Q: Will I need to sign a consent form?
A: Yes. Each participant will receive a copy of the consent form they sign.

Q: What agency is funding the research?
A: The study is sponsored by The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), National Institutes of Health (NIH), USA

Q: What is the purpose of the study?
A: The purpose of the study is to determine if patients with XLH have detectable circulating levels in blood and urine of several proteins including but not limited to FGF23 that may have a role in the phosphate wasting and bone disease. In this study no DNA testing will be done.

Q: Will I be recontacted if changes in the research plan with respect to my disease occurs? Will I need to sign a new consent form?
A: Participants in the initial study will be given an opportunity to donate blood for DNA isolation so we can correlate PHEX mutations to the level of circulating protein. Specific consent, via a new consent form, will be required for this possible second phase of the research. An additional tube of blood would also be needed then. Each person will be given a copy of the new consent form they sign.

Q: Can my blood/urine be used for new studies on my disease without my knowledge/consent?
A: Blood samples may be used in the future for new endocrine tests that apply to your disease.

Q: Can my blood/urine be used for studies on other diseases without my knowledge/consent?
A: No.

Q: What will happen to my stored blood/urine after this project is complete?
A: The samples will be stored in a -80 degree freezer.

Q: What will happen if I decide to withdraw from this study? What will happen to my stored blood/urine if I withdraw?
A: If you withdraw from the study then your samples will be discarded.

Q: What are the benefits of participating in this research? For myself and other family members? For others?
A: It is very likely that you will not benefit directly from these studies. We hope that with a better understanding of the disease, the project will ultimately benefit individuals with these disorders in the future.

Q: How will costs associated with participation in this study be handled?
A: All tests are free. There will be no charge for sample collection, shipping of samples, processing, or testing. Nothing will be billed to insurance.

Q: Is there any compensation for the time involved?
A: No.

Q: What travel expenses are covered?
A: Only parking will be covered. No other travel expenses can be covered.

Q: Will special services be available for me if I need them (interpreters, braille, child care, etc.)?
A: If a person needs an interpreter we can accomodate this. Childcare will not be available.

Q: What are the risks/discomforts of participating in this study?
A: Side effects may include discomfort, bleeding, or swelling at the site where the needle is inserted into a vein. There are no permanent side effects. Please ask questions if you have any concerns.

Q: Will treatment be provided if unexpected problems arise while I am participating in the study? Who will pay for this treatment?
A: If you are injured as a result of being in the study, the services of the Johns Hopkins Hospital or the Johns Hopkins Bayview Medical Center will be open to you in case of any such injury. However, the Johns Hopkins University, the Johns Hopkins Hospital, the Johns Hopkins Bayview Medical Center, and the Federal Government do not have a program to pay you if you are hurt or have other bad results which are not the fault of the study doctors. You and your insurance company will be responsible for payment of any treatment or hospitalization you require if you are injured as a result of being in the study. It is up to you to check with your insurance company before you start this study to find out what your insurance company would pay for.

Q: What are some of the personal issues that could cause harm to me or my family (for example, anxiety, stigma, discrimination)? A: The results will be published in a way that protects the privacy of all participating families and family members.

Q: Will any of the information obtained be distributed?
A: The information obtained will not be shared with others (including insurance companies, employers, or family members.) We will keep the study information private to the extent possible by law. However, state law requires us to report certain contagious diseases or if we find information about child abuse. Also, under certain conditions, people responsible for making sure that the research is done properly may review your study records. This might include people from Johns Hopkins, the National Institutes of Health, or the Food and Drug Administration.

Q: How will confidentiality of the participants be maintained?
A: The confidentialty will be maintained by assigning codes to the samples, making them anonymous.

Q: How will confidentiality of the records be maintained?
A: The confidentiality of the records are maintained by limited access by the investigators. The notebook and file folders are kept in a locked file cabinet.

Q: How will I be informed about the results of this research study?
A: We are forbidden to inform people about their specific results. Copies of any publications that result from your participation would be available upon request.

Q: How will I be informed if you publish information about me and my family?
A: When published work involving patients has emerged it will be announced through the XLH Network.

Q: If new genetic services, tests, or treatments are developed from this research, how will I be told about their availability?
A: Through the XLH Network.

Last modified Aug 8, 2007

XLH is also known as X-Linked Hypophosphatemia (sometimes also spelled as hypophosphataemia), X-Linked Hypophosphatemic Rickets, Familial Hypophosphatemia, Vitamin D-Resistant Rickets (VDRR) Rickets and even Genetic Rickets. Its notable characteristics are bowed legs, short stature, poor teeth formation causing spontaneous dental abscesses, and low blood phosphorus levels.

© 2002-2007, The XLH Network Inc.
The authors of this web site are not medical professionals, and this information does not substitute for medical care. Information on these pages is based on biomedical research, published in peer-reviewed journals, and international research conferences. Additionally, in some cases anecdotal information is provided by subscribers of the F-HYPDRR group, a mailing list for The XLH Network Inc. A complete web-site bibliography is available. Please read our full disclaimer.