Our most recent newsletter has an article on CRISPR, a huge breakthrough for developing gene therapies for syndromes like Bardet Biedl. Today, the New York Times has an article that explains CRISPR in more depth.
In the past year or so, researchers have discovered that the bacterial system can be harnessed to make precise changes to the DNA of humans, as well as other animals and plants.
This means a genome can be edited, much as a writer might change words or fix spelling errors. It allows “customizing the genome of any cell or any species at will,” said Charles Gersbach, an assistant professor of biomedical engineering at Duke University.
It also discusses some of the challenges moving from this breakthrough to actual treatments.
The New Yorker has an article about an enterprising young woman who, with the help of friends and relatives at a research university, created a registry for the rare form of cancer that she suffered.
Although the registry only includes 15 patients so far, it has already yielded important clues for diagnosis and treatment. It’s a great example of why the new BBS Registry hosted at the Marshfield Clinic is so very important. The article does a nice job of explaining a value of a rare disease registry.
Do read it.
Exciting things are happening in the Bardet Biedl community. In this issue of the newsletter you’ll read about our 2014 Conference from June 26-28th at a new venue with a new focus on living with BBS, exciting new research on BBS therapies, and the conversion of the association into a non-profit. You’ll also hear about the new BBS Center of Excellence at the Marshfield Clinic, new fundraising initiatives, and a BBS registry to advance research.
There’s so much going on we can only give an overview of all of these developments in the newsletter. That’s why I hope you’ll join us at the 2014 Conference, keep in touch via our website or Facebook page, and most of all, volunteer to help on one of our projects. I hope you are as encouraged and excited as I am about these developments. If you have questions about the association or about anything in the newsletter, don’t hesitate to get in touch. Looking forward to seeing you in Iowa City soon.
Download the complete newsletter in PDF form here.
Table of Contents:
Our Saturday agenda at the 2014 Conference (June 26-28) is packed with presentations from some of the leading researchers on BBS.
Confirmed speakers include:
Dr. Nico Katsanis, Center for Human Disease Modeling, Duke University:
Dr. Nico probably needs no introduction, but for those new to the community, he has hosted the last two association conferences. He has been a leader in BBS research since before any genes were identified, and has recently identified yet another gene.
Dr. Elise Heon, chief of pediatrics, Hospital for Sick Kids, Toronto: Dr.
Heon spoke at our last conference (you can see a summary of her talk on our website). She has been busy in the meantime with BBS research not only on vision but on obesity.
Dr. Les Biesecker, National Institutes of Health: Dr. Biesecker leads the
BBS research program at NIH and we’re excited to hear about developments there.
We will also be joined by our host researchers for the conference:
Dr. Val Sheffield, University of Iowa: Dr. Sheffield is another groundbreaking researcher on BBS, publishing papers on BBS genes, cilia and the underlying causes of the syndrome.
Dr. Arlene Drack, Wynn Institute for Vision Research, University of Iowa:
Dr. Drack is an ophthalmologist and researcher who is perhaps best
known for her work testing two different therapies for BBS-related vision
loss, TUDCA and gene therapy in BBS3 mice. You can hear Dr. Drack
describe her research here.
After holding our last two conferences in Durham, NC, our 2014 Conference will be held at the University of Iowa. Duke University was a great location so why did we decide to change?
First, many of our members from the Mid-West, Southwest and West
were ready for a conference a bit closer to home.
Second, there is some exciting BBS research happening at the University of Iowa. We wanted as many families as possible to connect with those researchers. The recent announcement of a major gift from Steve Wynn to fund more research on treating retinal degeneration makes it an exciting time to be in Iowa. You can read more about the gift and the research going on at the Wynn Institute for Vision Research at the University in the newsletter. (a limited number of families who are interested will be able to see the doctors at the university the day before the conference).
Third, the location in Iowa is reasonably close to the Marshfield Clinic
Center of Excellence, which allows speakers from the Center of Excellence to come, and for some families to combine a visit to the Center of Excellence with a trip to the conference.
One of the reasons for transforming the association into an officially registered nonprofit was to facilitate fund-raising in support of our mission: improving the lives of all people affected by BBS. Delays in getting certified as a Federal 501©3 have put a kink in some of our plans (see the following page for details), but it hasn’t stopped them.
Our first two major fund-raising projects are partnerships with the Marshfield Clinic and the Wynn Institute for Vision Research at the University of Iowa. We have made arrangements for both organizations to soon begin accepting donations earmarked donations for BBS projects. One such project is the creation of a BBS registry.
You can read all about that in the registry article. The second is an effort to launch a clinical trial of TUDCA to slow retinal degeneration in BBS. Conducting clinical trials is extremely expensive, typically costing in excess of $1 million. There are organizations that grant such large sums for research. We will be raising funds to help support Dr. Arlene Drack and her team at the University of Iowa in pursuing such grants.
Of course, we have a number of additional projects within the association that could move faster with some donations: a new and better website for the association, a revised BBS handbook, a library of research on BBS translated into “plain English”, educational videos about BBS, etc. So if you’d like to donate to the association, or contribute to one of these projects with your time, please contact us!
In our last newsletter, we shared that we were converting the association into an incorporated non-profit that can raise funds. We’ve made some important strides but also hit some significant roadblocks. First the good news: the Bardet Biedl Syndrome Foundation is now an officially incorporated non-profit in the State of Delaware. We chose the name Bardet Biedl Syndrome Foundation so that the organization would be more easily recognizable as a non-profit. However, we are also recognized under the name Bardet Biedl Syndrome Family Association (this is a point of corporate registration known as “doing business as” or dba). Both names work.
We chose to register in Delaware as it is one of the easiest, cheapest and simplest states to register in. As part of the process of registering as a non-profit corporation in Delaware we had to revise our by-laws to comply with state requirements. These changes were relatively minor but do reflect best practices for running a true non-profit organization. If you have any questions about them, please contact us.
Unfortunately, being recognized as a non-profit corporation is only the first step. After registering in Delaware, you have to go through an additional process to be recognized as a federal non-profit with a 501©3 designation. This is the designation necessary to accept tax-deductible donations. The application is an arduous process in and of itself, but if you’ve followed the national news this year you know that there has been some controversy over how the IRS has processed applications for federal non-profit status. As a result, the IRS stopped processing all applications for several months. That delay was compounded by the federal government shutdown this fall. The bottom line is the IRS is approximately 70,000 applications behind in processing. It may take as much as a year before we get our approval. The only thing that the delay affects is our ability to accept tax deductible donations directly. We can still accept donations and continue our normal operations. We’ve also made arrangements with the Marshfield Clinic and the University of Iowa to accept donations for specific BBSFA-endorsed projects. (Read more about that in the fundraising update).
Over the last ten years research on the genetics of BBS has progressed by leaps and bounds. We know about almost 20 BBS genes. We know about cilia, intraflagellar transport and the BBSome group of proteins. That genetic knowledge has helped us understand some of the symptoms of BBS, from retinal degeneration to decreased sense of smell. But there are plenty of areas where mysteries remain: why does a cilia defect cause obesity? Why do people with BBS have low muscle tone? Why do some people with BBS have autistic tendencies? Why does BBS affect people with the same gene so differently?
These are important mysteries to solve because they are the next step toward the ultimate goal: finding effective treatments for the symptoms of BBS. So how do we solve these mysteries? And how do we accelerate
the progress toward finding treatments? The first challenge is gathering information about how BBS affects people. Because there are so many genes and every person with BBS has a different set of symptoms, it’s
very hard to establish patterns. To see those patterns and to know that they are real, researchers need access to a larger pool of data about BBS families. To be able to test hypotheses and develop treatments they
need to be able to easily find BBS families with certain genes and certain symptoms.
To save time and money in the process, researchers need access to clinical information—bloodwork, sonograms, ERGs, OCTs, ECGs—so they don’t have to redo all those tests. To attract funding for clinical trials
of possible treatments, researchers need to show the organizations that fund such trials that they can find enough patients to participate in studies. In other words, the most important step right now to accelerate
understanding BBS and developing treatments and courses of care is a registry.
A registry is a central store of genetic and clinical data for patients affected by a particular syndrome or disease. You may have heard of the National Bone Marrow Registry—a store of information about all the people who are in need of a bone marrow transplant or are willing to donate bone marrow.
Many rare diseases have registries because they are so useful to researchers. The Foundation Fighting Blindness is launching a registry for patients affected by retinal degeneration. That registry however will only collect data about vision, not any other symptoms. That’s why we need a BBS Registry.
In short, a registry:
• Brings together genetic and clinical information
• Accelerates research into effective treatments
• Attracts researchers
• Makes it easier for researchers to find funding.
Building a registry is not a small undertaking. Because a registry contains highly sensitive medical information it has to meet all the highest standards for privacy and security. Only screened researchers get access to the registry. Each person’s record is anonymized so that specific individuals can’t be identified without their explicit consent. The technology has to be in place to allow the registry to efficiently store and sort a large volume of information.
As part of its work establishing the Center of Excellence, the Marshfield Clinic has agreed to host and partially fund the development of a BBS registry. It’s a big help to have the registry hosted at a clinical center. All patients who visit the Center of Excellence can easily transfer their medical records for the registry. Marshfield also has all the necessary experience to manage compliance with federal HIPAA and privacy regulations. Dr. Bob Haws has already begun to collaborate with the National Institutes of Health rare disease registry group to design the BBS registry. However, a great deal of technical work needs to be done to actually build the registry. And that costs money. We are making the registry a top priority for fundraising and will be launching a number of programs in conjunction with the Marshfield Clinic to allow members of the Bardet Biedl Syndrome to participate in fundraising efforts. Stay tuned for more information about the BBS Registry. We’ll be talking more about it and gathering data for the registry from families at our 2014 conference.
The new BBS registry gathers information about BBS families for researchers. We are also launching a BBSFA directory to gather information for families.
We want all members of BBSFA, new and old, to be able to easily find other families in similar circumstances. That may be others in your state who have dealt with social service agencies. It may be finding parents of children of similar age. It may be creating a group of BBS adults who want to talk about job searches. It may be seeking help finding a “BBS-friendly” endocrinologist in your area.
Whatever the case, right now it is too hard to connect with other BBS families with shared interests. Making it easier to connect is the goal of the BBSFA directory. It’s a directory that only members of the association will have access to. It will contain basic information about each family or individual that is a member of the association and whatever contact details you choose to share. If you’re registering for the 2014 conference, the information for the directory is part of the registration process. It will also be part of the membership application from now on. If you’re already a member but aren’t yet registering for the conference, please contact us.
A new technology holds promise for rapidly accelerating progress on gene therapy. Gene therapy in use in current approaches to treating retinal degeneration use a modified, harmless virus to deliver a “good” gene to cells. While that technique has shown promise, it’s slow because researchers have to carefuuly calibrate the right amount of the good gene to deliver—too much of a good thing can definitely be bad. The technique also leaves the defective gene in place, which can produce other complications.
The new technique is called CRISPR. It’s based on a process that bacteria use to defend themselves. CRISPR allows a precise gene to be cut out of a strand of dna and replaced with a different gene. Targeting and replacing specific genes solves some of the problems of delivering good genes via virus. Since researchers know which gene is bad and what a good one is, they can simply replace the bad gene with a good one. That means there is less worry about getting the dose right or possible harmful interactions with the defective gene.
These are still very early days—CRISPR was only developed in the last 18 months. A series of papers published in scientific journals this summer verified that the technique works in a wide variety of applications. That has led to rapid adoption of the technique in labs. Dr. Sheffield and Dr. Drack are already working with CRISPR at the University of Iowa. In November, a new company was founded by the scientists who discovered CRISPR specifically to focus on using the technique for gene therapy. We’ll be hearing more about CRISPR and
its application to the development of therapies for BBS this summer at our conference.
By: Gerry & Mary Morris
Our family traveled to the Marshfield Clinic for the first Bardet Biedl Syndrome (BBS) Center of Excellence appointments July 10-13, 2013. We live in Phoenix, Arizona and have had issues finding quality health care for our two daughters, Ashley, 20 and Carly, 12 both affected with BBS.
Visiting the BBS Center of Excellence has changed our ideas in defining what really great care is! For example, all the providers and specialists at the Marshfield Clinic were very knowledgeable about BBS. This is
something that has honestly NEVER happened in the 20 years we have been dealing with this syndrome. The Marshfield Clinic medical staff was not only knowledgeable, but was able to discuss research they had
reviewed and how that related to our daughters’ specific needs across the three days of various medical appointments. We witnessed daily, medical staff communicating effectively with us and each other prior to our visit to ensure our girls had the best care possible. For instance, we saw Dr. Stuart Waltonen for psychological testing in the morning and during our appointment with Dr. Hema Murali that afternoon, she mentioned that Dr. Waltenen had noticed something about our daughter Carly that concerned him. Dr. Murali was able to tailor her care of our daughter based on the observations of another specialist in an unrelated field only hours before. This high-level of caring and communication across specialists is unheard of with our health care at
We are especially thankful for Dr. Robert Haws. He listened to our pleas and cared enough to make a difference in not just my daughters’ lives, but in the lives of every person with BBS that traveled to the Marshfield
Clinic. Dr. Haws is an outstanding medical professional that has historically provided exceptional care to our girls. He actually diagnosed Ashley with BBS when she was just a toddler, and cared for her since her birth in 1993. When she was in need of a kidney transplant, we relocated our family to Phoenix, Arizona to allow Ashley to have the best care possible before, during and post-transplant under Dr. Haws. Coming to the Marshfield Clinic, to the Center of Excellence for BBS, is a trip we plan to take yearly because we want the best quality of care for our daughters.
Dr. Haws and the Center of Excellence is clearly the best care possible for those living with BBS. Dr. Haws has also shown great support for the Bardet Biedl Syndrome Family Association (BBSFA) here in the United States for several years. He has traveled to the BBSFA Family Conference to speak about kidney function in BBS and has answered countless questions and calmed many fearful parents on our BBS family chat group. He has become a BBS “subject matter expert” and has shown tremendous dedication to a syndrome that is virtually unknown in our country today. In the past, families with BBS who wanted specific treatment by physicians knowledgeable in BBS had to travel to the Great Ormond Street Hospital for Children in London, England. This was of course not something that most families living in the United States could typically afford. Thankfully, we now have a dynamic, cutting edge Center of Excellence of our own at the Marshfield Clinic that rivals any of the clinics in London, England and can be a beacon of hope for both BBS patients and their families living in the United States.
A letter to BBS families from Dr. Bob Haws, director of the BBS Center of Excellence at the Marshfield Clinic
Dear BBS family members,
As a physician caring for children with BBS I am impressed that a leading priority for you and others is preserving vision for your loved one or yourself. As a father of a wonderful daughter affected by blindness I understand your passion. A second priority for individuals with BBS is prevention of obesity by appetite control. The two issues of loss of vision and appetite control are critical to almost every child with BBS. The University of Iowa has published encouraging research reporting that tauroursodeoxycholic acid (TUDCA) slowed retinal degeneration in an animal model of BBS. Furthermore TUDCA resulted in decreased food consumption and weight loss in the animals.
A clinical trial of TUDCA in individuals with BBS has been proposed but not yet initiated. Such clinical trials are very expensive. Dr. Arlene Drack at the University of Iowa is pursuing funding. The Foundation Fighting Blindness has expressed interest in considering TUDCA research. I strongly encourage you to write Dr. Steve Rose, Chief Science Officer at the Foundation Fighting Blindness expressing support, and your family’s interest in participating in a clinical trial of TUDCA in individuals with BBS. Contact information for the Foundation Fighting Blindness is provided below:
Foundation Fighting Blindness
7168 Columbia Gateway Drive, Suite 100
Columbia, MD 21046
Toll Free: (800) 683-5555
Important points to consider in your communication may include the following:
1) The treatment results with TUDCA in an appropriate animal model of BBS are extremely encouraging. Translational research, taking research from laboratory animals to humans, is critical. This research is integral
to the objective of the FFB.
2) Bardet-Biedl syndrome provides an important disease model for other degenerative retinal diseases. Successful identification of effective therapy in BBS may be applicable to other diseases causing blindness.
3) The Bardet-Biedl Syndrome community is a growing community with a commitment to research. You may consider stating that you represent one individual anxious to support and participate in this research.
4) TUDCA provides hope to the BBS community not only for the potential benefit on vision but also for the appetite suppressing effect that will improve the quality of life for individuals with BBS.
Please take time to send your support for this research. Your voices are extremely powerful and need to be heard.
While we are hopeful for a TUDCA clinical trial, remember that there are no reliable and safe sources of TUDCA available for individuals today. Attempting to self-medicate with TUDCA is dangerous.
Bob Haws, M.D.
Treatment Center for Bardet-BIedl Syndrome and Related Ciliopathies
The basic info is below. You can read more about the conference here.
DATE: June 26 to 28, 2014
LOCATION: University of Iowa, Iowa City, Iowa
Closest airport: Cedar Rapids, Iowa.
REGISTRATION FEE: $100 for the first adult in a family, $80 for each additional adult who will be attending sessions. $50 for each child under the age of 18. Tickets just for the banquet are available for $30 per person.
- Attendance at all sessions on Friday and Saturday
- Lunch on Friday and Saturday
- The Association banquet on Friday night (nominations for 2014-2016 board positions will take place at the banquet)
- A family association membership (and one vote in association business matters) is included in the price for the first adult.
- A BBSFA T-shirt
HOTEL ACCOMMODATIONS: We have arranged for a group discount at the Heartland Inn in Coralville, IA. It is just a few minutes from the conference venue. The rates are $75 for two queens; $80 for a king and a pull out couch; $100 for a suite. Additional days before and after the conference are available at the above rate. Continental breakfast and a light dinner for everyone in your party are included in the above rate. A shuttle will be available to transport guests to the conference venue.
Activities for Children: We will have space at the conference venue set aside for children’s activities. There will be volunteers in these rooms, but this will not be “drop-off” child care. Parents will need to check on their children regularly and volunteer to staff the room during a few sessions.
The 2014 BBSFA Conference, June 26-28, 2014, will be bigger and better than ever before. The most obvious change is that we’ll be gathering at the University of Iowa in Iowa City this time. You can read more about our venue and hosts below.
Click here to register now, or read on for more info.
What may not be as obvious is that the conference will focus not only on BBS research, but we’ll have a whole day devoted to living with BBS. On Friday, our speakers will all be doctors and specialists who are working with a number of BBS patients and families. They’ll be sharing what they’ve learned about BBS psychology, adapting to vision loss, exercise and nutrition and many other topics. On Saturday we’ll be hearing from BBS researchers from several different research efforts (see the agenda below for our confirmed Saturday speakers).
In addition to our speakers, we’re also setting aside time for BBS families to interact with each other. You’ll be able to talk to other families who face similar issues or are at a similar stage to share ideas and support. Of course, we’ll also have updates on association projects, our banquet (including some special awards), and elections for association board positions.
All-in-all it will be a packed two days plus. The “plus” points to two other important parts of this year’s conference. First, the University of Iowa will have limited slots for visits with some of their specialists and genetic testing for families who don’t have a genetic diagnosis on Thursday before the conference. If you’re interested in learning more, send an email to Darla Mansker, BBSFA secretary at firstname.lastname@example.org. Second, the BBS Center of Excellence at the Marshfield Clinic will be holding clinic appointments before and after the conference. Marshfield, WI is about a six hour drive from Iowa City, so it will be relatively easy to combine visits. Spots on the clinic schedule are always in high demand, so if combining the conference with a visit to the Center of Excellence sounds appealing, be sure to contact Dr. Haws from Marshfield right away (email@example.com).
Here’s a quick look at the Conference Agenda:
Thursday: Arrive, appointments at University of Iowa, genetic testing and genetic samples
9:00 Welcome and Opening
10:00 to 12:00: Living with BBS Breakout Sessions (psychology, metabolism, nutrition and exercise, etc.)
12:00: Lunch with BBS Family Groups–meet other families like you
1:00 to 3:00: Living with BBS Breakout Sessions
3:00: BBS Center of Excellence
4:00: Ask the Doctors: A chance for you to ask your burning questions about living with BBS
6:30: Banquet: Meet BBS families in your area; Special Awards; Nominations for BBS Family Association board positions
9:00: BBS Research: Dr. Nico Katsanis, Dr. Elise Heon, Dr. Les Biesecker
11:00: BBS Registry
12:00 Lunch and BBS Family Association Board Elections
1:00: BBS Reseach: Dr. Arlene Drack, Dr. Bud Tucker, Dr. Val Sheffield
4:00 Ask the Researchers
Our Saturday agenda is packed with some of the leading researchers on BBS. Confirmed speakers include:
Dr. Nico Katsanis, Center for Human Disease Modeling, Duke University: Dr. Nico probably needs no introduction, but for those new to the community, he has hosted the last two association conferences. He has been a leader in BBS research since before any genes were identified, and has recently identified yet another gene.
Dr. Elise Heon, chief of pediatrics, Hospital for Sick Kids, Toronto: Dr. Heon spoke at our last conference (you can see a summary of her talk on our website). She has been busy in the meantime with BBS research not only on vision but on obesity.
Dr. Les Biesecker, National Institutes of Health: Dr. Biesecker leads the BBS research program at NIH and we’re excited to hear about developments there.
And of course, our hosts:
Dr. Val Sheffield, University of Iowa: Dr. Sheffield is another groundbreaking researcher on BBS, publishing groundbreaking papers on BBS genes, cilia and the underlying causes of the syndrome.
Dr. Arlene Drack, Wynn Institute for Vision Research, University of Iowa: Dr. Drack is an ophthalmologist and researcher who is perhaps best known for her work testing two different therapies for BBS-related vision loss, TUDCA and gene therapy in BBS3 mice. Watch a video of Dr. Drack describing her research here.
This is a summary of a session a the recent Partnering for Cures conference. It illustrates the importance of creating a registry and collecting natural histories from patients, two things the association is working hard on setting up right now.
In 1983, the year the Orphan Drug Act became law, there were just two drugs approved for rare diseases. In 2011, 26 drugs were approved to treat rare conditions. In the 30 years since the Orphan Drug Act created incentives for drug developers who pursue therapies for conditions that affect fewer than 200,000 people, more than 360 drugs have been licensed for 449 rare conditions. Some command high prices, with more than 10 drugs for rare disease topping $200,000 per patient annually.
The 2014 BBS Family Association will cover nearly twice as many topics as we’ve ever been able to before. We’re designing the exact agenda now and want to hear from you. What topics are you most interested in hearing about? Tell us by answering this very brief survey.
The first day of the conference will feature a variety of doctors who are working with BBS patients. The second day will focus on research. For the first day we’re trying to make sure we allot time to cover the issues that are most of concern. This is your chance to help us shape the agenda. So take just a few minutes to fill out the survey please!
We’ve officially set a date and site for our 2014 Conference.
We’ll be meeting together at the University of Iowa in Iowa City, IA from June 26th to the 29th. Our hosts are Dr. Val Sheffield and Dr. Arlene Drack. You may recognize Dr. Sheffield’s name from the article about BBS and cilia from the Howard Hughes Medical Institute, “The Importance of Being Cilia.” Unfortunately the Institute has changed their website and the piece is no longer available. Contact us if you’d like a PDF copy.
Dr. Drack has made waves recently with her work on TUDCA, a chemical compound, and BBS. Early results suggest some promise that TUDCA may help slow retinal degeneration in some BBS patients.
The first thing you might notice about the conference is that it’s four days. We’ll open the conference on Thursday evening and a have a few optional community gatherings on Sunday morning.
The added time for the conference will be used to add two important elements to the conference based on feedback from members:
1) More information on living with BBS from doctors who are treating patients.
2) More opportunities to meet, interact and learn from other BBS families.
More information is coming in the next weeks and months as we finalize the schedule, set prices to cover our costs and begin the registration process.
Watch this space!
During a conversation with Dr. Arlene Drack of the University of Iowa I learned several surprising things about protecting vision. I wanted to post these points quickly because every day we can preserve the retinas of people with BBS matters:
- Large-brimmed hats are at least as good, if not better, than sunglasses at blocking the sun’s harmful rays from retinas. Ideally people with BBS should wear both when out in the sun, but the hats are more important.
- While most of what you read about protecting vision from the potentially damaging effects of the sun is about UV rays, these are not the rays that people with BBS need to worry about. UV rays are absorbed by the lens of the eye and do not reach the retina (which is why we can’t see UV light). The danger in UV rays is that they can contribute to cataracts later in life—well after people with BBS have lost most retinal function. The rays that do damage to retinas are in the blue wavelength.
- The way to block these rays is with lenses that are brown or yellow, not the more common grey or black of most sunglasses.
I attended the Foundation Fighting Blindness Visions 2013 conference this past week and had a chance to listen to and meet with a number of noted national experts on retinal degeneration, and some with specific expertise on BBS.
I’ll be posting various updates from conversations and sessions at the conference over the next week. The first one is a discussion of the differences and pros and cons of ERGs and OCTs, two different approaches to measuring retinal degeneration.
A brief primer on each.
An Electro-Retinograph or ERG tests the electrical response of various cells in the retina, including rods and cones. Various flashes of light and checkerboard patterns are projected and the electrical impulses are measured with electrodes attached to the cornea and/or skin near the eye.
Optical Coherence Tomography or OCT uses very high wavelength light to create a three-dimensional image. In Ophthalmology, the light is shone onto the retina; the scattering and reflection of the light is measured, and a micrometer resolution image of the retina is created. It is most similar to a sonogram which similarly creates three-dimensional images based on the scattering and reflection of soundwaves. OCTs however are much higher resolution than sonograms. A retinal OCT can show, in high resolution and a great deal of detail, the thinning of the retina that happens with BBS-related retinal degeneration.
Historically, ERGs were used as a method to diagnose BBS. Before there were genetic tests for the BBS genes, a finding of retinal degeneration without other explanations (such as a family history of RP) with other features of BBS was key to diagnosis.
If there is a genetic finding of BBS, the use of ERGs or OCTs is mainly to understand the progress of retinal degeneration. For that purpose, there are several major differences between the two tests:
1. An ERG measures the specific responses of rods and cones. While most people with BBS experience rod-cone dystrophy, meaning the rods deteriorate somewhat more rapidly than cones (beginning with night blindness and narrowing of field). But some people have cone-rod dystrophy which affects vision very differently.
2. An OCT is a quick and painless test, requiring only that a person stare at a small blue light for a few seconds. An ERG can be very unpleasant, and in children usually requires sedation (which carries significant risks).
3. An OCT can detect cysts in the vitreous fluid known as cystoid macular edema which some patients in BBS develop and which can further limit vision. The good news is that these cysts are treatable with drops—so there’s good reason to detect them and deal with them.
For either test, one reason to have the test done at regular intervals is to have an ability to track the progress of degeneration. This won’t tell you anything better than other tests of functional vision, but it may help future clinical trials to have an objective measurement of the pace and progress of degeneration to compare against.
Ultimately this is a decision for each family and their doctors to make. There is some usefulness to both tests and some downsides to each.