Bardet-Biedl Syndrome & Laurence Moon Syndrome

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This is no longer termed “Laurence-Moon-Bardet-Biedl syndrome.” An individual can have either “Laurence-Moon syndrome” or “Bardet-Biedl Syndrome,” both rare genetic disorders with overlapping characteristics.

Bardet-Biedl is a syndrome (set of related attributes) caused by a genetic mutation and characterized by the eye condition known as cone-rod dystrophy, in addition to a variety of features that may include abnormal weight gain in the trunk (and related health issues), extra fingers or toes (polydactyly), intellectual disability, developmental delay, kidney issues, speech problems, inability to smell, and genital abnormalities.

We will focus on the eye condition associated with Bardet-Biedl syndrome: cone-rod dystrophy.

Cone-rod dystrophy is a group of more than 30 inherited diseases that, over time, cause deterioration of the specialized light-sensitive cells of the retina. These are the rods that densely cover the peripheral, or outlying, portion of the retina and are responsible for peripheral vision and vision in low light, and the cones that more densely cover the central portion of the retina and are responsible for color perception, detailed vision, and central vision.

Individuals with cone-rod dystrophy as part of the syndrome Bardet-Biedl typically experience decreased sharpness of vision (not correctable with eyeglasses), poor night vision, loss of color perception, and blind spots within the peripheral (outlying) vision that eventually lead to total loss of peripheral vision.

Cone-rod dystrophy can be stable (usually present at birth and does not worsen over time) or progressive (age of onset varies greatly and will worsen over time).

How Is Bardet-Biedl Syndrome Diagnosed?

As several characteristics of Bardet-Biedl syndrome are identified, a team of medical professionals will begin to piece together the puzzle and diagnose a child.

Regarding the eye condition associated with Bardet-Biedl, the first symptoms include decreased detailed vision which is not correctable with glasses as well as poor night vision. You may also notice light and glare hurting your child’s eyes and limiting her vision.

A dilated eye examination will reveal degeneration of the rods and cones, and the child will be given a diagnosis of cone-rod dystrophy.

Are There Treatments for Bardet-Biedl Syndrome?

There is currently no cure for Bardet-Biedl syndrome; however, surgery, hormone treatments, medication, and therapies will likely be recommended for the associated medical issues.

There is also currently no cure or standard, proven treatment for cone-rod dystrophy. Some ophthalmologists believe that treatment with high doses of Vitamin A can slow the progression.

It is important to protect the eyes from further damage from the sun by using quality sunglasses and a hat while outdoors in the daytime.

How Would You Describe the Eyesight of Bardet-Biedl Syndrome and How Will My Child Function with It?

Cone-rod dystrophy typically manifests with loss of sharp visual acuity which is not correctable with glasses, severe sensitivity to light (photophobia), and blind spots in the peripheral vision (scotomas), progressing to total peripheral field loss.

Your child’s teacher of students with visual impairments should perform a functional vision assessment to determine how your child uses his or her vision in everyday life and a learning media assessment to determine which senses your child primarily uses to get information from the environment. These assessments, along with an orientation and mobility assessment conducted by a mobility specialist, will give the team information needed to make specific recommendations for your child to best access learning material and his or her environment.

Loss of sharp visual acuity makes it difficult to recognize faces and facial expressions, access information from a classroom board or wall, view a speaker or performance, read print, and perform visual tasks of fine detail such as threading a needle. In order to best use remaining vision, your child can be taught to increase the contrast of the environment, increase the contrast of print by using a CCTV or screen-magnification software, and increase task lighting. Furthermore, your teen should sit in a preferred seat of a room for optimal viewing, whether near or far from the lecture or activity.

Bright sunlight and glare can cause significant discomfort and inability to see (this is known as a “whiteout”). Your child may benefit from specialized sunglasses (amber-tinted lenses) and use of a brimmed hat while outdoors as well as shutting blinds while indoors if glare is present.

An individual with loss of peripheral vision has some degree of “tunnel vision” making it difficult to gather comprehensive visual information in an environment; he or she will benefit from learning visual efficiency skills such as scanning an environment in an organized manner, and possibly utilizing a reverse telescope to see an entire image within the remaining field of vision. Additionally, the individual is likely to bump into side-lying and low-lying obstacles; he or she should utilize orientation and mobility skills, such as the use of a cane, to avoid obstacles. Orientation and mobility (travel training) becomes necessary to navigate safely with the use of a cane and public transportation. Evening travel may be further aided by the use of an infrared night scope.

If your child loses central vision in addition to lost peripheral vision, he or she must be taught to complete tasks without use of vision. Your child may be taught braille, screen-reading software to use the computer, and techniques for performing life-skills and academic tasks from the teacher of students with visual impairments and orientation and mobility specialist. Better yet, your child should begin learning the aforementioned accommodations in preparation for complete loss of sight.

What Is Laurence-Moon Syndrome?

Previously diagnosed as “Laurence-Moon-Bardet-Biedl syndrome,” this is now differentiated as “Laurence-Moon syndrome” or “Bardet-Biedl Syndrome,” both rare genetic disorders with overlapping characteristics.

Laurence-Moon is a syndrome (set of related attributes) caused by a genetic mutation and characterized by the eye condition known as retinitis pigmentosa (RP) in addition to a variety of features that may include speech delay, learning disability, short stature, kidney disease, type 2 diabetes, polydactyly (extra fingers), obesity, weakness of the legs, and reproductive issues (including small male genitalia).

We will focus on the eye condition associated with Laurence-Moon syndrome, retinitis pigmentosa.

Retinitis pigmentosa (RP) is a term indicating your child has one of a group of (generally hereditary) conditions affecting the retinas, the light-sensitive nerve tissue lining the back of the eyes. The retina contains photoreceptor cells that convert incoming light into electrical impulses which are carried to the brain and interpreted as visual images. There are two types of photoreceptor cells: the rods, which more densely cover the peripheral, or outlying, portion of the retina and are responsible for peripheral vision and vision in low light as well as the cones, which more densely cover the central portion of the retina and are responsible for color perception, sharp visual acuity (detailed vision), and central vision.

Retinitis pigmentosa typically deteriorates the rods, followed by the cones. The degeneration progresses over time and can lead to total blindness.

For a more detailed description of retinitis pigmentosa, visit VisionAware’s guide to RP.

How Is Laurence-Moon Syndrome Diagnosed?

As several characteristics of Laurence-Moon are identified, a team of medical professionals will begin to piece together the puzzle and diagnose a child with Laurence-Moon.

If your son or daughter is having difficulty navigating or seeing in dimly lit environments and/or if he or she is beginning to routinely bump into low-lying, side-lying, or overhanging objects, your child’s vision and eye anatomy should be evaluated by an ophthalmologist.

If visual field testing and/or a dilated eye examination detect degeneration of the rods and cones, the child will be given a diagnosis of retinitis pigmentosa.

Additionally, if a family member has a diagnosis of RP, your child’s peripheral vision and eyes should be examined by an ophthalmologist. Genetic testing is also available to help determine an early diagnosis. An early diagnosis enables a person with the disease to prepare for its progression.

Are There Treatments for Laurence-Moon Syndrome?

There is currently no cure for Laurence-Moon syndrome; however, surgeries, hormone treatments, and therapies will likely be numerous for the medical issues associated with Laurence-Moon.

There is also no cure for retinitis pigmentosa; however, some ophthalmologists believe that treatment with high doses of Vitamin A can slow the progression of RP.

It is important to protect the eyes from further damage from the sun by using quality sunglasses and a hat while outdoors in the daytime.

To learn about current research advances for retinitis pigmentosa treatment, including gene therapy and drug clinical trials, read Foundation Fighting Blindness: Retinitis Pigmentosa Research Advances.

How Would You Describe the Eyesight of Laurence-Moon Syndrome and How Will My Child Function with It?

Retinitis pigmentosa typically manifests with poor vision in dimly lit environments, termed “night blindness.” Traveling by car, bike, or foot; performing tasks; and recognizing people or objects becomes increasingly difficult in “evening light.”

Orientation and mobility (travel training) becomes necessary to navigate safely with the use of a cane and public transportation. Evening travel may be further aided by the use of an infrared night scope. Additionally, a well-lit room and additional use of task lighting (lamps or other lights) will be helpful for the individual to read, obtain details, and utilize vision to participate in activities.

Retinitis pigmentosa typically advances to include progressive peripheral field loss.

An individual with loss of peripheral vision has some degree of “tunnel vision” making it difficult to gather comprehensive visual information in an environment; he or she will benefit from learning visual efficiency skills such as scanning an environment in an organized manner and possibly utilizing a reverse telescope to minimize the appearance of an image in order to see its entirety within the remaining field of vision. Additionally, the individual is likely to bump into side-lying and low-lying obstacles; he or she should utilize orientation and mobility skills, such as the use of a cane, to avoid obstacles.

As retinitis pigmentosa progresses, sharp visual acuity, central vision, and color vision may begin to deteriorate, possibly resulting in total blindness.

If your child loses central vision in addition to lost peripheral vision, he or she must be taught to complete tasks without the use of vision. Your child may be taught braille, screen-reading software to use the computer, and techniques for performing life-skills and academic tasks from the teacher of students with visual impairments and orientation and mobility specialist. Better yet, your child should begin learning the aforementioned accommodations in preparation for complete loss of sight.

Please understand that throughout the progression of retinitis pigmentosa, it is common for bright sunlight and glare to cause significant discomfort and inability to see (this is known as a “whiteout”). Your child may benefit from specialized sunglasses (amber-tinted lenses), use of a brimmed hat while outdoors as well as shutting blinds while indoors if glare is present.

Your child’s teacher of students with visual impairments should perform a functional vision assessment to determine how your child uses his or her vision in everyday life and a learning media assessment to determine which senses your child primarily uses to get information from the environment. These assessments, along with an orientation and mobility assessment https://aphconnectcenter.org/familyconnect/education/ecc/orientation-and-mobility/ conducted by a mobility specialist, will give the team information needed to make specific recommendations for your child to best access learning material and his or her environment.