WHAT IS BARDET-BIEDL SYNDROME?
Bardet-Biedl syndrome (BBS) is a condition that affects several parts of the body. It runs in families and may severely impair the sufferer.
BBS is also known as Laurence-Moon-Bardet-Biedl syndrome (LMBBS).
One of the major features of Bardet-Biedl syndrome is loss of vision. Loss of vision occurs as the retina, that is the light sensing tissue or layer at the back of the eye, fails gradually.
The problems appear initially as difficulty in seeing in the dark. This is seen in childhood as a slow onset condition. This is followed by development of blind spots in vision that leads to falls and knocks initially.
Over time, these blind spots enlarge and turn into a tunnel where only the center is visible. With time the central clear area also clouds.
By the time the child reaches adolescence or early adulthood, he may become legally blind.
Another characteristic feature is obesity. There is typical abdominal obesity that begin in early childhood and continues throughout life. This may give rise to other complications like type 2 diabetes, high blood pressure and abnormally high levels of cholesterol.
Typically there may also be presence of extra fingers and/or toes along with mental retardation, learning problems, and abnormalities of the genital organs.
For more information on Bardet-Biedl syndrome, please visit the following websites:
GENETICS & INHERITANCE
Bardet-Biedl syndrome is a genetically inherited condition. It results from mutations in at least 14 different genes in the body. These are commonly called BBS genes.
It is found that these genes help make the hair like cellular structures called cilia. These cilia are involved in cell movement, different chemical signaling pathways perception of sensory input (such as sight, hearing, and smell) etc. The BBS genes code for proteins that maintain the functions of the cilia. Defects in these genes lead to defective cilia.
The inheritance of Bardet-Biedl syndrome is autosomal recessive. This means parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene but have no symptoms of the condition (carriers of the gene).
Click here for explanation of Inheritance Patterns
TREATMENT & RESEARCH
There is no cure for BBS, therefore, treatment focuses on managing the symptoms. For example:
- Vision impairments – Low vision aides and mobility training are beneficial.
- Obesity – A dietician can work with the family to create an appropriate diet regimen.
- Speech disorder – Speech therapy can help children with their communication skills and parents can be taught exercises to use at home to improve their child’s ability to communicate.
- Kidney problems – There are several types of kidney problems associated with LMBBS and the treatment varies accordingly. Kidney issues can be treated with medications and in rare instances, surgery (transplantation).
- Polydactyly – Skin tags can be tied off at birth and extra digits can be removed surgically.
Information regarding current research can be found here:
Below are the links to the organizations providing care and support services to people with impaired vision.