What Is Laurence-Moon-Bardet-Biedl Syndrome?

Why This Disorder Has Been Split Into Two Distinct Syndromes

Newborn baby holding Mothers hand. Credit: Sally Anscombe / Getty Images

In previous years, Laurence-Moon-Bardet-Biedl syndrome (LMBBS) was a term used to describe an inherited genetic condition that affected approximately 1 in 100,000 babies born. It was named after the four doctors who initially described the symptoms of the syndrome. 

Since then, LMBBS has been recognized as inaccurate. Instead, it was discovered that LMBBS was actually comprised of two distinct disorders: Biedl-Bardet syndrome (BBS) and Laurence-Moon syndrome (LMS).


The Difference Between Biedl-Bardet Syndrome and Laurence-Moon Syndrome

BBS is a very rare genetic disorder that causes deterioration in vision, extra fingers or toes, obesity in the stomach and abdomen, kidney issues and learning difficulties. Vision issues rapidly deteriorate; many people will become completely blind. Complications from other symptoms, such as kidney problems, can become life-threatening. 

Like BBS, LMS is an inherited disorder. It is associated with learning difficulties, diminished sex hormones and stiffness of the muscles and joints. BBS and LMS are very similar, but are considered different because LMS patients do not show signs of extra digits or obesity in the abdomen. 

Causes of BBS and LMS

Most cases of BBS are inherited. In affects both men and women equally but is not common. BBS affects just 1 in 100,000 in North America and Europe. It is slightly more common in the countries of Kuwait and Newfoundland, but scientists are not sure why.


LMS is also an inherited disease. LMS is autosomal recessive, meaning that it only occurs if both parents carry the LMS genes. Typically, the parents themselves do not have LMS but carry the gene from one of their own parents. 

How They Are Diagnosed

BBS is typically diagnosed during childhood. Visual examinations and clinical evaluations will look for different abnormalities and delays.

In some cases, genetic testing can detect the presence of the disorder before symptoms advance. 

LMS is usually diagnosed when testing for developmental delays, such as screenings for speech inhibition, general learning disabilities and auditory problems

Treatments for the Two Conditions

Treatment of BBS is focused on treating the symptoms of the disorder, such as vision correction or kidney transplants. Early intervention can allow children to live the most normal life possible and manage symptoms, but there is no cure for the disease at this time. 

For LMS, there are no treatments currently approved to handle the disorder. Like BBS, treatment is focused on managing symptoms. Ophthalmic support, such as glasses or other aids, can help worsening vision. To help treat short stature and growth delays, hormone therapy may be recommended. Speech and occupational therapy can improve dexterity and daily living skills. Renal therapy and kidney support treatments may be necessary. 

Prognosis for Biedl-Bartet Syndrome or Laurence-Moon Syndrome

For those with LMS, life expectancy is usually shorter than other people.

The most common cause of death is linked to renal or kidney issues. 

For BBS, renal failure is very common and is the most likely cause of death. Managing renal issues can improve life expectancy and quality of life. 


"Biedl-Bartet Syndrome". National Organization for Rare Disorders, 2015.

"Laurence-Moon Syndrome". Patient.Info, 2015. 

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