I was doing some dishes last night when your show came on. I wasn't paying much attention until I heard you mention Laurence-Moon-Biedl syndrome. As a geneticist, I'm sure you could understand my intrigue at the report of a chondrosarcoma in a patient with the syndrome. However, when you began reporting the autopsy, you mentioned that the patient had polydactyly. Laurence-Moon-Biedl and Bardet-Biedl syndromes have recently been identified as two distinct conditions. Polydactyly is NOT present in Laurence-Moon-Biedl syndrome, but IS seen in Bardet-Biedl syndrome. The constellation of obesity, hypogonadism, mental retardation, and polydactyly is characteristic of Bardet-Biedl, also an autosomal recessive disorder which would be consistent with having an affected brother. Interestingly, the behavioral phenotype of individuals with BBS is similar to your case with frequent emotional outbursts and violent behavior. However, the only tumor that has ever been associated with BBS is renal cell carcinoma. Some believe that one of the BBS loci may have tumor suppressor functions. It could explain the chondrosarcoma in your patient. However, this has never been reported. I think it's important for your case to be published to make others aware of a potential association.
Nevertheless, thank you for such an informative and intriguing show. I look forward to watching more.
Best regards, Omar Rahman, MD Division of Medical Genetics Stanford University
