In many ways Keenan Cahill is like many other 16 years old. He loves music, and likes to lip-sync to his favorite artists. However, unlike many most 16 yr-olds, when Keenan posts a video of himself lip-syncing on YouTube, he can get up to 37 million hits! His big “break” came when his video of Katy Perry’s “Teenage Dream” came to the attention of Katy Perry herself, who tweeted about it and the rest is history. Keenan has had guest appearances on his videos by 50 Cent, David Guetta and even Jennifer Aniston. He also has his own YouTube channel.
Now all this is pretty remarkable in itself, but now add the fact that Keenan Cahill suffers from a rare genetic disorder called Maroteaux-Lamy Syndrome, also known as MPS-VI. It is a disease of metabolism where the body is unable to break down (“metabolize”) certain complex sugar molecules called glycosaminoglycans (more information below). Diagnosed at the age of one, Keenan has undergone a bone marrow transplant in 1997 to slow down the progression of the disease, and had multiple surgeries including a surgery to relieve pressure on his brain. Currently, Keenan undergoes weekly infusions — enzyme replacement therapy — that doctors hope will stabilize his disorder and extend his life.
Unfortunately, these treatments are expensive, which leads to his most recent video project. Keenan teamed up with two members of the reigning World Series champion San Francisco Giants, Cody Ross and Brian Wilson. The three of them, and Giants’ mascot Lou Seal, got together to perform Taio Cruz’s “Dynamite” in an effort to raise awareness for a charitable event that Ross and Wilson are holding at the team’s May 25th game against the Florida Marlins called: “Dynamite: A Fundraiser For Keenan Cahill.” Here’s the video:
What are Mucopolysaccharidoses? (Source: NINDS)
The mucopolysaccharidoses are a group of inherited metabolic diseases caused by the absence or malfunctioning of certain enzymes needed to break down molecules called glycosaminoglycans – long chains of sugar carbohydrates in each of our cells that help build bone, cartilage, tendons, corneas, skin, and connective tissue. Glycosaminoglycans (formerly called mucopolysaccharides) are also found in the fluid that lubricates our joints.
People with a mucopolysaccharidosis either do not produce enough of one of the 11 enzymes required to break down these sugar chains into proteins and simpler molecules or they produce enzymes that do not work properly. Over time, these glycosaminoglycans collect in the cells, blood, and connective tissues. The result is permanent, progressive cellular damage that affects the individual’s appearance, physical abilities, organ and system functioning, and, in many cases, mental development.
It is estimated that one in every 25,000 babies born in the United States will have some form of the mucopolysaccharidoses. It is an autosomal recessive disorder, meaning that only individuals inheriting the defective gene from both parents are affected.
What are the signs and symptoms?
The mucopolysaccharidoses share many clinical features but have varying degrees of severity. These features may not be apparent at birth but progress as storage of glycosaminoglycans affects bone, skeletal structure, connective tissues, and organs. Neurological complications may include damage to neurons (which send and receive signals throughout the body) as well as pain and impaired motor function. This results from compression of nerves or nerve roots in the spinal cord or in the nerves which go to organs, muscles, and tissues throughout the body.
Depending on the mucopolysaccharidoses subtype, affected individuals may have normal intellect or may be profoundly retarded, may experience developmental delay, or may have severe behavioral problems. Many individuals have hearing loss. Communicating hydrocephalus in which the normal circulation of cerebrospinal fluid becomes blocked over time and causes increased pressure inside the head is common in some of the mucopolysaccharidoses. Surgically inserting a shunt into the brain can drain fluid. The eye’s cornea often becomes cloudy from glycosaminoglycan buildup, and degeneration of the retina and glaucoma also may affect the patient’s vision.
Physical symptoms generally include coarse or rough facial features , short stature with disproportionately short trunk (dwarfism), skeletal irregularities, thickened skin, enlarged organs such as liver or spleen, hernias, and excessive body hair growth. Short and often claw-like hands, progressive joint stiffness, and carpal tunnel syndrome can restrict hand mobility and function. Recurring respiratory infections are common, as are obstructive airway disease and obstructive sleep apnea. Many affected individuals also have heart disease, often involving enlarged or diseased heart valves.
How are the mucopolysaccharidoses diagnosed?
Diagnosis often can be made through clinical examination and urine tests (excess mucopolysaccharides are excreted in the urine). Enzyme assays (testing a variety of cells or body fluids in culture for enzyme deficiency) are also used to provide definitive diagnosis of one of the mucopolysaccharidoses.
How are the mucopolysaccharidoses treated?
Currently there is no cure for these disorders. Medical care is directed at treating systemic conditions and improving the person’s quality of life. Physical therapy and daily exercise may delay joint problems and improve the ability to move.
Changes to the diet will not prevent disease progression, but limiting milk, sugar, and dairy products has helped some individuals experiencing excessive mucus.
Surgery to remove tonsils and adenoids may improve breathing among affected individuals with obstructive airway disorders and sleep apnea. Surgery can also correct hernias, help drain excessive cerebrospinal fluid from the brain, and free nerves and nerve roots compressed by skeletal and other abnormalities. Corneal transplants may improve vision among patients with significant corneal clouding.
Enzyme replacement therapies are currently in use or are being tested. Enzyme replacement therapy has proven useful in reducing non-neurological symptoms and pain.
Bone marrow transplantation (BMT) and umbilical cord blood transplantation (UCBT) have had limited success in treating the mucopolysaccharidoses. Abnormal physical characteristics, except for those affecting the skeleton and eyes, may be improved, but neurologic outcomes have varied. BMT and UCBT are high-risk procedures and are usually performed only after family members receive extensive evaluation and counseling.
For more information, click here to go to the Resounding Health Casebook on the topic.