Maroteaux–Lamy syndrome (also known as "Mucopolysaccharidosis type VI") is a form of mucopolysaccharidosis

Mucopolysaccharidosis

Mucopolysaccharidoses are a group of metabolic disorders caused by the absence or malfunctioning of lysosomal 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...

 caused by a deficiency in arylsulfatase B

Arylsulfatase B

Arylsulfatase B is an enzyme associated with mucopolysaccharidosis VI.Arylsulfatase B is among a group of arylsulfatase enzymes present in the lysosomes of the liver, pancreas, and kidneys of animals. The purpose of the enzyme is to hydrolyze sulfates in the body. ARSB does this by breaking down...

 (ARSB). It is named after Pierre Maroteaux and Maurice Lamy.

History and symptoms

Children with MPS VI, Maroteaux–Lamy syndrome, usually have normal intellectual development but share many of the physical symptoms found in Hurler syndrome

Hurler syndrome

Hurler syndrome, also known as mucopolysaccharidosis type I , Hurler's disease, also gargoylism, is a genetic disorder that results in the buildup of glycosaminoglycans due to a deficiency of alpha-L iduronidase, an enzyme responsible for the degradation of mucopolysaccharides in lysosomes...

. Caused by the deficient enzyme

Enzyme

Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...

 N-acetylgalactosamine 4-sulfatase, Maroteaux–Lamy syndrome has a variable spectrum of severe symptoms. Neurological complications include clouded cornea

Cornea

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...

s, deafness, thickening of the dura

Dura mater

The dura mater , or dura, is the outermost of the three layers of the meninges surrounding the brain and spinal cord. It is derived from Mesoderm. The other two meningeal layers are the pia mater and the arachnoid mater. The dura surrounds the brain and the spinal cord and is responsible for...

 (the membrane

Membrane

-In biology:* Biological membrane* Cell membrane, a biological type of Membrane ** Inner membrane** Outer membrane * The two fetal membranes** amnion** chorion* Basement membrane* Mucous membrane* Serous membrane...

 that surrounds and protects the brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 and spinal cord

Spinal cord

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

), and pain

Pain

Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...

 caused by compressed or traumatized nerve

Nerve

A peripheral nerve, or simply nerve, is an enclosed, cable-like bundle of peripheral axons . A nerve provides a common pathway for the electrochemical nerve impulses that are transmitted along each of the axons. Nerves are found only in the peripheral nervous system...

s and nerve root

Nerve root

A nerve root is the initial segment of a nerve leaving the central nervous system. Types include:* A cranial nerve root, the beginning of one of the twelve pairs leaving the central nervous system from the brain stem or the highest levels of the spinal cord;...

s.

Signs are revealed early in the affected child's life, with one of the first symptoms often being a significantly prolonged age of learning how to walk. By age 10 children have developed a shortened trunk, crouched stance, and restricted joint movement. In more severe cases, children also develop a protruding abdomen

Abdomen

In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...

 and forward-curving spine

Vertebral column

In human anatomy, the vertebral column is a column usually consisting of 24 articulating vertebrae, and 9 fused vertebrae in the sacrum and the coccyx. It is situated in the dorsal aspect of the torso, separated by intervertebral discs...

. Skeletal changes (particularly in the pelvic

Pelvis

In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...

 region) are progressive and limit movement. Many children also have umbilical hernia

Umbilical hernia

Congenital umbilical hernia is a congenital malformation, common in infants of African descent. Among adults, it is three times more common in women than in men; among children, the ratio is roughly equal...

 or inguinal hernia

Inguinal hernia

An inguinal hernia is a protrusion of abdominal-cavity contents through the inguinal canal. They are very common , and their repair is one of the most frequently performed surgical operations....

s. Nearly all children have some form of heart disease

Heart disease

Heart disease, cardiac disease or cardiopathy is an umbrella term for a variety of diseases affecting the heart. , it is the leading cause of death in the United States, England, Canada and Wales, accounting for 25.4% of the total deaths in the United States.-Types:-Coronary heart disease:Coronary...

, usually involving valve

Heart valve

A heart valve normally allows blood flow in only one direction through the heart. The four valves commonly represented in a mammalian heart determine the pathway of blood flow through the heart...

 dysfunction.
An enzyme replacement therapy

Enzyme replacement therapy

Enzyme replacement therapy is a medical treatment replacing an enzyme in patients in whom that particular enzyme is deficient or absent. Usually this is done by giving the patient an intravenous infusion containing the enzyme...

, galsulfase (Naglazyme), was tested on patients with MPS VI and was successful in that it improved growth and joint movement. An experiment was then carried out to see whether an injection of the missing enzyme into the hips would help the range of motion and pain. Costing $350,000 a year, Naglazyme is one of the world's most expensive drugs.

People with Maroteaux–Lamy syndrome

Perhaps the best known person living with Maroteaux-Lamy syndrome is YouTube sensation Keenan Cahill

Keenan Cahill

Keenan Cahill is a teenager from Elmhurst, Illinois whose lip-syncing of popular songs has brought his videos on YouTube to some of the most viewed online videos. Guest artists on his channel have included rapper 50 Cent in November 2010, David Guetta in January 2011, and Jersey Shore's Paul...

.