Lesch-Nyhan Syndrome: is a rare, inherited disorder caused by a deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase. The lack of HPRT causes a build-up of uric acid in all body fluids, and leads to symptoms such as severe gout, poor muscle control, and moderate retardation, which appear in the first year of life. Abnormally high uric acid levels can cause sodium urate crystals to form in the joints, kidneys, central nervous system, and other tissues of the body, leading to gout-like swelling in the joints and severe kidney problems.
Linear Scleroderma: is a line of thickened skin which can affect the bones and muscles underneath it, thus limiting the motion of the affected joints and muscles. It most often occurs in the arms, legs, or forehead, and may occur in more than one area.
Lyme Disease: is a bacterial illness caused by a bacterium called a "spirochete." Lyme disease is spread by ticks when they bite the skin permitting the bacterium to infect the body. Lyme disease can cause abnormalities in the skin, joints, heart and nervous system. When joints are affected, arthritis, or inflammation in the joints, begins with swelling, stiffness, and pain. Usually, only one or a few joints become affected, most commonly the knees. The arthritis of Lyme disease can look like many other types of arthritis and can become chronic.
Marfan's Syndrome: is a heritable condition that affects the connective tissue. In the Marfan syndrome, the connective tissue is defective and does not act as it should. Because connective tissue is found throughout the body, the Marfan syndrome can affect many body systems, including the skeleton, eyes, heart and blood vessels, nervous system, skin and lungs.
Medial Plica Syndrome: is a constellation of signs and symptoms that occur secondary to injury or overuse. An otherwise normal structure, a plica can be a significant source of pain in the back of the knee. Once swelling sets in, the normal plical tissue may enlarge and become problematic.
Mixed Connective Tissue Disease: describes what may be an overlapping group of connective tissue disorders that cannot be diagnosed in more specific terms. These disorders include systemic lupus erythematosus, polymyositis, and scleroderma. Individuals with MCTD have symptoms of each of these disorders including arthritic, cardiac, pulmonary and skin manifestations; kidney disease; muscle weakness; and dysfunction of the esophagus. The exact cause of mixed connective tissue disease is unknown.
Mixed Cryoglobulinemia: is a chronic autoimmune disorder that is almost always associated with chronic liver inflammation due to hepatitis C virus infection. It is believed to develop when chronic liver inflammation causes B cells to grow out of control and produce excessive amounts of antibodies, especially anti-IgG antibodies known as rheumatoid factors.
Mucopolysaccharidosis: are a group of inherited lysosomal storage disorders, meaning conditions in which cells cannot adequately digest and eliminate waste. MPSs are caused by a deficiency of specific lysosomal enzymes required for the degradation of glycosaminoglycans.
Multiple Epiphyseal Dysplasia: is a rare inherited spectrum of disorders characterized by malformation of the "growing portion" or head of the long bones. Affected individuals may have an abnormally short thighbone, unusually short hands and fingers, mild short stature, a waddling gait, and/or pain in the hips and knees. In some cases, painful swelling and inflammation of certain joints may be present as early as five years of age.
Myofascial Pain Syndrome:is a painful musculoskeletal condition, a common cause of musculoskeletal pain. MPS is characterized by the development of Myofascial trigger points that are locally tender when active, and refer pain through specific patterns to other areas of the body. A trigger point or sensitive, painful area in the muscle or the junction of the muscle and fascia develops due to any number of causes. Trigger points are usually associated with a taut band, a ropey thickening of the muscle tissue. Typically a trigger point, when pressed upon, will cause the pain to be felt elsewhere.
Neonatal Lupus:is a rare autoimmune disorder that is present at birth. Affected infants often develop a characteristic red rash or skin eruption. In addition, infants with neonatal lupus may develop liver disease, a heart condition known as congenital heart block, and/or low numbers of circulating blood platelets that assist in blood clotting functions. The symptoms associated with neonatal lupus, with the exception of congenital heart block, usually resolve within the first several months of life.