Key Words
Apert syndrome - One of a group of genetic disorders, called acrocephalosyndactyly, characterized by malformations of the skull, face, hands, and feet. Apert syndrome is an autosomonal dominant trait due to a mutation in a gene called FGFR2 (fibroblast growth factor receptor 2).
Beta blockers - A class of medications also known as beta-andrenergic blockers that affect the body's response to certain nerve impulses. This, in turn, decreases the rate and force of the heart's contractions, which lowers blood pressure and reduces the heart's demand for oxygen. In addition to treating high blood pressure, beta blockers may be used for angina, and to prevent heart attacks, migraine headaches, and glaucoma.
Carrier - A person who carries a gene for a recessive genetic disorder. The person has the potential to pass the disorder on to his or her child, but is not personally affected by the disorder.
Collagen - The principal protein of the skin, bones, cartilage, tendons, and other connective tissues.
Chondrodysplasias - Once referred to as dwarfism. A group of genetic disorders, often caused by a single gene variation that affects the structure or metabolism of the bone, cartilage, or connective tissue.
Cutis laxa - Latin for loose or lax skin, cutis laxa refers to an extremely rare connective tissue disorder in which the skin lacks elasticity and hangs in loose folds. Caused by underlying genetic defects in connective tissue structure, the disorder can also result in serious problems with vocal cords, bones, cartilage, blood vessels, and vital internal organs.
Dominant - A genetic trait (or genetically transmitted disorder) that is evident when only one copy of the gene for that trait is present. Most dominant traits are due to genes on the autosomes (nonsex chromosomes). They affect males and females equally.
Dural ectasia - An enlargement of the dura, a primary membrane of connective tissue that covers the spine and contains the spinal fluid. Common in people with Marfan syndrome, dural ectasia occurs mainly in the lower spine and can cause low back pain, abdominal pain, headaches, leg pain, and perineal pain and numbness.
Ehlers-Danlos syndrome - A heritable connective tissue disease characterized by easy bruising, joint laxity (the ability to bend beyond normal range of motion), lax skin, and tissue weakness.
Epidermolysis bullosa - A potentially disabling, disfiguring, and sometimes lethal connective tissue disorder caused by defects of several proteins in the skin, resulting in skin blistering. Some forms of the disease may involve the gastrointestinal tract, the pulmonary system, muscles, or the bladder.
Glycoprotein - An organic compound composed of a protein and a carbohydrate joined together. In the body, these compounds have many uses and comprise many of the proteins released by cells into the blood and other fluids.
Heritable - Capable of being transmitted from parent to child through genes.
Homocystinuria - A genetically transmitted disease in which an enzyme deficiency permits the buildup of the amino acid homocyteine. The result, if not treated, can be mental retardation, blood vessel disease, and atherosclerosis (hardening of the arteries).
Mutations - Changes in genes that can occur randomly or as a result of some factor in the environment.
Marfan syndrome - A heritable disorder of connective tissue resulting from mutations in the gene that specifies the genetic code for fibrillin-1, a protein important to connective tissue. The disorder is characterized by excessively long leg bones and long “spider-like” fingers. Other problems include skeletal malformations, abnormal position of the lens of the eye, and enlargement at the beginning part of the aorta, the major vessel carrying blood away from the heart. If left untreated, an enlarged aorta can lead to hemorrhage and even death.
Nail-patella syndrome (NPS) - A rare genetic disorder that causes abnormalities of bones, joints, fingernails, and kidneys. NPS is commonly characterized by absent or underdeveloped kneecaps and thumbnails. It is estimated to occur in one in 50,000 newborns.
Osteogenesis imperfecta - A condition that results from mutation in two genes that make type I collagen, a protein important to bones and teeth. These mutations cause the body to either make too little collagen or poor-quality collagen. The result includes bones that fracture easily, low muscle mass, and joints and ligaments that move beyond their intended range of motion.
Pfeiffer syndrome - Also called type V acrocephalosyndactyly, Pfeiffer syndrome is one of a group of genetic disorders characterized by malformations of the skull, face, hands, and feet. Like the more common Apert syndrome, Pfeiffer syndrome is caused by a mutation in the FGFR2 (fibroblast growth factor receptor 2) gene.
Proteoglycans - A class of glycoproteins that perform various functions and serve as the “filler” substance between the cells. An inability to break down proteoglycans is characteristic of a series of genetic disorders called mucopolysaccharidoses.
Pseudoxanthoma elasticum (PXE) - A rare disorder of degeneration of the elastic fibers with tiny areas of calcification in the skin, the back of the eyes (retinae), and the blood vessels. PXE typically causes skin abnormalities, eye abnormalities that can lead to blindness, atherosclerosis (hardening of the arteries), mitral valve prolapse, and fragile blood vessels that can lead to problems with circulation and abnormal bleeding into internal organs, including the bowel. PXE is inherited either as an autosomal recessive or as an autosomal dominant trait.
Recessive - A genetic trait or disorder that is usually expressed when only two copies of a gene for that trait, one from each parent, are present.
Scoliosis - A lateral side-to-side curvature of the spine. In most cases the cause is not known, but it may be more common in people who have a family history of the condition. Treatment can include braces, physical therapy, and, in some cases, surgery.