Crouzonodermoskeletal syndrome
Encyclopedia
Crouzonodermoskeletal syndrome is a disorder characterized by the premature joining of certain bone
s of the skull
(craniosynostosis
) during development and a skin condition called acanthosis nigricans
.
Some of the signs and symptoms of Crouzonodermoskeletal syndrome are similar to those seen with Crouzon syndrome
. They include prematurely fused skull bones, which affect the shape of the head and face; wide-set, bulging eyes due to shallow eye sockets; eyes that do not point in the same direction (strabismus
); a small, beaked nose; and an underdeveloped upper jaw. People with these conditions are generally of normal intelligence.
Several features distinguish Crouzonodermoskeletal syndrome from Crouzon syndrome. People with Crouzonodermoskeletal syndrome have acanthosis nigricans, a skin condition characterized by thick, dark, velvety skin in body folds and creases, including the neck and underarms. In addition, subtle changes may be seen in the bones of the spine (vertebrae). Noncancerous growths called cementoma
s may develop in the jaw during young adulthood.
Crouzonodermoskeletal syndrome is rare; the condition is seen in about 1 per million people.
gene
cause Crouzonodermoskeletal syndrome. The protein
made by the FGFR3 gene is a receptor that plays a role in the development and maintenance of bone and brain tissue. Researchers do not know how a mutation in FGFR3 leads to the characteristic features of this disorder, but changes in the receptor appear to disrupt the normal development of bones in the skull and affect skin pigmentation.
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family.
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
s of the skull
Human skull
The human skull is a bony structure, skeleton, that is in the human head and which supports the structures of the face and forms a cavity for the brain.In humans, the adult skull is normally made up of 22 bones...
(craniosynostosis
Craniosynostosis
Craniosynostosis is a condition in which one or more of the fibrous sutures in an infant skull prematurely fuses by ossification, thereby changing the growth pattern of the skull...
) during development and a skin condition called acanthosis nigricans
Acanthosis nigricans
Acanthosis nigricans is a brown to black, poorly defined, velvety hyperpigmentation of the skin. It is usually found in body folds, such as the posterior and lateral folds of the neck, the axilla, groin, umbilicus, forehead, and other areas.-Causes:...
.
Some of the signs and symptoms of Crouzonodermoskeletal syndrome are similar to those seen with Crouzon syndrome
Crouzon syndrome
Crouzon syndrome is a genetic disorder known as a branchial arch syndrome. Specifically, this syndrome affects the first branchial arch, which is the precursor of the maxilla and mandible...
. They include prematurely fused skull bones, which affect the shape of the head and face; wide-set, bulging eyes due to shallow eye sockets; eyes that do not point in the same direction (strabismus
Strabismus
Strabismus is a condition in which the eyes are not properly aligned with each other. It typically involves a lack of coordination between the extraocular muscles, which prevents bringing the gaze of each eye to the same point in space and preventing proper binocular vision, which may adversely...
); a small, beaked nose; and an underdeveloped upper jaw. People with these conditions are generally of normal intelligence.
Several features distinguish Crouzonodermoskeletal syndrome from Crouzon syndrome. People with Crouzonodermoskeletal syndrome have acanthosis nigricans, a skin condition characterized by thick, dark, velvety skin in body folds and creases, including the neck and underarms. In addition, subtle changes may be seen in the bones of the spine (vertebrae). Noncancerous growths called cementoma
Cementoma
Cementoma is an odontogenic tumor of cementum.It occurs in usually after root development is finished but before the age of 25. It is found most commonly in the mandible in the region of the lower molar teeth. It causes distortion of its sourrounding areas but is a usually painless growth , at...
s may develop in the jaw during young adulthood.
Crouzonodermoskeletal syndrome is rare; the condition is seen in about 1 per million people.
Genetics
Mutations in the FGFR3FGFR3
Fibroblast growth factor receptor 3 is a protein that in humans is encoded by the FGFR3 gene. FGFR3 has also been designated as CD333 .-Structure and function:-Disease linkage:...
gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
cause Crouzonodermoskeletal syndrome. The protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
made by the FGFR3 gene is a receptor that plays a role in the development and maintenance of bone and brain tissue. Researchers do not know how a mutation in FGFR3 leads to the characteristic features of this disorder, but changes in the receptor appear to disrupt the normal development of bones in the skull and affect skin pigmentation.
This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.
In some cases, an affected person inherits the mutation from one affected parent. Other cases may result from new mutations in the gene. These cases occur in people with no history of the disorder in their family.