Crouzonodermoskeletal Syndrome
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Crouzonodermoskeletal syndrome is a disorder characterized by the premature joining of certain
bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...
s of the
skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...
(
craniosynostosis Craniosynostosis is a condition in which one or more of the fibrous sutures in a young infant's skull prematurely fuses by turning into bone (ossification), thereby changing the growth pattern of the skull. Because the skull cannot expand perpe ...
) during development and a skin condition called
acanthosis nigricans Acanthosis nigricans is a medical sign characterised by 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 armpits, groin, navel, foreh ...
. Some of the signs and symptoms of Crouzonodermoskeletal syndrome are similar to those seen with
Crouzon syndrome Crouzon syndrome is an autosomal dominant genetic disorder known as a branchial arch syndrome. Specifically, this syndrome affects the first branchial (or pharyngeal) arch, which is the precursor of the maxilla and mandible. Because the branchia ...
. 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 is an eye disorder in which the eyes do not properly align with each other when looking at an object. The eye that is pointed at an object can alternate. The condition may be present occasionally or constantly. If present during a ...
); 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 (
vertebra Each vertebra (: vertebrae) is an irregular bone with a complex structure composed of bone and some hyaline cartilage, that make up the vertebral column or spine, of vertebrates. The proportions of the vertebrae differ according to their spina ...
e). Noncancerous growths called
cementoma Cementoma is an odontogenic tumor of cementum. It is usually observed as a benign spherical mass of hard tissue fused to the root of a tooth. It is found most commonly in the mandible in the region of the lower molar teeth, occurring between th ...
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
FGFR3 Fibroblast growth factor receptor 3 (FGFR-3) is a protein that in humans is encoded by the ''FGFR3'' gene. FGFR3 has also been designated as CD333 (cluster of differentiation 333). The gene, which is located on chromosome 4, location p16.3, is e ...
gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
cause Crouzonodermoskeletal syndrome. The
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
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.


Diagnosis


Treatment


References

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External links

* {{Medical resources , ICD10 = Q75.1 , ICD9 = , ICDO = , OMIM = 612247 , DiseasesDB = , MedlinePlus = , eMedicineSubj = , eMedicineTopic = , MeSH = , GeneReviewsNBK = , GeneReviewsName = , Orphanet = 93262 , MeshID = C567382 , SNOMED CT = 702361006 Congenital disorders of musculoskeletal system Syndromes