Description
Spondyloepiphyseal dysplasia (SED) congenita is a disorder of bone development that causes short stature with a particularly short torso and short arms and legs. The parts of the body are not proportional to one another (disproportionate short stature) in people with this condition. Affected individuals typically have hands and feet that are of average size. SED congenita affects the bones of the spine (spondylo-) and the ends (epiphyses) of the long bones in the arms and legs. People with this condition also have problems with vision and hearing. The word "congenita" indicates that the condition is often noticeable at birth. The signs and symptoms of SED congenita can vary among affected individuals.
People with SED congenita have an adult height that ranges from 3 feet to almost 5 feet. Affected individuals may develop abnormal curvature of the spine (scoliosis or kyphosis), which can worsen during childhood. Instability of the spinal bones (vertebrae) in the neck can cause these bones to shift, which increases the risk of damage to the spinal cord.
Other skeletal issues in individuals with SED congenita can include flattened vertebrae (platyspondyly), an abnormality of the hip joint that causes the upper leg bones to turn inward (coxa vara), and inward- and upward-turning feet (clubfoot). Arthritis and decreased joint mobility often develop early in life. An abnormally short, broad, and barrel-shaped chest can cause problems with breathing. People with SED congenita may also have breathing problems due to weakness of the windpipe.
SED congenita often causes mild differences in facial features such as underdeveloped cheek bones (malar hypoplasia). Some affected individuals have a particular group of physical features called Pierre Robin sequence, which includes an opening in the roof of the mouth (cleft palate), a tongue that is placed further back than normal (glossoptosis), and a small lower jaw (micrognathia). Severe nearsightedness (high myopia) is common in SED congenita, as are other eye problems that can impair vision such as a tearing of the light-sensitive tissue at the back of the eye (retinal detachment). Some people with SED congenita have hearing loss.
Some disorders, such as spondyloepiphyseal dysplasia with premature-onset arthrosis and Namaqualand type hip dysplasia, are similar to SED congenita but have milder signs and symptoms. These milder conditions were once thought to be separate disorders, but they are now considered to be part of SED congenita. People with these disorders typically have joint pain and stiffness, which can restrict movement. Symptoms can begin in childhood and often worsen over time.
Frequency
Though it is one of the more common skeletal dysplasias, SED congenita is rare. The exact prevalence is unknown.
Causes
SED congenita is caused by variants (also called mutations) in the COL2A1 gene. This gene provides instructions for making a protein that forms type II collagen. This type of collagen is found in the clear gel that fills the eyeball (the vitreous) and in cartilage. Cartilage is a tough, flexible tissue that makes up much of the skeleton during early development; most cartilage is later converted to bone. Type II collagen is essential for the normal growth and development of bones and other connective tissues.
The variants in the COL2A1 gene that cause SED congenita interfere with the assembly of type II collagen molecules, which prevents bones and other connective tissues from developing properly. This impaired bone development leads to short stature and the other characteristic features of SED congenita.
Inheritance
Typically, SED congenita is inherited in an autosomal dominant pattern, which means one copy of the altered COL2A1 gene in each cell is sufficient to cause the disorder. Many cases of this condition are the result of a new (de novo) variant in the COL2A1 gene that occurs during the formation of reproductive cells (eggs or sperm) in an affected individual's parent or during early embryonic development. These affected individuals have no history of the disorder in their family.
In rare cases, SED congenita is inherited in an autosomal recessive pattern, which means both copies of the COL2A1 gene in each cell must have a variant to cause the disorder. The parents of an individual with an autosomal recessive condition each carry one copy of the altered gene, but they typically do not show signs and symptoms of the condition.
Other Names for This Condition
- SED congenita
- SED, congenital type
- SEDc
- SEDC
- Spondyloepiphyseal dysplasia congenita (SEDC), COL2A1-related
- Spondyloepiphyseal dysplasia, congenital type
Additional Information & Resources
Genetic Testing Information
Genetic and Rare Diseases Information Center
Patient Support and Advocacy Resources
Clinical Trials
Catalog of Genes and Diseases from OMIM
Scientific Articles on PubMed
References
- Agenbag G, Vorster A, Julius S, Ramesar R, Beighton P. Namaqualand hip dysplasia in South Africa: The molecular determinant elucidated. S Afr Med J. 2020 Dec 14;111(1):57-60. doi: 10.7196/SAMJ.2020.v111i1.14561. Citation on PubMed
- Barat-Houari M, Baujat G, Tran Mau Them F, Fabre A, Genevieve D, Touitou I. Confirmation of autosomal recessive inheritance of COL2A1 mutations in spondyloepiphyseal dysplasia congenita: Lessons for genetic counseling. Am J Med Genet A. 2016 Jan;170A(1):263-5. doi: 10.1002/ajmg.a.37374. Epub 2015 Sep 11. No abstract available. Citation on PubMed
- Dahiya R, Cleveland S, Megerian CA. Spondyloepiphyseal dysplasia congenita associated with conductive hearing loss. Ear Nose Throat J. 2000 Mar;79(3):178-82. Citation on PubMed
- Gregersen PA, Savarirayan R. Type II Collagen Disorders Overview. 2019 Apr 25 [updated 2024 Oct 24]. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. Available from http://www.ncbi.nlm.nih.gov/books/NBK540447/ Citation on PubMed
- Silveira KC, Bonadia LC, Superti-Furga A, Bertola DR, Jorge AA, Cavalcanti DP. Six additional cases of SEDC due to the same and recurrent R989C mutation in the COL2A1 gene--the clinical and radiological follow-up. Am J Med Genet A. 2015 Apr;167A(4):894-901. doi: 10.1002/ajmg.a.36954. Epub 2015 Mar 3. No abstract available. Citation on PubMed
- Spranger J, Winterpacht A, Zabel B. The type II collagenopathies: a spectrum of chondrodysplasias. Eur J Pediatr. 1994 Feb;153(2):56-65. doi: 10.1007/BF01959208. Citation on PubMed
- Terhal PA, Nievelstein RJ, Verver EJ, Topsakal V, van Dommelen P, Hoornaert K, Le Merrer M, Zankl A, Simon ME, Smithson SF, Marcelis C, Kerr B, Clayton-Smith J, Kinning E, Mansour S, Elmslie F, Goodwin L, van der Hout AH, Veenstra-Knol HE, Herkert JC, Lund AM, Hennekam RC, Megarbane A, Lees MM, Wilson LC, Male A, Hurst J, Alanay Y, Anneren G, Betz RC, Bongers EM, Cormier-Daire V, Dieux A, David A, Elting MW, van den Ende J, Green A, van Hagen JM, Hertel NT, Holder-Espinasse M, den Hollander N, Homfray T, Hove HD, Price S, Raas-Rothschild A, Rohrbach M, Schroeter B, Suri M, Thompson EM, Tobias ES, Toutain A, Vreeburg M, Wakeling E, Knoers NV, Coucke P, Mortier GR. A study of the clinical and radiological features in a cohort of 93 patients with a COL2A1 mutation causing spondyloepiphyseal dysplasia congenita or a related phenotype. Am J Med Genet A. 2015 Mar;167A(3):461-75. doi: 10.1002/ajmg.a.36922. Epub 2015 Jan 21. Citation on PubMed
- Terhal PA, van Dommelen P, Le Merrer M, Zankl A, Simon ME, Smithson SF, Marcelis C, Kerr B, Kinning E, Mansour S, Hennekam RC, van der Hout AH, Cormier-Daire V, Lund AM, Goodwin L, Megarbane A, Lees M, Betz RC, Tobias ES, Coucke P, Mortier GR. Mutation-based growth charts for SEDC and other COL2A1 related dysplasias. Am J Med Genet C Semin Med Genet. 2012 Aug 15;160C(3):205-16. doi: 10.1002/ajmg.c.31332. Epub 2012 Jul 12. Citation on PubMed
- Unger S, Ferreira CR, Mortier GR, Ali H, Bertola DR, Calder A, Cohn DH, Cormier-Daire V, Girisha KM, Hall C, Krakow D, Makitie O, Mundlos S, Nishimura G, Robertson SP, Savarirayan R, Sillence D, Simon M, Sutton VR, Warman ML, Superti-Furga A. Nosology of genetic skeletal disorders: 2023 revision. Am J Med Genet A. 2023 May;191(5):1164-1209. doi: 10.1002/ajmg.a.63132. Epub 2023 Feb 13. Citation on PubMed
- Xia X, Cui Y, Huang Y, Pan L, Wu Y, Zhang P, Jin B. A first familial G504S mutation of COL2A1 gene results in distinctive spondyloepiphyseal dysplasia congenita. Clin Chim Acta. 2007 Jul;382(1-2):148-50. doi: 10.1016/j.cca.2007.04.005. Epub 2007 Apr 14. No abstract available. Citation on PubMed
- Zhang Z, He JW, Fu WZ, Zhang CQ, Zhang ZL. Identification of three novel mutations in the COL2A1 gene in four unrelated Chinese families with spondyloepiphyseal dysplasia congenita. Biochem Biophys Res Commun. 2011 Oct 7;413(4):504-8. doi: 10.1016/j.bbrc.2011.08.090. Epub 2011 Sep 6. Citation on PubMed
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