Defective CHSY1 does not transfer GalNAc to chondroitin

Stable Identifier
Reaction [transition]
Homo sapiens
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Chondroitin sulfate synthase 1 (CHSY1) (Kitagawa et al. 2001) possesses both beta-1,3-glucuronate (GlcA) and beta-1,4-N-acetylgalactosamine (GalNAc) transferase activity, added alternatingly the two building blocks GlcA and GalNAc to the growing chondroitin chain. Complete or almost complete loss of CHSY1 results in temtamy preaxial brachydactyly syndrome (TPBS; MIM:605282), an autosomal recessive characterized by limb malformations, short stature, and hearing loss. Mutations in CHSY1 leading to loss of function include E33Sfs*34, G19_L28del, P539R and Q69* (Temtamy et al. 1998, Li et al. 2010).

Literature References
PubMed ID Title Journal Year
21129728 Temtamy preaxial brachydactyly syndrome is caused by loss-of-function mutations in chondroitin synthase 1, a potential target of BMP signaling

Yigit, G, Aglan, M, Laue, K, Baessmann, I, Wakeling, EL, Topaloglu, AK, Temtamy, S, Hammerschmidt, M, Kotan, LD, Amr, K, Nürnberg, G, Pawlik, B, Hegele, RA, Wollnik, B, Canan, H, Lanktree, MB, Li, Y, Nürnberg, P, Quarrell, OW, May, KW, Yilmaz, M

Am J Hum Genet 2010
11514575 Molecular cloning and expression of a human chondroitin synthase

Uyama, T, Kitagawa, H, Sugahara, K

J Biol Chem 2001
9823490 A new multiple congenital anomaly, mental retardation syndrome with preaxial brachydactyly, hyperphalangism, deafness and orodental anomalies

Temtamy, SA, Ramzy, MI, Ismail, SI, Meguid, NA

Clin. Dysmorphol. 1998
Catalyst Activity

glucuronosyl-N-acetylgalactosaminyl-proteoglycan 4-beta-N-acetylgalactosaminyltransferase activity of CHSY1 mutants [Golgi membrane]

Normal reaction
Functional status

Loss of function of CHSY1 mutants [Golgi membrane]

Name Identifier Synonyms
brachydactyly DOID:0050581
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