Identification of two novel COL10A1 heterozygous mutations in two Chinese pedigrees with Schmid-type metaphyseal chondrodysplasia

Background: Schmid-type metaphyseal chondrodysplasia (MCDS) is an autosomal dominant disorder caused by COL10A1 mutations, which is characterized by short stature, waddling gait, coxa vara and bowing of the long bones. However, descriptions of the expressivity of MCDS are rare. Methods: Two probands and available family members affected with MCDS were subjected to clinical and radiological examination. Genomic DNA of all affected individuals was subjected to whole-exome sequencing, and candidate mutations were verified by Sanger sequencing in all available family members and in 250 healthy donors. A spatial model of the type X collagen (α1) C-terminal noncollagenous (NC1) domain was further constructed. Results: We found that the phenotype of affected family members exhibited incomplete dominance. Mutation analysis indicated that there were two novel heterozygous missense mutations, [c.1765T>A (p.Phe589Ile)] and [c.1846A>G (p.Lys616Glu)] in the COL10A1 gene in family 1 and 2, respectively. The two novel substitution sites were highly conserved and the mutations were predicted to be deleterious by in silico analysis. Furthermore, protein modeling revealed that the two substitutions were located in the NC1 domain of collagen X (α1), which potentially impacted the trimerization of collagen X (α1) and combination with molecules in the pericellular matrix. Conclusion: Two novel mutations were identified in the present study, which will facilitate diagnosis of MCDS and further expand the spectrum of the COL10A1 mutations associated with MCDS patients. In addition, our research revealed the phenomenon of incomplete dominance in MCDS.

Identification of two novel COL10A1 heterozygous mutations in two Chinese pedigrees with Schmid-type metaphyseal chondrodysplasia

Background: Schmid-type metaphyseal chondrodysplasia (MCDS) is an autosomal dominant disorder caused by COL10A1 mutations, which is characterized by short stature, waddling gait, coxa vara and bowing of the long bones. However, descriptions of the expressivity of MCDS are rare. Methods: Two probands and available family members affected with MCDS were subjected to clinical and radiological examination. Genomic DNA of all affected individuals was subjected to whole-exome sequencing, and candidate mutations were verified by Sanger sequencing in all available family members and in 250 healthy donors. A spatial model of the type X collagen (α1) C-terminal noncollagenous (NC1) domain was further constructed. Results: We found that the phenotype of affected family members exhibited incomplete dominance. Mutation analysis indicated that there were two novel heterozygous missense mutations, [c.1765T>A (p.Phe589Ile)] and [c.1846A>G (p.Lys616Glu)] in the COL10A1 gene in family 1 and 2, respectively. The two novel substitution sites were highly conserved and the mutations were predicted to be deleterious by in silico analysis. Furthermore, protein modeling revealed that the two substitutions were located in the NC1 domain of collagen X (α1), which potentially impacted the trimerization of collagen X (α1) and combination with molecules in the pericellular matrix. Conclusion: Two novel mutations were identified in the present study, which will facilitate diagnosis of MCDS and further expand the spectrum of the COL10A1 mutations associated with MCDS patients. In addition, our research revealed the phenomenon of incomplete dominance in MCDS.

Identification of two novel COL10A1 heterozygous mutations in two Chinese pedigrees with Schmid-type metaphyseal chondrodysplasia

Background: Schmid-type metaphyseal chondrodysplasia (MCDS) is an autosomal dominant disorder caused by COL10A1 mutations, which is characterized by short stature, waddling gait, coxa vara and bowing of the long bones. However, descriptions of the expressivity of MCDS are rare. Methods: Two probands and available family members affected with MCDS were subjected to clinical and radiological examination. Genomic DNA of all affected individuals was subjected to whole-exome sequencing, and candidate mutations were verified by Sanger sequencing in all available family members and in 250 healthy donors. A spatial model of the type X collagen (α1) C-terminal noncollagenous (NC1) domain was further constructed. Results: We found that the phenotype of affected family members exhibited irregular dominance. Mutation analysis indicated that there were two novel heterozygous missense mutations, [c.1765T>A (p.Phe589Ile)] and [c.1846A>G (p.Lys616Glu)] in the COL10A1 gene in family 1 and 2, respectively. The two novel substitution sites were highly conserved and the mutations were predicted to be deleterious by in silico analysis. Furthermore, protein modeling revealed that the two substitutions were located in the NC1 domain of collagen X (α1), which potentially impacted the trimerization of collagen X (α1) and combination with molecules in the pericellular matrix. Conclusion: Two novel mutations were identified in the present study, which will facilitate diagnosis of MCDS and further expand the spectrum of the COL10A1 mutations associated with MCDS patients. In addition, our research revealed the phenomenon of irregular dominance in MCDS.

Identification of two novel COL10A1 heterozygous mutations in two Chinese pedigrees with Schmid-type metaphyseal chondrodysplasia

Background: Schmid-type metaphyseal chondrodysplasia (MCDS) is an autosomal dominant disorder caused by COL10A1 mutations, which is characterized by short stature, waddling gait, coxa vara and bowing of the long bones. However, descriptions of the expressivity of MCDS are rare. Methods: Two probands and available family members affected with MCDS were subjected to clinical and radiological examination. Genomic DNA of all affected individuals was subjected to whole-exome sequencing, and candidate mutations were verified by Sanger sequencing in all available family members and in 250 normal control donors. A spatial model of the type X collagen (α1) C-terminal noncollagenous (NC1) domain was further constructed. Results: We found that the phenotype of affected family members exhibited irregular dominance. Mutation analysis indicated that there were two novel heterozygous missense mutations, [c.1765T>A (p.Phe589Ile)] and [c.1846A>G (p.Lys616Glu)] in the COL10A1 gene in family 1 and 2, respectively. The two novel substitution sites were highly conserved and the mutations were predicted to be deleterious by in silico analysis. Furthermore, protein modeling revealed that the two substitutions were located in the NC1 domain of collagen X (α1), which potentially impacted the trimerization of collagen X (α1) and combination with molecules in the pericellular matrix. Conclusion: Two novel mutations were identified in the present study, which will facilitate diagnosis of MCDS and further expand the spectrum of the COL10A1 mutations associated with MCDS patients. In addition, our research revealed the phenomenon of irregular dominance in MCDS.

Exome sequencing identified two novel COL10A1 heterozygous mutations in two irregular dominance Chinese pedigrees with Schmid-type metaphyseal chondrodysplasia

Background Schmid-type metaphyseal chondrodysplasia (MCDS) is an autosomal dominant disorder caused by COL10A1 mutations, which is characterized by short stature, waddling gait, coxa vara and bowing of the long bones. However, the research about unusual phenotype features of MCDS is rare. Methods Two probands and available family members affected with MCDS were subjected to clinical and radiological examination. Genomic DNA of all affected individuals underwent whole-exome sequencing, and candidate mutations were verified by Sanger sequencing in all available family members and 250 donors. Then the spatial model of type X collagen (α1) C-terminal noncollagenous (NC1) domain was further constructed. Results We found that the affected family members exhibited evident irregular dominance. Mutation analysis indicated that there were two novel heterozygous missense mutations [c.1765T>A (p.Phe589Ile)] and [c.1846A>G (p.Lys616Glu)] in the COL10A1 gene in family 1 and 2, respectively. The two novel substitution sites were highly conserved and the mutations were predicted to be remarkably deleterious in silico analysis. Furthermore, protein modeling revealed that the two substitutions located in the NC1 domain of collagen X (α1), which potentially impacted the trimerization of collagen X (α1) and combination with molecules in pericellular matrix. Conclusion Two novel mutations were identified in the present study, which facilitated to diagnose MCDS and further expanded the spectrum of the COL10A1 mutations associated with MCDS patients. In addition, our research preliminarily elaborated the phenotype features and heredity characteristics of MCDS based on the two Chinese pedigrees.

Skeletal Mineralization in Association with Type X Collagen Expression Is an Ancestral Feature for Jawed Vertebrates

In order to characterize the molecular bases of mineralizing cell evolution, we targeted type X collagen, a nonfibrillar network forming collagen encoded by the Col10a1 gene. It is involved in the process of endochondral ossification in ray-finned fishes and tetrapods (Osteichthyes), but until now unknown in cartilaginous fishes (Chondrichthyes). We show that holocephalans and elasmobranchs have respectively five and six tandemly duplicated Col10a1 gene copies that display conserved genomic synteny with osteichthyan Col10a1 genes. All Col10a1 genes in the catshark Scyliorhinus canicula are expressed in ameloblasts and/or odontoblasts of teeth and scales, during the stages of extracellular matrix protein secretion and mineralization. Only one duplicate is expressed in the endoskeletal (vertebral) mineralizing tissues. We also show that the expression of type X collagen is present in teeth of two osteichthyans, the zebrafish Danio rerio and the western clawed frog Xenopus tropicalis, indicating an ancestral jawed vertebrate involvement of type X collagen in odontode formation. Our findings push the origin of Col10a1 gene prior to the divergence of osteichthyans and chondrichthyans, and demonstrate its ancestral association with mineralization of both the odontode skeleton and the endoskeleton.