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Purpose: To identify potential disease-causing mutation in the COL2A1 gene in a Chinese family with autosomal dominant spondyloepiphyseal dysplasia congenita (SEDC) and to analyze the phenotype-genotype correlation. Methods: Complete physical and radiographic examinations of four affected individuals from SEDC family were conducted. Genomic DNA were isolated from peripheral blood leukocytes. All 54 exons and exon-intron boundaries of the COL2A1 gene were amplified by polymerase chain reaction (PCR) and bidirectionally sequenced. Results: All four affected individuals were found carried a novel missense mutation of c.2224G>A (p.Gly687Ser) in COL2A1, while normal members of the family and 50 healthy controls did not have this mutation. Protein prediction of missense mutation by polyphen-2 and SIFT software and mutation taster indicated severe damage to the function. Conclusions: c.2224G>A (p.Gly687Ser) is a novel mutation of COL2A1 associated with spondyloepiphyseal dysplasia congenital. There are heterozygous of phenotype for the mutation in members of the pedigree analyzed. Onset becomes more earlier and severe with each successive generation. [ABSTRACT FROM AUTHOR]

Long-term treatment with the ghrelin receptor antagonist [d-Lys3]-GHRP-6 does not improve glucose homeostasis in nonobese diabetic MKR mice. Am J Physiol Regul Integr Comp Physiol 314: R71-R83, 2018. First published September 13, 2017; doi: 10.1152/ajpregu.00157.2017 .-Ghrelin secretion has been associated with increased caloric intake and adiposity. The expressions of ghrelin and its receptor (GHS-R1a) in the pancreas has raised the interest about the role of ghrelin in glucose homeostasis. Most of the studies showed that ghrelin promoted hyperglycemia and inhibited insulin secretion. This raised the interest in using GHS-R1a antagonists as therapeutic targets for type 2 diabetes. Available data of GHS-R antagonists are on a short-term basis. Moreover, the complexity of GHS-R1a signaling makes it difficult to understand the mechanism of action of GHS-R1a antagonists. This study examined the possible effects of long-term treatment with a GHS-R1a antagonist, [d-Lys3]-growth hormone-releasing peptide (GHRP)-6, on glucose homeostasis, food intake, and indirect calorimetric parameters in nonobese diabetic MKR mice. Our results showed that [d-Lys3]-GHRP-6 (200 nmol/mouse) reduced pulsatile growth hormone secretion and body fat mass as expected but worsened glucose and insulin intolerances and increased cumulative food intake unexpectedly. In addition, a significant increase in blood glucose and decreases in plasma insulin and C-peptide levels were observed in MKR mice following long-term [d-Lys3]-GHRP-6 treatment, suggesting a direct inhibition of insulin secretion. Immunofluorescence staining of pancreatic islets showed a proportional increase in somatostatin-positive cells and a decrease in insulin-positive cells in [d-Lys3]-GHRP-6-treated mice. Furthermore, [d-Lys3]-GHRP-6 stimulated food intake on long-term treatment via reduction of proopiomelanocortin gene expression and antagonized GH secretion via reduced growth hormone-releasing hormone gene expression in hypothalamus. These results demonstrate that [d-Lys3]-GHRP-6 is not completely opposite to ghrelin and may not be a treatment option for type 2 diabetes.

Objective: To identify potential disease-causing mutation in the COL2A1 gene in a Chinese family affected with autosomal dominant spondyloepiphyseal dysplasia congenita (SEDC; OMIM 183900) and to analyze the phenotype-genotype correlation., Methods: Complete physical, and radiographic examinations of 4 affected individuals from the family were conducted. Genomic DNA was isolated from peripheral blood leukocytes. Whole-exome sequencing was performed using a HiSeq2000 sequencer. All 54 exons and exon-intron boundaries of the COL2A1 gene were amplified by polymerase chain reaction (PCR) and bidirectionally sequenced., Results: All of the 4 individuals were found to carry a novel missense mutation of c.2224G>A (p.Gly687Ser) in the COL2A1 gene, while the same mutation was not found in the normal members of the family and 50 healthy controls. Protein prediction of missense mutation by Polyphen-2 and SIFT software indicated severe damage to the function., Conclusion: The mutation c.2224G>A (p.Gly687Ser) of the COL2A1 gene is responsible for this family. There are heterozygous of phenotype for the mutation.