COL9A1 and multiple epiphyseal dysplasia: The current study assessed in the order of the coding sequences and flanking sequences of five genes: COMP (exons 8–19), MATN3 (exon 2), COL9A2 (exon 3), COL9A3 (exon 3), COL9A1 (exon 8) associated with MED by Sanger sequencing, and characterized the associated clinical features.