Figure 4

Repartition of the various types of mutations identified in the COL6A1, COL6A2 and COL6A3 genes. This schematic reflects, to the best of our ability, the distribution of 258 allelic mutations (98 on COL6A1, 113 on COL6A2 and 47 on COL6A3). Dominant de novo mutations represent 67% of the missense mutations, affecting glycine residues in the TH domains (Gly in TH), 57% of small deletions (< 5 amino acids) and 44% of splice-site mutations leading to in-frame exon skipping, whereas 97% of mutations leading to premature termination codons (PTCs) are familial (recessive or dominant).