Within this duplication resides the above-mentioned developmental gene EXOC6B. While the above EXOC6B-associated spondyloepimetaphyseal dysplasia with joint laxity, type 3 does not present with any visceral organ affection, the findings in individual 5 and in the two brothers 6 and 7 suggests a possible involvement of EXOC6B or the respective genomic region in ARM formation. This evidence concerns the gene EXOC6B and spondyloepimetaphyseal dysplasia, matrilin-3 type.