This mutation was induced by the insertion of an early transposon II-ß into intron 8 of the gene locus. The 5,543-bp ETn II-ß was integrated into intron 8, 203 bp away from the initial nucleotide of intron 8; it was flanked by a duplicated 6-bp repeat (ACTAGG) that originated from genomic sequence. 183-bp of this insertion acted as a pseudo exon by being transcribed in-frame, which disrupted the normal coding sequence for the extracellular cadherin repeat 3 (EC3) domain of the gene product.