 Specific investigations of this gene have identified 78del85 and 965del59 mutations in a homozygous state, while some mutations could not be identified due to no PDHX mRNA being expressed in the individuals.In other cases, it has been reported that an entire exon, exon 10, was removed due to a gross deletion mutation; the mechanism for this has been theorized to be a mispairing, because there is an exact direct repeat, CCACTG, within the gene.Other large deletions (over 3900 bp) have been reported.