Conflicting reports exist on the nature of the molecular mutation in this gene. According to one report, this mutation is a deletion of exons 4 and 5, resulting in the absence of 380 bp from the transcript. The predicted protein expressed from this allele would lack 127 amino acids including sequences corresponding to the DNA binding domain. The deletion also introduces a frameshift and creates a premature stop codon. A second report states that an antisense insertion of L1 into exon5 prevents the excision of intron 5 and blocks the release of precursor from its site of synthesis. For details, see the associated references.