Exons 10, 11, and 12 (and the introns between) were replaced with the corresponding cDNA without the last 30 nucleotides of exon 11 and the first 24 nucleotides of exon 12 to bring the last codon of mature lamin A adjacent to the prelamin A stop codon. This allele is predicted to produce only the mature lamin A isoform. (J:165928)