GAN mutations in GAN fibroblasts. (A) Sequencing of the 1.8-kb RT-PCR product from MCH070 (wild-type) and WG0791 (GAN) cells. The WG0791 product contains an A→T missense mutation. The affected codon is underlined. (B) Sequencing of the 1.7-kb RT-PCR product from WG0791 (GAN) and the 1.8-kb product from MCH070 (wild-type) cells. GAN exon 2 is skipped in the 1.7-kb WG0791 product, resulting in an out-of-frame premature stop codon (*). (C) Sequencing of the RT-PCR products from MCH070 (wild-type) and WG0321 (GAN) cells. The WG0321 product includes part of intron 9. (D) Schematic representation of the GAN mutations in WG0321 and WG0791 patients. Because of a 9.3-kb deletion in the WG0321 allele, a portion of intron 9 is included in the mRNA (gray box). The intronic mutation in WG0791 is indicated with an arrowhead. The positions of the RT-PCR primers used to amplify GAN cDNA are also shown (arrows).