Genetic analysis of the ABCA1 gene. A PCR amplification of the ABCA1 gene region spanning from exon 31 to exon 35 in patient # Mo.4 The figure shows the agarose gel electrophoresis of the PCR fragments obtained in a control subject (lane 1) and in the proband #Mo-4 (lane 2) respectively. Molecular size markers are shown in lane 3. The size of the band seen in lane 2 is consistent with a deletion of ~ 3.5 Kb. B Deletion of exon 32-34 of ABCA1 gene found in patient #Mo-4. The upper panel shows Alu sequences located in intron 31 and intron 34. The Alu Sx in intron 31 and Alu Sq2 sequences in intron 34 are involved in the recombination event resulting in the deletion. The lower panel shows the nucleotide sequence of the genomic breakpoint indicating that the 3’ half of intron 31 is followed by the 5’ half of intron 34. The boxed nucleotide sequence is identical in the two introns and cannot be assigned to either of them.