Genomic DNA was extracted from peripheral white blood cells of all subjects. Three SNPs in the LOXL1 gene—rs2165241, rs1048661, and rs3825942—were amplified by polymerase chain reaction (PCR; model 9700 thermocycler; Applied Biosystems [ABI], Foster City, CA). PCR reactions were performed in 50-μL volumes containing 10 mM Tris HCl (pH 8.9), 50 mM KCl, 1.5 mM MgCl2, 25 picomoles of each primer, 200 μM each dNTP, 50 to 100 ng of patient genomic DNA, and 0.7 units of Taq thermostable DNA polymerase (Promega, Madison, WI). Cycling parameters were 3 minutes at 95°C, followed by 35 cycles of 30 seconds at 95°C, 30 seconds at the melting temperature (Tm) of the primers (52°C–62°C), and 30 seconds to 1 minute at 72°C with a final 5-minute extension at 72°C. The products were purified with PCR clean-up columns (GFX; GE Healthcare, Piscataway, NJ). Sequence variations were identified by automated bidirectional sequencing (BigDye terminator ver. 3.1 chemistries; ABI). An automated DNA sequencer (Prism 3100; ABI) was used. Primers for sequence reactions were the same as those for the PCR reaction.