Extended Data Fig. 2: SPTLC1 variant associated with amyotrophic lateral sclerosis and their effects on splicing.

a, Gel electrophoresis of PCR amplification of cDNA obtained from patient fibroblast cultures or whole blood. Fibroblasts were not available for c.58G>T patient. PCR primers were in exon 1 and 6 of SPTLC1 (NM_006415.4). SPTLC1 c.58G>T variant resulted in two bands with an apparent difference of ~100 bp. All other variants and controls resulted in a single band. b, Sequencing of the gel purified PCR product showed that the c.58G>T variant resulted in complete skipping of exon 2 (lower band). Neither the full-length product (upper band) nor the internally deleted transcript (lower band) contained the c.58G>T variant. However, it is possible that the missense variant exists in very small amounts and escaped amplification by PCR and sequencing. All other variants were confirmed and do not affect splicing.