Mutation Analysis
(A) Bioinformatics analysis indicated the existence of two SMARCAD1 isoforms differing both in lengths and sites of transcription start site. The short SMARCAD1 isoform contains a unique nontranslated exon (red arrow).
(B) Sequence analysis revealed a heterozygous transversion, c.378+1G>T, in the short SMARCAD1 isoform (red arrow, left panel). The wild-type sequence is given for comparison (right panel).
(C) PCR-RFLP analysis confirmed segregation of the mutation in the family. Mutation c.378+1G>T creates a recognition site for MseI endonuclease; thus, healthy individuals display fragments of 163 bp and 46 bp, whereas affected heterozygous patients show in addition fragments of 73 bp and 90 bp.