(A) PCR-SSCP analysis. (B) Restriction endonuclease analysis of exons 3 and 4 including intron/exon junctions. Lane 1, chorionic villus sample (IV.3); lane 2, normal control; lane 3, affected child (IV.2); lane 4, father (III.5); lane 5, mother (III.6). An arrow indicates extra band with altered migration, when compared with normal control bands.