Mutation detection in the genomic DNA from Patient 0300. (A) SSCP analysis of exon 1 and flanking sequences from a control (lane labeled c) and patients with XLA. Patients 0030 and 0025 are shown in lanes 1 and 10, respectively. (B) DNA sequence of the 5′ part of intron 1 from a control and from Patient 0030. The 3′ end of exon 1 is indicated in the control sequence. The T to G transversion in the patient is denoted by an asterisk.