Detection of the delG mutation by PCR-RFLP.

(A) A mutagenic primer (E9Gdel) with one base mismatch (G in italics) was designed to create an EcoRI site only in the PCR product with a normal sequence. (B) Amplified products from patients (patient 4, P4; patient 5, P5), and a normal control (C) were treated withEcoRI and then electrophoresed in a 2% agarose gel. The product of 260 bp amplified from the normal allele is cleaved into 2 fragments of 236 bp and undetectable 24 bp. An uncleaved PCR product (UC) amplified from patient 4 was also applied as a negative control.