Pherograms of the mutations are also shown, with mutations indicated by black arrows. The mutation causing diabetes in kindred D, LB15YB16delinsH, was determined by subcloning of the PCR product and DNA sequencing, confirmed in 10 clones. Mutations LB11P and YA19X, which respectively introduce HpaII and SpeI restriction sites, were both confirmed (white arrows) by RFLP-PCR. n, normal allele; m, mutant allele; p, proband. Patients carrying mutations are denoted by filled symbols.