The effect of the deletion on the ARHGEF10 transcript was investigated with cDNA prepared from the nervous tissue of an early-onset Leonberger PN case homozygous for the CFA16 haplotype (D/D), a CFA16 haplotype heterozygote (D/N) Leonberger with no polyneuropathy, and one control dog (N/N). Here, ARHGEF10 is linked to poikiloderma with neutropenia.