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White spotting phenotypes in horses may be caused by developmental alterations impairing melanoblast differentiation, survival, migration and/or proliferation. Candidate genes for white-spotting phenotypes in horses include EDNRB, KIT, MITF, PAX3 and TRPM1. We investigated a German Riding Pony with a sabino-like phenotype involving extensive white spots on the body together with large white markings on the head and almost completely white legs. We obtained whole genome sequence data from this horse. The analysis revealed a heterozygous 1273-bp deletion spanning parts of intron 2 and exon 3 of the equine KIT gene (Chr3: 79 579 925-79 581 197). We confirmed the breakpoints of the deletion by PCR and Sanger sequencing. Knowledge of the functional impact of similar KIT variants in horses and other species suggests that this deletion represents a plausible candidate causative variant for the white-spotting phenotype. We propose the designation W28 for the mutant allele.

The small punch test was developed to investigate the mechanical behavior of polyethylene using miniature specimens (< 14 mg) measuring 0.5 mm in thickness and 6.4 mm in diameter. The objective of this study was to demonstrate the feasibility and reproducibility of the small punch test when applied to clinically relevant polyethylenes. Mechanical behavior was characterized during 66 tests performed on GUR4150HP and GUR4120 specimens following alternate sterilization methods and 4 weeks of accelerated aging at 80 degrees C. The small punch test was found to be highly reproducible with regard to characterizing the ductility, ultimate strength, and fracture resistance of sterilized and aged polyethylene. In the future, the small punch test can be used to directly measure mechanical properties near the articulating surface of retrieved components.