Two allelic, autosomal recessive mutations in the Sharpin gene occurred spontaneously in two inbred strains of mice, C57B/KaLawRij-Sharpincpdm/Sharpincpdm and CBy.Ocb3/Dem-Sharpincpdm-Dem/Sharpincpdm-Dem, resulting in premature termination of mRNA synthesis and absence of a functional protein product [2].