By examining three comparative positional candidate genes from their mapping results (see Mapping section), Krebs et al. (2007) reported strong evidence that this disorder in cattle is due to a mutation in "FVT1, encoding 3-ketodihydrosphingosine reductase, which catalyzes a crucial step in the glycosphingolipid metabolism". Specifically, the mutation is "a G-to-A missense mutation that changes Ala-175 to Thr". Interestingly, the FVT1 gene, officially known as KDSR, is not included in the list of genes in which mutations result in SMA in humans. In their table of reduced-fertility haplotypes, Cole et al. (2014) list this KDSR mutation as being the causal mutation for haplotype BHM, which is located at 62,118,139– 62,156,760bp on chromosome BTA24.
