Research Communications of the 24th ECVIM-CA Congress

The TPO enzyme activity was extremely low in hypothyroid cats when compared to that of normal cats. Genomic DNA and cDNA from affected, carrier, and normal cats were extracted and sequenced based upon primers developed from the feline genome database. A homozygous missense point mutation (c.1333G>A) in TPO, which results in an amino acid change (p.Ala445Thr), was discovered in affected cats and the mutant allele segregated within the family with goiterous CH. This is the first report of a TPO deficiency in cats. Other unrelated domestic shorthair cats with goiterous CH did not have this same TPO mutation. The prevalence of this TPO mutation in the domestic cat population seems low, but CH is likely underreported in cats.