Coral Springs Animal Hospital's Pawfessional Spring 2017 | Page 10

present. A repeat thyroid profile was
submitted, with the blood having
been taken 4-6 hours after her
morning dose of medication. Her T4
was 2.4 ng/dL, FT4 ng/dL was 0.8
and her FT4 pmol/L was 10.3
(reference range for T4 and FT4 1-4
ng/dL). Willow was looking and
acting like a normal cat. We are
keeping her at a dose of 0.1mg
Levothyroxine daily long term.
Congenital primary hypothyroidism
causing disproportionate dwarfism is
recognized more frequently than
adult-onset hypothyroidism in the
cat. Reported causes of congenital
hypothyroidism include a defect in
thyroid hormone biosynthesis, most
notably an iodine organification
defect and thyroid dysgenesis. An
inherited
defect
in
iodine
organification was documented in a
family of Abyssinian cats with
congenital
hypothyroidism.
Inbreeding of affected cats resulted
in hypothyroidism in all offspring,
whereas breeding affected cats to
unrelated
cats
resulted
in
phenotypcally normal kittens. These
results suggest an autosomal
recessive mode of inheritance for
the disease in this family of cats.