Congenital Hypothyroidism (CHG) - Toy Fox Terrier

Congenital hypothyroidism with goiter (CHG) in Toy Fox Terriers and Rat Terriers is an endocrine disorder characterized by inadequate T4 levels early in life concurrent with signs of hypothyroidism.  Without early diagnosis and treatment (oral thyroid hormone replacement therapy), typical clinical signs include growth retardation (dwarfism), delayed onset of developmental milestones such as eye opening and tooth eruption, abnormal hair and skin texture, epiphyseal dysplasia, mental retardation, unresponsiveness and lethargy. The disorder is lethal unless diagnosed and treated early. Congenital hypothyroidism in this breed is often presented with goiter - a swelling in the neck resulting from an enlarged thyroid gland.

Inheritance: autosomal recessive

Mutation: TPO gene

Genetic test: The method used for testing is extremely accurate and allows complete differentiation between affected animals, carriers and healthy dogs. Testing can be done at any age.