Congenital Hypothyroidism (CHG) - Tenterfield Terrier

Congenital hypothyroidism with goiter (CHG) is an endocrine disorder characterized by enlarged thyroid glands (goiter). The underlying cause of this disorder is an inability of the thyroid glands to produce sufficient hormone levels to inhibit the release of thyrotropin in the pituitary gland. This in turn causes structural abnormalities in the thyroid glands. The disorder can be inherited or acquired by dietary iodine deficiency or excess, or by exposure to goitrogenic compounds. Genetically inherited CHG occurs in several dog breeds, including Tenterfield Terriers. The affected dogs show growth failure with short legs at around 3 weeks of age. Other symptoms include later opening of eyes, severe mental retardation, opaque corneas, lethargy, abnormal coat texture, difficulty in nursing and enlarged thyroid glands causing neck swelling and obstructing the airways. CHG is a lethal disorder, but treatment is possible by early implementation of thyroid hormone replacement therapy. Genetic testing could be used to diagnose CGH early or to prevent future cases by carrier detection.

Inheritance: autosomal recessive

Mutation:  TPO gene

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