Dwarfism (growth-hormone deficiency) - Chihuahua

General description

In the breed Chihuahua, a genetic variant of the GH1 (growth hormone) gene has been found to be associated with dwarfism and hypoglycemia. A six-month-old Chihuahua dog, homozygous for the described variant, showed proportionate dwarfism, retained puppy hair coat, retained deciduous teeth, open fontanelles and collapsed because of hypoglycemia once every 3 days. Blood tests revealed hypoglycemia, thrombocytosis, hypoproteinemia and elevated alkaline phosphatase activity. Organic abnormalities in the pituitary gland have not been found.