Pituitary dwarfism is a rare inherited failure of the anterior pituitary to develop, best known in German Shepherd Dogs. Affected puppies stop keeping pace with their littermates at a few weeks of age, keep a soft puppy coat, and develop secondary hypothyroidism, so the condition is really a combined pituitary hormone deficiency rather than a pure growth hormone (GH) problem. The opposite disorder, GH excess (acromegaly), is also covered here because in dogs it is usually driven by the same mechanism that is exploited to treat dwarfs: progesterone-induced GH production by the mammary gland.
Key facts
Growth hormone disorders (pituitary dwarfism) at a glance- Species / system: Dog; adenohypophysis (endocrine).
- Cause: Autosomal recessive 7 bp deletion in intron 5 of LHX3, a transcription factor needed for pituitary development. Craniopharyngioma is the second most common cause of juvenile GH deficiency.
- Breeds: German Shepherd Dog above all; also Saarloos and Czechoslovakian wolfdogs, White Swiss Shepherd and Tibetan Terrier (same LHX3 variant). Karelian Bear Dogs have a different gene (POU1F1).
- Classic presentation: A 2–4-month-old German Shepherd puppy that is proportionately small, fox-like, with a woolly puppy coat, no guard hairs and later truncal alopecia.
- Hormones lost: GH, TSH, prolactin and gonadotropins. ACTH is usually spared.
- Key treatment: Levothyroxine for life, with porcine GH or a progestin to improve size and coat.
- Not zoonotic or reportable.
What's inside
13 sections in the full guide- Key facts
- How the NAVLE tests this
- Cause and pathophysiology
- Clinical signs
- Diagnosis
- Differential diagnoses
- Treatment and management
- Growth hormone excess: acromegaly in dogs
- Prevention, control and breeding
- Prognosis
- Quick review
- Test yourself
- References
Read the full study guide
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