Proportionate Dwarfism


Embark’s data suggests that this variant in the GH1 gene may contribute to a smaller body size. The original publication predicts this is due to a growth hormone (GH) deficiency. However, adult body size is influenced by several different genetic variants. Other changes noted by the publication, including retained baby teeth, persistent puppy-like coats, and low blood sugar have been occasionally reported by owners of dogs with two copies of this variant. These changes may or may not be associated with this variant.

  • Signs and symptoms

    A smaller-than-expected adult weight is possible. Rarely, dogs with this variant may have low blood sugar, retained baby teeth, and a persistent puppy-like coat. Low blood sugar, if it occurs, causes lethargy and weakness. However, these issues are present across multiple toy breeds and may not be caused by this variant.

    Dogs with this variant may never show clinical signs. Smaller stature may be noticeable if the puppy grows at a different rate than littermates without this variant. Low blood sugar is a potential issue common to most toy breeds but could persist beyond four months of age. Retained puppy teeth and puppy-like coats can only be noted at more than six months of age.

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  • Diagnosis

    Clinical history, genetic testing, and laboratory testing can be used to diagnose this form of Proportionate Dwarfism. Further research is needed to determine the full effects of this variant.

  • Treatment

    Our internal data suggests that most dogs with two copies of this variant will not require additional care than other toy breed puppies. If a complication occurs, your veterinarian may recommend various treatments, including correcting blood sugar or extracting retained baby teeth.

  • What to do if your dog is at risk


    • Monitor for signs of hypoglycemia, including not eating, lethargy, and inability to stand. Call your veterinarian immediately for advice if you notice these signs.

  • Genetic Information

    This variant was first described in the Chihuahua.

    This variant is inherited in an autosomal recessive manner, meaning that a dog requires two copies of the variant to show signs of proportionate dwarfism.

    Gene names:

    GH1 Exon 5 ‐ chr

    Inheritance type:



    Iio et al 2020

  • Breeds affected

    This health condition affects the following breeds

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