Hereditary Vitamin D-Resistant Rickets

Symptoms include lameness and skeletal abnormalities, most noticeably an outward bowing of the forelimbs. Due to insufficient amounts of calcium deposition in the bone matrix, dogs are also prone to spontaneous fractures.

Signs are first recognized in puppies.

Genetic testing, clinical signs, radiographs, and laboratory tests are all used to diagnose this condition.

If left untreated, dogs deteriorate rapidly. Because nutritional rickets is much more common than HVDRR, affected dogs are often incorrectly treated for nutritional rickets to no avail and are often euthanized due to poor response to therapy. Catching HVDRR early can inform appropriate treatment. However, any skeletal abnormalities that develop prior to treatment are permanent.

Talk to your vet about your dog’s hereditary vitamin D–resistant rickets result so you can plan appropriate monitoring and care.

Work with your vet to ensure your dog receives proper nutrition and supplements to support healthy bone development.

Watch for signs such as limb weakness, difficulty walking, or bone pain, and contact your vet promptly if you notice any changes.

This mutation was first described in a Pomeranian.

Penetrance: This mutation has an autosomal recessive inheritance, meaning that dogs must have two copies of the mutation in order to show clinical signs.

Gene

VDR (Exon 4)

Inheritance type

recessive

Clinical category

Skeletal

Citations

1. LeVine et al 2009

• Pomeranian