Dwarfism

Definition

Dwarfism is defined as underdevelopment of the body, or the state of being short in stature. Most dwarf dogs suffer from a condition called “osteochondrodysplasia,” which simply refers to any abnormality in the growth and development of bone, (“osteo-“), cartilage (“chondro-“), or both. Dwarfism almost always occurs in young, growing puppies and typically affects the long bones of all four legs. These are called the radius, ulna and humerus (in the front legs), and the tibia, fibula and femur (in the hind legs).

Certain breeds have been selectively bred to be genetic dwarfs. Intentional canine dwarfs have severe skeletal defects in their legs, and sometimes in their skulls and spines as well. Such abnormal conformational traits are considered to be normal and indeed desirable in those breeds. Dogs breeds that have been developed over the years to have dwarfism as a breed characteristic include the Bulldog, Japanese Spaniel, Pug, Shih-Tzu, Pekingese, Boston Terrier, Dachshund, Beagle, Welsh Corgi, Scottish Terrier, Skye Terrier, Basset Hound and Dandie Dinmont Terrier.

Unfortunately, dogs in breeds that have not been selectively bred for short stature can also be born as dwarfs. This is definitely not considered to be normal. This type of dwarfism usually is the result of a genetic defect that causes the puppies to develop abnormally inside of their mother’s uterus and also after they are born. These puppies typically have what is called “disproportionate dwarfism,” with abnormally short legs relative to their bodies, which appear overly-long. Their skulls usually are not affected by the growth disorder. Breeds that have not been specifically bred for dwarfism but that reportedly are at risk of producing dwarfs include the Labrador Retriever, Norwegian Elkhound, Cocker Spaniel, Scottish Terrier, Scottish Deerhound, Alaskan Malamute, Great Pyrenees, Bull Terrier, Irish Setter, Miniature Poodle, Beagle, Samoyed, English Pointer and Great Dane.

A different type of abnormal growth is referred to as “pituitary dwarfism.” Pituitary dwarfism is thought to be a hereditary defect in some German Shepherd Dogs, Carnelian Bear Dogs, Labrador Retrievers, Weimaraners, Spitz and Miniature Pinschers.