Pseudoachondroplasia is a form of achondroplasia characterized by abnormal development of skeletal bones that becomes evident at about 2-3 weeks of age. The disease is also called spondyloepiphyseal dysplasia, epiphyseal dysplasia and chondrodystrophia fetalis. Pseudoachondroplasia is different from achondroplasia in that it is marked by short limbs and a normal head, while achondroplasia is characterised by short legs and enlarged head. The prefix "pseudo" before achondroplasia means that the disorder resembles achondroplasia but is actually different in that the signs are the same as for achondroplasia, except the head is normal size. Mild inferior prognathism may be present.5 The disorder is caused by mutations in the cartilage oligomeric matrix protein gene. Both sexes may be affected. An autosomal recessive form of this disorder has been reported in the Miniature Poodle and Scottish Deerhound.
The pseudoachondroplastic dogs are distinguished by a bone growth rate that is 65 percent of that in normal animals.4 Affected puppies show retarded growth and inability to walk or stand. The long bones are short, thick and bent, and the joints are enlarged and stiff. The flattened rib cage makes breathing difficult. General health is otherwise good except for arthritis. The diagnosis of pseudoachondroplasia can be made on the basis of clinical findings and radiographic examination.
- Roy Robinson. Genetics for Dog Breeders.
- GJ Breur, CE Farnum, GA Padgett and NJ Wilsman. Cellular basis of decreased rate of longitudinal growth of bone in pseudoachondroplastic dogs.
- Peter F. Jezyk. Constitutional Disorders Of the Skeleton In Dogs and Cats.
- C. G. Scanes. Biology of growth of domestic animals
- K. V.F. Jubb, Peter C. Kennedy. Pathology of Domestic Animals