Dysplasia is an abnormality of the histogenesis that manifests through one or more morphological defects resulting from the disorganization of the cells and other components of a tissue, which consequently has abnormal architecture . If a dysplasia affects the cartilaginous tissue it is known as chondrodysplasia and has negative reflexes on the development of the whole skeleton, commonly causing disproportion between the skeletal segments [2,3]. Dysplasia in general can be linked to environmental factors or be caused by genetic factors, with the latter being the most significant from a clinical-genetic viewpoint [2-5].
The term bovine prenatal lethal chondrodysplasia (BPLC) comprises a heterogeneous group of genetic chondrodysplasias characterized by extremely severe micromelic dwarfism that causes intrauterine death, normally between the 6th and 8th month of gestation. Because of the affected individuals have a typical phenotype that bears some resemblance to a bulldog, cattle farmers know them as â€œbulldog calvesâ€, and this expression has also been used frequently in veterinary medicine [6-8].
Since the eighteenth century, references have been made to the â€œmonstrous bulldog calfâ€, and since that time, a resemblance has been noted between several of its characteristic traits and those of human achondroplasia [9,11]. However, to the best of our knowledge, the first scientific report on BPLC was only published in 1904, describing it in the Dexter breed under the denomination of â€œcretinism in calvesâ€ and already raising the hypothesis that it was a hereditary anomaly resulting from Mendelian inheritance . The characteristic phenotype attracted the attention of comparative medicine and, in 1923, the doctor and researcher F. A. E. Crew, professor of animal genetics at the University of Edinburgh, published a study suggesting that in the Dexter breed the bulldog calf was a severe and non-viable form of achondroplasia in calves. That being the case, it would serve as a model spontaneous animal for studies concerning human achondroplasia . Several studies have shown that the inheritance of chondrodysplasia in the Dexter breed follows an incomplete dominance mechanism (semidominance), which is more severe in homozygotes, similar to what happens in cases of human achondroplasia [6,8,11]. However, nowadays it is known that despite their similarities, these two conditions are caused by mutations in different genes [8,12,13].
In addition to the well-documented occurrence in the Dexter breed, BPLC has also been reported in other breeds. In these cases, it has sometimes been referred to as Dexter bulldog type chondrodysplasia or Dexter type dwarfism . However, although the phenotype is essentially the same, the genetic aspects still require clarification [7,15]. There are reports of cases in the Holstein and Jersey breeds and in a Holstein-Jersey crossbreed [7,14,16,17].
In this review, we set out to provide an overview of the current state of knowledge of the genetics and anatomical pathology of BPLC, suggesting etiological possibilities based on human clinical genetics, and to record a spontaneous case in the Nellore breed.
Citation: Moura E, Prado AMRB, Pimpao CT, Murakami CT, Ribeiro DR (2014) Genetic and Pathoanatomical Features of the Bovine Prenatal Lethal Chondrodysplasia . Hereditary Genet 3:132. doi: 10.4172/2161-1041.1000132