The Burmese breed of cat originated in the 1930’s. A phenotypic change occurred in the 1970’s when the “Eastern”, “new look”, “contemporary”, or “more extreme” style became prominent. These cats differed from the “traditional” or “less extreme” cats with a higher frontal prominence, more rounded head, more prominent eyes and a more demarcated nose break. After this phenotype became more widely distributed, some breeding lines produced kittens with a severe congenital craniofacial defect. This disease follows an autosomal recessive mode of inheritance and is characterized by a duplication of the upper maxillary, whisker pads and incomplete formation of the cranium. This condition is fatal although kittens must occasionally be euthanized post parturition. Research has established linkage to three markers with the disease phenotype. One of the developmental gene clusters, HOXC, lies on the edge of the linked region. This cluster of genes has been studied extensively in mouse, frog and avian models, which have elucidated genes in pathways of development. Therefore, HOXC may contain the causative mutation for the defect, and is a strong candidate. This research will focus on the sequencing of this cluster of genes from affected and unaffected cats to identify a mutation causing this inherited defect.