Identification of a novel frameshift mutation in the DMD gene as the cause of muscular dystrophy in a Norfolk terrier dog.

BACKGROUND: A Norfolk terrier was referred to the Animal Health Trust neurology department with suspected dystrophin-deficient muscular dystrophy (DD-MD), which was confirmed by clinical workup and immunohistochemistry.

FINDINGS: Exon resequencing of the canine Duchenne Muscular Dystrophy (DMD) gene was undertaken to screen for potential disease causing mutations. The sequence data generated from all coding DMD exons revealed a 1 bp deletion in exon 22, causing a frameshift and premature termination of the coding sequence. Gene expression analysis indicated reduced levels of dystrophin transcript in the DD-MD case and western blot confirmed the absence of full length protein.

CONCLUSIONS: The finding represents a novel mutation causing DD-MD in the dog.