Genetic basis of Amelogenesis Imperfecta in Italian Greyhounds - is caused by a simple autosomal recessive mutation within the ENAM gene, which encodes enamelin, a protein critical for enamel development and mineralization. Specifically, the mutation is a 5-base pair deletion in exon 10 of ENAM (c.1991_1995delTTTCC), causing a frameshift and premature termination of the protein. The trait is inherited in an autosomal recessive manner: affected dogs are homozygous for the mutation, while carriers are heterozygous and asymptomatic but can pass the mutation to offspring. Genetic testing to detect carriers and affected dogs is available and essential for breeding management.
Pathophysiology - The ENAM mutation impairs enamel protein function, leading to defective formation of dental enamel. Affected dogs show hypoplasia and hypomineralization of enamel, resulting in rough, thin, and mottled enamel with brown or gray discoloration. The enamel defects affect both deciduous (baby) and permanent teeth. Affected teeth tend to be smaller, pointed, and have increased spacing (gaps) due to premature enamel wear. Despite the enamel defects, basic tooth structure is typically maintained, and the risk of fractures or cavities is lower than in human AI.
Complications - Teeth abnormality can lead to dental sensitivity or discomfort and cosmetic issues. Teeth may have rough, irregular surfaces that wear excessively over time, causing larger than normal gaps. There is generally no association between AI and other systemic diseases, autoimmunity, or increased periodontal disease. Dental care may be required to manage enamel wear, but severe dental health problems are uncommon.
Why This Matters to Breeders and Vets - For breeders, it is crucial to identify carriers through genetic testing to avoid carrier × carrier breedings that produce affected puppies. AI is relatively prevalent in Italian Greyhounds in the USA and Canada, with about 14% affected and up to 30% carriers in some populations. Veterinarians should recognize the clinical signs for diagnosis and differentiate AI from other dental diseases, advising owners on dental care. Genetic testing allows informed breeding decisions to reduce the disease prevalence over time.
Summary - Amelogenesis Imperfecta (Italian Greyhound Type) is an autosomal recessive enamel defect disorder caused by a frameshift mutation in the ENAM gene. It results in generalized enamel hypoplasia, with smaller, pointed, rough teeth and discoloration affecting both baby and adult teeth. Although no systemic health problems are associated, affected dogs have abnormal tooth enamel that may require dental management. Genetic testing for the ENAM mutation is key for breeders to avoid producing affected litters and to manage the condition responsibly in breeding programs.