Amelogenesis imperfecta

 

Gene: ENAM

Transmission: Autosomal, recessive

For an autosomal recessive genetic disease an animal must have two copies of the mutation in question to be at risk of developing the disease.  Both parents of an affected animal must be carriers of at least one copy of the mutation.  Animals that have only one copy of the mutation are not at risk of developing the disease but are carrier animals that can pass the mutation on to future generations.

Mutations: 

Italian Greyhound mutation: Deletion, ENAM gene; c.1991_1995 del.5 bp (TTTCC), p.(F665R fs STOP 3), exon10

Parson Russel Terrier mutation: Substitution, ENAM gene; c.716 C>T, p.(P239L)

Medical systems: skeletal, dental

Breeds: American Staffordshire Terrier/Amstaff, Bedlington Terrier, Border Collie, Boston Terrier, Chihuahua, Danish Swedish Farmdog, English Cocker Spaniel, Italian Greyhound, Parson Russell Terrier, Pomeranian, Pug, Russell Terrier

Age of onset of symptoms: At birth, but more visible when permanent teeth appear

Familial Enamel Hypoplasia is a genetic disease of tooth development involving enamel hypoplasia and thinning.  Enamel is the hard, smooth surface that forms the crown of teeth and which provides protection to the underlying dentine.  The teeth of affected animals are rougher, thinner, smaller and more pointed than normal and have a brown discoloration.  In addition, the gaps between teeth are more pronounced than normal.  Although the enamel is damaged, the rest of the basic structure of the teeth remains intact throughout the dog’s life.  Affected dogs can experience dental fractures and cavities more frequently than non-affected dogs, but in general they will have a normal life expectancy and quality.  No other organ is affected.

 

References:

OMIA link: [1805-9615]

Donner J, Freyer J, Davison S, et al. (2023) Genetic prevalence and clinical relevance of canine Mendelian disease variants in over one million dogs.  PLoS Genet. 19(2):e1010651. [pubmed/36848397]

Hytönen MK, Arumilli M, Sarkiala E, et al. (2019) Canine models of human amelogenesis imperfecta: identification of novel recessive ENAM and ACP4 variants. Hum Genet 138:525-533. [pubmed/30877375]

Gandolfi G, Liu H, Griffioen L, Pederson NC. (2013) Simple recessive mutation in ENAM is associated with amelogenesis imperfecta in Italian Greyhounds.  Animal Genetics 44 :569-578. [pubmed/23638899]