Other Names: Ivermectin Sensitivity
In English: Multidrug Resistance 1, ABCB1-related
Affected Gene: ABCB1
Transmission: Incomplete autosomal dominant
Mutation: 4 bp deletion CanFam3.1 14 g.13726596_13726599del c.228_231del p.(D77Afs*16)
OMIA Link: 001402-9615

Breeds Recommended for Testing: German Shepherd, Miniature American Shepherd, Australian Shepherd, Miniature Australian Shepherd, Swiss White Shepherd, Shetland Sheepdog, McNab Shepherd, Picard Shepherd, Border Collie, Australian Cattle Dog, Chinook, Collie, Smooth Coat Collie, Rough Coat Collie, Koolie, Silken Windhound, Longhaired Whippet, Old English Sheepdog/English Shepherd/Bobtail, Ryukyu Inu, Shiloh Shepherd, Waller

Symptoms:
Multidrug resistance 1 is caused by a deficiency of the P-glycoprotein drug transporter in the blood-brain barrier, leading to neurotoxicity after the administration of certain drugs.

References:
Mealey, K.L., Meurs, K.M. Breed distribution of the ABCB1-1Delta (multidrug sensitivity) polymorphism among dogs undergoing ABCB1 genotyping. J Am Vet Med Assoc 233:921-4, 2008. PubMed: 18795852
DOI: 10.2460/javma.233.6.921
Mealey, K.L., Munyard, K.A., Bentjen, S.A. Frequency of the mutant MDR1 allele associated with multidrug sensitivity in a sample of herding breed dogs living in Australia. Vet Parasitol 131:193-6, 2005. PubMed: 15975717
DOI: 10.1016/j.vetpar.2005.05.004
Mealey, K.L., Bentjen, S.A., Gay, J.M., Cantor, G.H. Ivermectin sensitivity in collies is associated with a deletion mutation of the mdr1 gene. Pharmacogenetics 11:727-33, 2001. PubMed: 11692082