These authors contributed equally to this work.
The inheritance of extra-hepatic portosystemic shunts and elevated bile acid concentrations in Maltese dogs
Article first published online: 2 DEC 2013
© 2013 British Small Animal Veterinary Association
Journal of Small Animal Practice
Volume 55, Issue 1, pages 14–21, January 2014
How to Cite
O'Leary, C. A., Parslow, A., Malik, R., Hunt, G. B., Hurford, R. I., Tisdall, P. L. C. and Duffy, D. L. (2014), The inheritance of extra-hepatic portosystemic shunts and elevated bile acid concentrations in Maltese dogs. Journal of Small Animal Practice, 55: 14–21. doi: 10.1111/jsap.12156
G. B. Hunt's current address is Department of Surgery, University of California, Davis, CA, USA
P. L. C. Tisdall's current address is Adelaide Veterinary Specialist & Referral Centre, 102 Magill Road, Norwood, SA 5067, Australia
- Issue published online: 6 JAN 2014
- Article first published online: 2 DEC 2013
- Accepted: 22 September 2013
To determine the heritability of extra-hepatic portosystemic shunts and elevated post-prandial serum bile acid concentrations in Maltese dogs.
MATERIALS AND METHODS
Maltese dogs were recruited and investigated by a variable combination of procedures including dynamic bile acid testing, rectal ammonia tolerance testing, ultrasonography, portal venography, surgical inspection or necropsy. In addition, nine test matings were carried out between affected and affected dogs, and affected and unaffected dogs.
In 135 variably related Maltese, shunt status could be confirmed in 113, including 19 with an extra-hepatic portosystemic shunt (17 confirmed at surgery, 2 at necropsy). Rectal ammonia tolerance testing results and post-prandial serum bile acid concentrations were retrievable for 50 and 88 dogs, respectively. Pedigree information was available for these 135 and an additional 164 related dogs. Two consecutive test matings were carried out between two affected animals (whose shunts had been attenuated), with 2 of 8 (25%) of offspring having an extra-hepatic portosystemic shunt. Six test matings were carried out between an affected and an unaffected animal, with 2 of 22 (9%) offspring affected. Heritability of extra-hepatic portosystemic shunt was 0·61 calculated using variance components analysis [95% confidence interval (CI) 0·14 to 1·0, P=0·001]. The best fitting model from segregation analysis was a common, partially penetrant, recessive model (allele frequency 0·34, penetrance 0·99, CI 0·09 to 1·0). The heritability of elevated post-prandial serum bile acid (and thus likely portal vein hypoplasia) was 0·81 (CI 0·43 to 1·0, P=0·2) after logarithmic transformation of post-prandial serum bile acid concentrations.
There is strong support for extra-hepatic portosystemic shunts and elevated post-prandial serum bile acid concentrations both being inherited conditions in Maltese.