Dermoid Sinus (Ridge Gene) - SINGLE ASSAY TEST

US$ 75.00 RRP

US$ 50.00 (USER PRICE)


This is a developmental condition where during development of the embryo the tissue layers that will go on to form the spinal cord and the skin fail to separate properly.

In the puppy this results in a small tunnel remaining that leads from the spinal column to the skin surface. It is most commonly seen in the Rhodesian ridgeback, and is occasionally seen in several other breeds.

In the Rhodesian ridgeback this disorder is inherited, and is associated with the gene that produces the ridge on the back. The skin tunnel (or sinus) can be felt in the puppy as a thin thread of tissue running down under the skin when the skin is gently lifted, and is usually found at either end of the ridge. In most countries,the majority of these puppies are euthanased, however this is less common in the USA.

Treatment involves removing the sinus, and is a complex surgery that involves working into the spinal canal. Left untreated, skin cells can enter this tunnel and can cause infections and abscesses, and these infections can track along the sinus and into the spinal canal.

Recent advances and publications reported in the literature that this trait is inherited as a dominant trait with incomplete penetrance. This has implications for possible carriers and breeding recommendations.

Test Overview:

Please note that this test requires an additional set of swabs to be submitted.


Nervous system / Neurologic - Associated with the brain, spinal cord and nerves


gene FGF4, FGF3, FGF19, ORAOV1, CCND1

Variant Detected:

Duplication 133 kbp chr18:51398518-51531941


Moderate-Severe. This is a disease with significant welfare impact on the affected animal, in terms of clinical signs and generally reduced life expectancy.

Mode of Inheritance:

Autosomal Dominant with Incomplete Penetrance

Research Citation(s):

Nat Genet. 2007 Nov;39(11):1318-20. Epub 2007 Sep 30. Duplication of FGF3, FGF4, FGF19 and ORAOV1 causes hair ridge and predisposition to dermoid sinus in Ridgeback dogs. Salmon Hillbertz NH1, Isaksson M, Karlsson EK, Hellmén E, Pielberg GR, Savolainen P, Wade CM, von Euler H, Gustafson U, Hedhammar A, Nilsson M, Lindblad-Toh K, Andersson L, Andersson G.

Associated Breed(s):

Rhodesian Ridgeback ,