JLPP in Rottweilers: The RAB3GAP1 DNA Test

What JLPP is

JLPP stands for Juvenile Laryngeal Paralysis and Polyneuropathy. In Rottweilers it is also documented under the names Neuronal Vacuolation and Spinocerebellar Degeneration (NVSD) and Polyneuropathy with Ocular Abnormalities and Neuronal Vacuolation (POANV). It is a hereditary neurological disease, and it is fatal. There is no cure and no effective treatment.

The disease is caused by a single-nucleotide deletion in the RAB3GAP1 gene, written as c.743delC. It is autosomal recessive. A dog must inherit two copies of the mutation — one from each parent — to be affected. A dog carrying a single copy is an unaffected carrier and will never develop the disease itself.

Symptoms and onset

Onset is juvenile, typically around three months of age (roughly 10 to 12 weeks, with a reported range of two to four months). This timing is the cruel part: because signs do not appear until this age, affected puppies are often already placed in their new homes before anything looks wrong.

Clinical signs include:

• Laryngeal paralysis — difficulty breathing when excited or exercised, and a noticeable change in the bark.
• Polyneuropathy — weakness and loss of coordination that starts in the hind limbs and progresses to the front limbs.
• Difficulty swallowing — which can lead to choking or aspiration pneumonia.

The literature also describes axonal peripheral neuropathy and, as part of the broader POANV spectrum, ocular abnormalities such as microphthalmia and congenital cataracts. The disease is progressive: even with supportive nursing care, affected dogs do not live more than a few months after signs begin. Most are euthanized or die from respiratory distress and declining quality of life, generally before one year of age.

The DNA test ends the guesswork

The mutation was identified by Mhlanga-Mutangadura and colleagues in a 2016 study published in the Journal of Veterinary Internal Medicine. That work enabled a direct DNA test, now offered through laboratories including the UC Davis Veterinary Genetics Laboratory. The test returns three genotypes:

• Clear / Normal (N/N) — no mutant copies; cannot develop the disease and cannot pass it on.
• Carrier (N/JLPP) — one mutant copy; clinically normal, but transmits the variant to about 50% of offspring.
• Affected / At-Risk (JLPP/JLPP) — two mutant copies.

How responsible breeding eliminates affected puppies

Because the disease is recessive, a Clear (N/N) parent passes only a normal allele to every puppy. That is the whole strategy. Breeding a carrier to a clear dog guarantees no affected (homozygous) puppies — though roughly half of that litter may themselves be carriers, which is harmless and keeps a valuable dog in the gene pool. The rule to never break is the reverse: never breed carrier to carrier, the only pairing that can produce an affected puppy.

This is why testing every breeding dog matters. Reported carrier frequency in the breed is meaningful — on the order of 15-19% in the U.S. (OFA statistics) and high-teens to roughly 20% in Germany (ADRK and Laboklin data, as reported) — so carriers are common enough that no serious program can assume a dog is clear without proof. The American Rottweiler Club's mandatory practices require that at least one parent of any member breeding be JLPP-clear — by DNA test, or clear-by-parentage — with results recorded with the OFA.

At DN Rottweilers, every breeding dog is JLPP-tested and we breed only carrier-to-clear or clear-to-clear, so no puppy we produce can be affected. See how this fits the rest of our breeding program and the ADRK standard we hold to.