Inborn error of gamma-aminobutyric acid (GABA) metabolism due to succinic semialdehyde dehydrogenase (ALDH5A1/SSADH) deficiency. It produces accumulation of succinic semialdehyde and GHB (gamma-hydroxybutyric acid) with neurotoxicity. Affected dogs show progressive neurological signs of early onset. It is inherited in a recessive manner.

Specific to the Saluki. It is a very rare disease; no reliable carrier frequencies in the general population are published.

- Progressive ataxia of early onset\n- Seizures\n- Lethargy and somnolence\n- Behavioural alterations\n- Progressive neurological deficits\n- Accumulation of succinic semialdehyde and GHB in biological fluids

SSADH deficiency was described in the Saluki as a canine analogue of human ALDH5A1 deficiency. The molecular basis was associated with a variant of the ALDH5A1 gene that reduces or abolishes enzyme activity, with characteristic organic acid biochemistry. The characterisation was based on the clinical and biochemical parallelism with the human disease, which allowed a genetic carrier test.

- Test breeding animals before mating\n- Do not cross two carriers: 25 % risk of affected homozygotes\n- A carrier can be crossed with a clear animal; test offspring intended for breeding\n- Avoid spreading the allele to lines where it does not exist\n- In lines with a history of early neurological signs, prioritise testing

Differential diagnosis with other hereditary metabolic encephalopathies and with acquired causes of ataxia and seizures. Organic acid biochemistry and the neurotransmission profile (elevated GHB) guide the diagnosis; the genetic test confirms carrier status. There is no curative treatment; management is supportive.

1. Vernau KM, Struys E, Letko A, et al. A missense variant in ALDH5A1 associated with canine succinic semialdehyde dehydrogenase deficiency (SSADHD) in the Saluki dog. Genes (Basel) 2020;11(9):1033. PMID: 32887425
2. Cocostîrc V, Paștiu AI, Pusta DL. An overview of canine inherited neurological disorders with known causal variants. Animals (Basel) 2023;13:3568. PMID: 38003185
3. OMIA:002250-9615 (ALDH5A1). https://omia.org/OMIA002250/9615/