Congenital error of metabolism with autosomal recessive inheritance caused by a deficiency of L-2-hydroxyglutarate dehydrogenase (L2HGDH). L-2-hydroxyglutaric acid accumulates and produces a progressive leukoencephalopathy with neurological signs. It has been described in the Staffordshire Bull Terrier, Yorkshire Terrier and West Highland White Terrier, as well as in the domestic cat, with different causal variants depending on the species and breed.

Described in Staffordshire Bull Terrier, Yorkshire Terrier and West Highland White Terrier (OMIA:001371-9615). In the cat it has been described in a domestic long-haired cat (2021) and a domestic short-haired cat (2023), not in pure breeds. No reliable carrier frequencies per breed are available: limited data.

- Ataxia and gait abnormalities\n- Tremors and incoordination\n- Seizures and paroxysmal episodes\n- Behavioural changes, disorientation and cognitive decline\n- Cerebellar and pyramidal signs\n- On MRI: symmetrical white matter lesions (leukoencephalopathy)\n- In urine: markedly elevated L-2-hydroxyglutaric acid\n- Not painful

The first canine cases were described in Staffordshire Bull Terriers (Abramson et al., 2003). Penderis et al. (2007) identified the causal mutation in that breed by sequencing L2HGDH. Sanchez-Masian et al. (2012) and Farias et al. (2012) described a different mutation, in the start codon, in Yorkshire Terriers. In the cat, Christen et al. (2021) described the first causal variant in a domestic long-haired cat and Christen et al. (2023) a second one in a domestic short-haired cat.

- Test breeding animals of the affected breeds before breeding.\n- Do not mate two carriers together.\n- A carrier may be mated to a clear animal; test the offspring intended for breeding.\n- Choose the test appropriate to the breed: the Staffordshire Bull Terrier variant and the Yorkshire Terrier variant are different.\n- In cats, the evidence is limited and based on isolated cases.

The causal variant differs between breeds, so the corresponding test must be selected and results must not be extrapolated between them. The cat has its own variants. The diagnosis relies on the elevation of L-2-hydroxyglutaric acid in urine and is confirmed by genetics. There is no specific treatment; management is symptomatic and supportive.

1. Penderis J, Calvin J, Abramson C, et al. L-2-hydroxyglutaric aciduria: characterisation of the molecular defect in a spontaneous canine model. J Med Genet. 2007;44(5):334-340. PMID: 17475916.
2. Sanchez-Masian DF, Artuch R, Mascort J, et al. L-2-hydroxyglutaric aciduria in two female Yorkshire terriers. J Am Anim Hosp Assoc. 2012;48(5):366-371. PMID: 22843824.
3. Farias FH, Zeng R, Johnson GS, et al. A L2HGDH initiator methionine codon mutation in a Yorkshire terrier with L-2-hydroxyglutaric aciduria. BMC Vet Res. 2012;8:124. PMID: 22834903.
4. Christen M, Rütgen BC, et al. L2HGDH Missense Variant in a Cat with L-2-Hydroxyglutaric Aciduria. Genes (Basel). 2021;12(5):682. PMID: 34062805.
5. Christen M, et al. A novel missense variant in the L2HGDH gene in a cat with L-2-hydroxyglutaric aciduria and multicystic cerebral lesions. J Vet Intern Med. 2023;37(2). PMID: 36880414.
6. OMIA:001371-9615. L-2-hydroxyglutaricacidemia in Canis lupus familiaris. https://omia.org/OMIA001371/9615/
7. OMIA:001371-9685. L-2-hydroxyglutaricacidemia in Felis catus. https://omia.org/OMIA001371/9685/