Sorbitol dehydrogenase (SORD) deficiency
Clinical cases: Neurology
Background
A 23-year-old male presents with persistent peripheral limb weakness, which he’s experienced for more than 10 years. Nerve conduction studies and electromyography pointed to a demyelinating neuropathy with axonal features. Genome testing was negative for known pathogenic variants for hereditary peripheral neuropathy, and the patient is clinically diagnosed with Charcot-Marie-Tooth disease type 2. Upon more detailed genetic analysis, the patient is found to have two variants in SORD, which suggests the patient has SORD deficiency. Confirmatory testing performed at Mayo Clinic Laboratories, which uses gas chromatography/mass spectrometry to analyze the patient’s urine, was positive for SORD deficiency.
Teaching points
- The association between inherited changes in the SORD gene and peripheral neuropathy was first published in 2020, enabling the identification of SORD deficiency.
- When an autoimmune cause for neuropathy cannot be found, genetic evaluation of SORD can be considered.
- Mayo Clinic Laboratories was first-to-market with a urine test for SORD deficiency.
- Mayo Clinic Laboratories’ SORD test measures urine levels of sorbitol and xylitol, two sugar alcohols known to be elevated in people with SORD deficiency.
Key testing
SORD | Sorbitol and Xylitol, Quantitative, Random, Urine
- Turnaround time: 7 days
Learn more about how our testing protocol is useful in the diagnosis of sorbitol dehydrogenase (SORD) deficiency.
