Krabbe disease
Krabbe Disease: Psychosine Monitoring
Krabbe Disease: Psychosine Monitoring
This test measures psychosine (galactosylsphingosine), a substrate of the galactocerebrosidase (GALC) enzyme, and can be used as a biomarker for diagnosis and treatment monitoring in patients with Krabbe disease. Psychosine may also be elevated in atypical Krabbe disease due to Saposin A deficiency caused by variants in the PSAP gene.
Please note that if this test is being measured as a second-tier test for newborn screening, the results will be delivered within 2 business days.
Clinical Information
Krabbe disease is caused by a deficiency of the enzyme galactocerebrosidase (GALC), which is required for the degradation of psychosine (galactosylsphingosine). Accumulation of psychosine due to GALC deficiency leads to demyelination and neurodegeneration. Patients with infantile Krabbe disease present with irritability, muscle weakness or stiffness, fevers, feeding difficulties, spasticity, myoclonic seizures, hearing and vision loss, and progressive decline in mental and motor skills. Juvenile and late-onset forms of Krabbe disease also occur. The severe infantile form typically presents between 3 and 6 months of age with rapidly progressive neurodegeneration, muscle rigidity, seizures, irritability, vomiting, and blindness and/or deafness. Approximately 10–15% of patients exhibit a milder, later-onset phenotype, characterized by weakness or stiffness, ataxia, vision loss, and varying degrees of intellectual regression.
Technical Information
Psychosine levels are measured using liquid chromatography-tandem mass spectrometry (LC-MS/MS).
Specimen Requirements
Dried blood spots (DBS) are the accepted sample type for this test. Approximately 75 uL of blood should be applied to each of the five circles on filter paper dried blood spot card. Allow blood to dry for at least 4 hours before shipping.
Transport Instructions
Ship DBS card at ambient temperature.
Connect With Our Experts
Call 1-800-473-9411 to speak with our team of laboratory genetic counselors for questions or additional information.
Robin Fletcher, MS, CGC
Falecia Thomas, MS, CGC
Alex Finley, MS, CGC