Psychosine, a new predictive marker for Krabbe disease?

Written on Tuesday 3 June 2014

Krabbe disease is an illness due to a deficiency in galactocerebrosidase (GALC), an enzyme involved in the degradation of a major lipid constituent of myelin.

The predominant form of Krabbe disease is characterised by a progressive neurologic degradation from the age of 6 months, with death generally occuring before two years of age. The deficiency in GALC results in an accumulation of a complex lipid called psychosine.
More than 1.2 million newborns were tested for Krabbe disease in the State of New York using a newborn screening test measuring GALC activity in dried blood spots. Amongst these, four newborns were diagnosed as being carriers of the infantile form of Krabbe disease. Six other newborns at high risk of the developing the disease showed no symptoms for now.
The aim of the study was to determine whether psychosine can be a useful marker of the disease and its progression. The concentration of psychosine in dried blood spots was determined in different infant populations using a technology combining high performance liquid phase chromatography to mass spectometry. The following psychosine concentrations were measured:

  • 7 to 50 nanograms per milliliter of blood in patients with a known Krabbe disease
  • 23 à 73 nanograms per milliliter of blood in babies screened by the NY newborn screening and diagnosed as carriers of infantile Krabbe disease
  • 1,7 à 5,7 nanograms per milliliter of blood in asymptomatic newborns

In brief, psychosine concentrations measured in dried blood spots from patients with a confirmed pathology are at least four times higher than those of asymptomatic newborns. However, further studies are necessary to determine whether psychosine can indeed be used as a predictive marker of the disease and its progression in infants diagnosed by the newborn screening.

Illness: Krabbe disease
Samples: Dried blood spots from newborn
Study type: Diagnostic
Laboratory: Dr. Joseph J. Orsini Jr, New York State Department of Health, Wadsworth Center, Albany, NY, USA

Source : W.L. Chuang, J. Pacheco, X.K. Zhang, M.M. Martin, C.K. Biski, J.M. Keutzer, D.A. Wenger, M. Caggana, J.J. Orsini Jr. Determination of psychosine concentration in dried blood spots from newborns that were identified via newborn screening to be at risk for Krabbe disease. Clin Chim Acta. 2013, 419:73-6.

Scientific information provided in collaboration with the INIST-CNRS Institute, Institute for Scientific and Technical Information