Effects of GBA1 Variants and Prenatal Exposition on the Glucosylsphingosine (Lyso-Gb1) Levels in Gaucher Disease Carriers.

Gaucher disease (GD) is a lysosomal lipid storage disorder caused by β-glucocerebrosidase (encoded by GBA1 gene) activity deficiency, resulting in the accumulation of glucosylceramide (Gb1) and its deacylated metabolite glucosylsphingosine (lyso-Gb1). Lyso-Gb1 has been studied previously and proved to be a sensitive biomarker, distinguishing patients with GD from carriers and healthy subjects. It was shown that its level corresponds with β-glucocerebrosidase activity, thus it remains unknown as to why carriers have slightly higher lyso-Gb1 level than healthy population. This is the first report on lyso-Gb1 levels describing representative cohort of GD carriers. Our data of 48 GD carriers, including three newborns, indicated that there are significant differences in lyso-Gb1 levels between carriers having a GD-affected mother and a healthy mother (11.53 and 8.45, respectively, p = 0.00077), and between carriers of the L483P GBA1 variant and carriers of other GBA1 pathogenic variants (9.85 and 7.03, respectively, p = 0.07). Through analysing our unique data of three newborns whose mothers are patients with GD, we also found that lyso-Gb1 is most probably transferred to the foetus via placenta.