Implication of Apolipoprotein E gene variants in pediatric-onset multiple sclerosis: Possible association with disease susceptibility and its clinical characteristics, in a Hellenic cohort.

Background: Apolipoprotein E (ApoE) plays a major role in lipid homeostasis and myelination in the central nervous system. Although ApoE gene variants have been linked with cognitive impairment in the setting of Multiple sclerosis (MS), no association with disease susceptibility was found, while similar studies in pediatric-onset MS (POMS) are limited.

Objective: This study aims to explore the role of ApoE gene variants in the POMS susceptibility of a Hellenic cohort and any association with disease features.

Methods: 112 POMS, fulfilling the revised IPMSSG 2013 criteria, 391 adult-onset MS (AOMS) and 200 healthy controls (HCs), were enrolled. After DNA extraction, ApoE genotyping was performed by a polymerase chain reaction and sequence-specific-oligonucleotide technique.

Results: ApoE2/E3 genotype and ApoE2 allele were found to be significantly more frequent among POMS patients compared to HCs [(20.5% vs 11 %, OR [95 %]: 2.1 (1.1-4.0), p = 0.03)], and [(11% vs 5.3 %, OR [95 %]: 2.3 (1.2-4.1), p = 0.01)], respectively. Additionally, significantly lower frequencies of the ApoE3/E3 genotype and the ApoE3 allele were observed in POMS patients compared to HCs (59.8% vs 79 %, OR [95 %]:0.40 (0.24-0.65), p = 0.0005 and 79% vs 89 % 0.46, OR [95 %]: (0.30-0.73), p = 0.001)], respectively.

Conclusions: The ApoE2 allele may represent a novel risk factor for POMS development.