Narcolepsy genetic variants associated with sleep efficiency in a community dwelling older cohort

Abstract Narcolepsy type I (NT1) is a life-long debilitating autoimmune neurological condition characterised by excessive daytime sleepiness (EDS); the only symptom universal to all patients. Issues regarding sleep efficiency is also prevalent in individuals with NT1, however it remains relatively understudied due to the difficulty in measuring the effect. Genetic traits have shown to predispose an individual to NT1 and while HLA-DQB1 * 06:02 remains the most impactful genetic risk factor additional genes that contribute to immune cell processing have also been identified. In this retrospective study we impute 13 non-MHC narcolepsy associated single nucleotide polymorphisms (SNPs) from 1,558 non-pathological elderly volunteers who have been followed for up to a 24-year period to determine the association with sleep efficiency. Utilising a healthy cohort allows us to independently assess the potential contribution of each SNP on the impact of the sleep cycle disruption. We observed significant associations between SNPs and various elements of the sleep process; however, the main findings were the associations with disturbed night sleep (DNS). We observed an association with rs10915020 and rs1551570 with an increased number of wake episodes during the night, conversely rs2859998 and rs2834168 showed a protective effect—reducing the frequency of nighttime disturbances. While the association with NT1 and DNS has long been established, this is the first investigation that attributes elements of DNS to the genetic profile of the patient. This suggests that the issues with sleep efficiency reported by patients may be due to genetic predispositions and supports the variation seen in the co-morbidities associated with the condition.