Association of P10L Polymorphism in Melanopsin Gene with Chronic Insomnia in Mexicans

• Published in: International journal of environmental research and public health 2021-01, Vol.18 (2), p.571
• Main Authors: Gutiérrez-Amavizca, Bianca Ethel, Prado Montes de Oca, Ernesto, Gutiérrez-Amavizca, Jaime Paul, Castro, Oscar David, Ruíz-Marquez, Cesar Heriberto, Perez Conde-Andreu, Kricel, Pérez Calderón, Ricardo, Aguirre Ramírez, Marisela, Pérez-León, Jorge Alberto
• Format: Article
• Language: English
• Subjects: Alleles; Body mass index; Case-Control Studies; Confidence intervals; Drowsiness; Drug abuse; Etiology; Gene polymorphism; Genetic analysis; Genotype & phenotype; Genotypes; Haplotypes; Homeostasis; Humans; Insomnia; Melanopsin; Mental disorders; Mutation; Obesity; Overweight; Pilot Projects; Polymerase chain reaction; Polymorphism; Population studies; Questionnaires; Restriction fragment length polymorphism; Rod Opsins; Seasonal affective disorder; Single-nucleotide polymorphism; Sleep; Sleep and wakefulness; Sleep disorders; Sleep Initiation and Maintenance Disorders - genetics; Sleepiness; Statistical methods
• ISSN: 1660-4601; 1661-7827; 1660-4601
• DOI: 10.3390/ijerph18020571

The aim of this pilot study was to determine the association of the P10L (rs2675703) polymorphism of the gene with chronic insomnia in uncertain etiology in a Mexican population. A case control study was performed including 98 healthy subjects and 29 individuals with chronic insomnia not related to mental disorders, medical condition, medication or substance abuse. Samples were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Genetic analyses showed that the T allele of P10L increased risk to chronic insomnia in a dominant model ( = 1 ×10 ; odds ratio (OR) = 9.37, CI = 8.18-335.66, Kelsey statistical power (KSP) = 99.9%), and in a recessive model ( = 7.5 × 10 , OR = 9.37, KSP = 99.3%, CI = 2.7-34.29). In the insomnia group, we did not find a correlation between genotypes and chronotype ( = 0.219 Fisher's exact test), severity of chronic insomnia using ISI score ( = 0.082 Fisher's exact test) and ESS score ( ˃ 0.999 Fisher's exact test). However, evening chronotype was correlated to daytime sleepiness severity, individuals with an eveningness chronotype had more severe drowsiness according to their insomnia severity index (ISI) score ( = 0.021 Fisher's exact test) and Epworth sleepiness scale (ESS) score ( = 0.015 Fisher's exact test) than the morningness and intermediate chronotype. We demonstrated that the T allele of the P10L polymorphism in the gene is associated with chronic insomnia in Mexicans. We suggest the need to conduct larger studies in different ethnic populations to test the probable association and function of P10L and other SNPs in the gene and in the onset of chronic insomnia.