Study of association between the HLA-DQB1*0602 and daytime sleepiness in non-narcoleptic individuals of the city of Sao Paulo

Abstract

Several studies have been conducted in order to understand the genetic factors that may be associated with sleep disorders and related phenotypes. Daytime sleepiness is a symptom commonly observed in patients with obstructive sleep apnea syndrome (OSAS) and narcolepsy, as well as in individuals submitted to sleep deprivation, a condition that has been constantly increasing in the current society. The allele DQB1 * 0602, which is located in the major histocompatibility complex (MHC), is present in approximately 95% of Caucasians with narcolepsy and is considered a genetic marker for this disorder. More recently, studies have shown that individuals who are not narcoleptic and DQB1*0602-positive have specific changes in sleep patterns, increased sleepiness and fatigue when subjected to sleep deprivation, suggesting that this allele may be associated with variability in the levels of daytime sleepiness observed in healthy subjects and patients with OSAS. In this context, the objectives of this study are: 1) determine the prevalence of the allele in a population based sample from São Paulo and 2) determine the association between the presence of this allele and parameters of daytime sleepiness in individuals with and without OSAS. A total of 1010 DNA samples from individuals from the Sao Paulo Epidemiologic Sleep Study (EPISONO) conducted in 2007 will be evaluated for the presence of the DQB1 * 0602, using the technique of Polymerase Chain Reaction (PCR), according to standard protocol . Understanding the genetic factors related to sleepiness is extremely important, since it may help prevent and early diagnose a condition increasingly common in the current society.