Search results for "Birth Certificates"

Season of birth effect in narcolepsy

2003

The causes of narcolepsy are unknown.1 Genetic factors such as positivity for HLA DR2 or certain genotypes of tumor necrosis factor–alpha or the orexin gene only explain a fraction of the risk. A season of birth effect has been observed in numerous studies for schizophrenia and bipolar disorder with a 10% excess of birth in winter and spring.2 Among the underlying factors discussed are infectious agents as well as seasonal variations in nutrition, light effects, and toxins.2 Most recently, the vitamin D hypothesis has been revisited.3 The production of vitamin D is associated with exposure to sunlight and the active 1,25 dihydroxyvitamin D3 is a potent modulator of immune functions,4 a dysf…