Previous studies have estimated an overall prevalence for narcolepsy between 15 and 70 cases per 100 000 inhabitants. We aimed to estimate the prevalence of narcolepsy in Catalunya (Catalonia), a north-east region of Spain (7 424 754 inhabitants), on 31 December 2014 by identifying all living subjects diagnosed with narcolepsy. First, we identified patients diagnosed by one of the 13 sleep, paediatric or neurological departments that perform tests regularly to diagnose narcolepsy. In a second phase, we searched for additional patients with narcolepsy in a clinical database of the primary health-care system. Clinical files were reviewed and narcolepsy diagnosis validated according to the Brighton Collaboration case definitions. Three hundred and twenty-five patients had a validated diagnosis of narcolepsy in the specialized centres (mean age: 44.6 years, range: 6-89; male: 60.3%; 85% with narcolepsy type 1), including 17.8% cases in Brighton, definition level 1, 62.5% in level 2, 15.4% in level 3 and 4.3% in level 4a. The overall prevalence for narcolepsy was 4.4; 3.7 for narcolepsy type 1 and 0.7 cases per 100 000 inhabitants for narcolepsy type 2. Fifty-six additional narcoleptic patients were identified in the primary health-care system, increasing the overall prevalence to 5.2 cases per 100 000 inhabitants. Prevalence rates for narcolepsy type 1 increased from childhood to adulthood, but in subjects aged more than 50 years there was a substantial drop in prevalence rates, suggesting the presence of a significant pool of undiagnosed cases in this population. Narcolepsy can be considered a rare neurological disorder in Catalunya.
Phenylketonuric (PKU) patients are a population at risk for sleep disorders due to deficits in neurotransmitter synthesis. We aimed to study the prevalence of sleep disorders in earlytreated PKU children and adolescents and assessed correlations with dopamine and serotonin status. We compared 32 PKU patients (16 females, 16 males; mean age 12 years), with a healthy control group of 32 subjects (16 females, 16 males; mean age 11.9 years). 19 PKU patients were under dietary treatment and 13 on tetrahydrobiopterin therapy. Concurrent phenylalanine (Phe), index of dietary control and variability in Phe in the last year, tyrosine, tryptophan, prolactin, and ferritin in plasma, platelet serotonin concentration, and melatonin, homovanillic and 5-hydroxyindoleacetic acid excretion in urine were analyzed. Sleep was assessed using Bruni's Sleep Disturbance Scale for Children. Sleep disorders were similar in both groups, 15.6% in control group and 12.5% in PKU group. In PKU patients, no correlations were found with peripheral biomarkers of neurotransmitter synthesis nor different Phe parameters, 43.3% had low melatonin excretion and 43.8% low platelet serotonin concentrations. Despite melatonin and serotonin deficits in early-treated PKU patients, the prevalence of sleep disorders is similar to that of the general population.
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