Materials and methods: Revision of the clinical files of all patients under the age of 18-year-old with confirmed narcolepsy type 1 (meet MSLT criteria) or suspected (hypersomnia and cataplexy, without typical MSLT), followed in a tertiary hospital during the first half of 2017. Results: A total of 13 patients were enrolled (9 male, 4 female), with a mean age at the first visit of 11 year-old (minimum 6, maximum 15). The mean time from the beginning of the symptoms to the first visit was 2.5 years. Symptoms appeared under the age of 5 year-old in 3. All the patients had hypersomnia as the first symptom, 7 of them with associated cata- plexy. On average, cataplexy appeared 2.5 years after hypersomnia in 6 cases. Besides the typical transient loss of tonus with the emotions, 1 pa- tient had facial hypotonia and another presented head drop and myoc- lonus of the upper limbs. Five patients reported hypnagogic hallucinations. Decrease in school performance was seen in 7, sudden weight gain in 7 and neuropsychiatric symptoms in 10. Polysomnography showed decreased sleep latency in 11 patients, decreased REM latency in 7, disrupted sleep in 11, REM sleep without atonia in 4 and periodic limb movements in 6. MSLT confirmed the diagnosis in 11 patients, 2 of them only after repeating the exam. Two patients dont fulfilled MSLT diagnostic criteria because no SOREMPs were observed but both had typical symptoms and the HLA DQB1*0602 was positive. Conclusions: In our case series, the mean time from the beginning of the symptoms to the first visit was lower than the reported in adult series. This is probably related to the impact of the disease in school performance. Cataplexy appears to be more valorized than hypersomnia, as these patients are referred earlier. In children, cataplexy may present as facial hypotonia and display positive motor phenomena. Although nonspecific, some PSG abnormalities are common. The diagnosis of narcolepsy can be difficult and sometimes requires serial sleep studies, because the diagnostic feature of  2 SOREMPs is not consistently present in the early stages of the disorder. Test for HLA DQB1*0602 can be helpful in these cases. Sleep Breathing Disorders GENETIC, CLINICAL AND TREATMENT HETEROGENEITY OF THREE PATIENTS WITH CONGENITAL CENTRAL HYPOVENTILATION SYNDROME M. Rios 1 , N. Madureira 2 , T. Barbosa 1 , M.G. Reis 1 , L. Morais 1 , A. Ramos 1 . 1 Pulmonology Unit of Pediatric Department, Centro Materno- Infantil do Norte, Centro Hospitalar do Porto, Porto, Portugal; 2 Pediatric Pulmonology Unit, Hospital Pedi atrico, Centro Hospitalar e Universit ario de Coimbra, Coimbra, Portugal Introduction: Congenital central hypoventilation syndrome (CCHS) is a rare disorder characterized by sleep-related hypoventilation predomi- nantly during NREM sleep. Its caused by mutations in PHOX2B, in most cases due to heterozygous expansions of a 20-polyalanine tract on exon 3 (PARMs mutations). Usually the first symptoms appear in the neonatal period, but few cases have a late-onset (LO-CHS). Material and methods: describe the clinical features, polysomnography (PSG) reports, genetic defects and treatment of 3 patients with CCHS. Results: Case 1 e a 13-year-old male who had neonatal central apneas leading to mechanical ventilation during the first 20 days of life. Ater extubation he presented hypercapnia and hypoxemia predominantly during sleep. PSG showed reduced flow, hypercapnia and hypoxemia. Genetic testing for PHOX2B revealed a short PARM mutation 20/25 which confirmed the diagnosis of CCHS. He is being treated with non-invasive ventilation (NIV) since neonatal period. His growth is normal and no cognitive deficits were found despite poor school performance. Case 2 e a 9-year-old male who began mechanical ventilation 20 minutes after birth because of apneas. He was submitted to tracheostomy at 2- month-old due to ventilation dependency that currently maintains. He also presented macrocephaly with skull deformation and facial dys- morphism, ventricular septal defect and pulmonary stenosis, right bundle branch block, epilepsy, cognitive delay, strabismus, eating difficulties and poor weight gain. Genetic testing was positive for a short PARM mutation 20/26 in PHOX2B that confirmed the diagnosis of CCHS. Superior vena cava syndrome due to thrombosis in central venous catheter was diagnosed at 4 years old. Case 3 e a 8-year-old female admitted to the intensive care at 9,11 and 13 months suffering from severe hypercapnic respiratory failure during viral respiratory infections. She had hypercapnia during sleep that improved with wakefulness. CCHS was confirmed genetically (heterozygous inser- tion of an adenine at position 23, leading to a premature stop codon in exon 1 of the PHOX2B gene). Hypoventilation was observed by PSG, with no autonomic response to declining oxygen or increasing carbon dioxide values. The patient has been on NIV during sleep since 13 months of age, showing good growth and neurocognitive development. Conclusions: In patients with shorter PARM mutations like 20/25 and 20/ 26 clinical abnormalities tend to be mild. Despite this, patient 2 has a more severe phenotype. Autonomic dysfunction in vasculature that can occur in CCHS may have precipitated thrombosis in this case. A greater awareness is required to diagnose LO-CHS that should be suspected in the presence of severe hypercapnia during respiratory infections and significant difference in CO2 between sleep and wakefulness. LO-CHS cases are usually related to PHOX2B PARM 20/24 or 20/25 genotypes. Our patient with LO-CHS has a mutation not previously described. Early diagnosis of CCHS and institution of adequate ventilatory support are crucial. Ventilation by tracheostomy is considered the safest way to manage these patients, but NIV with a mask has been proved effective as illustrated by the two children presented. REM Behavior Disorders TRODAT SPECT IN IDIOPATHIC RBD PATIENTS G. Rizzo. SONOLAB, Institute of Clinical Neurophysiology, Porto Alegre, Brazil Introduction: TRODAT is a marker that selectively binds to the pre- synaptic dopamine receptors (DAT) present in our brain. The loss of DAT correlates with that of dopaminergic neurons, being demonstrated in a very sensitive way in the images obtained by the examination, even in the initial phases of the condition. The reduction of these receptors density, in turn, is associated with the severity and progression of Parkinson Disease. On the other hand, normal images rule out the hypothesis of this disease. Materials and methods: We have studied and selected retrospectively 6 patients who presented with clinical and polysomnographic diagnosis of IRBD, on treatment or not, during last year, to be submitted to a tomo- graphic perfusional scintigraphy with TRODAT. Results: 5 from 6 patients (84%) have abnormal test. Conclusions: TRODAT-1 is a tropane derivative which, when labeled with meta-stable Technetium 99 (99mTc) crosses the blood brain barrier, has a high affinity for DAT and is captured by SPECT mode scintigraphy, pro- ducing a site-specific image of the DAT. It offers great advantages compared to other tracers, because it presents the same efficiency with much lower cost. The other tracers use isotopes such as [123I] for SPECT and [11C] and [18F] for PET, which have little availability in Brazil and cost at least 10 times higher when compared to 99mTc. The reduction in DAT density occurs even before the onset of PD symp- toms, since there is a 40 to 60% reduction in dopaminergic activity (uptake of DAT tracers) when the first symptoms appear and, with the evolution of the disease, the levels of uptake decrease by up to 90%. It is for this reason that the concentration of DAT in the evaluation of the loss of dopaminergic neurons in the striatum, more specifically in the putamen, has been shown to be a useful parameter both in the early diagnosis of PD and in the dif- ferential diagnosis with other diseases that induce extrapyramidal symp- toms. With this study we have tried to reinforce IRBD as a marker of neurodegenerative disease. Sleep Breathing Disorders CASE OF OBSTRUCTIVE SLEEP APNEA WITH SLEEP WALKING S.H. Ro , Y.H. Um, S.C. Hong. Department of Psychiatry, St. Vincent Hospital, College of Medicine, The Catholic University of Korea, Suwon city, Republic of Korea Introduction: Obstructive sleep apnea is a frequently diagnosed sleep disorder in general population. It can occur in any age groups, and is related to increases in other medical and sleep comorbidities. Sleep walking, which is categorized as NREM-related parasomnia, is usually considered a normal developmental sleep phenomenon in children. But it can also occur precipitating factors such as sleep disorders causing frequent arousal, obstructive sleep apnea (OSA). Abstracts / Sleep Medicine 40 (2017) e186ee363 e279