Transient lower oesophageal sphincter relaxation and mechanisms of gastrooesophageal reflux in twins discordant for gastrooesophageal reflux symptoms

P.19 TRANSIENT LOWER OESOPHAGEAL SPHINCTER RELAXATION AND MECHANISMS OF GASTROOESOPHAGEAL REFLUX IN TWINS DISCORDANT FOR GASTROOESOPHAGEAL REFLUX SYMPTOMS P. Iovino ∗,1, I. Mohammed2, R. Annggiansah 3, A. Anngiansah 3 , F. Cherkas 3, T. Spector3, N. Trudgill2 1Università Federico II, Napoli; 2Sandwell General Hospital, Birmingham; 3St Thomas Hospital, London Background and aim: Transient Lower Oesophageal Sphincter Relaxation (TLOSR) is the most frequent mechanism among several mechanical patterns associated with reflux episodes. The aim of this study is to investigate TLOSR in twin pairs who are discordant for gastrooesophageal reflux disease (GORD) symptoms, i.e. only one of the pair has GORD symptoms to establish whether differences in TLOSR may contribute to the aetiology of GORD. Material and methods: 4 monozygotic (MZ) and 12 dizygotic (DZ) twin pairs, who were repeatedly discordant for GORD symptoms over 2 years, were studied. LOS function using a sleeve sensor and oesophageal pH were monitored for 30 mins before and 60 mins after a 300 mls (1200 kcal) lipid meal. Results: MZ twins were aged mean 63 (range 53-75) yrs and DZ twins 57 (44-74) years. TLOSR frequency increased from 1(0-2) to 2.5 (1-8) per hour post-prandially (p= 0.001) in the symptomatic twins and from 0 (0-2) to 3(1-6) post-prandially in the asymptomatic twins (Median (range), p=0.001). Comparison between groups revealed that there was no difference in pre-prandial and post prandial TLOSR frequency. However no pre prandial TLOSR were associated with acidic reflux (pH<4) compared with 38% of post-prandial TLOSR. Acid reflux episodes (pH<4) increased post-prandiallyin both symptomatic and asymptomatic twins, but there was no differences between the groups in pre or post-prandial acid reflux episode frequency or total post-prandial acid exposure (symptomatic twins median 11 (range 0-1051)s, asymptomatic twins 4(0-487)s (p=0.4). Moreover preprandial LOS pressure of 13 (4-29) mmHg fell to 8 (2-13)after the meal (p= 0.0001). No difference was found in basal and post prandial lower esophageal sphincter pressure readings between asymptomatic and symptomatic twins (p=0.2). Conclusions: There was no difference in pre and post prandial TLOSR and in LOS pressure in twins discordant for GORD symptoms. # A. Oesophagus - 1. GER