Abstract for presentation at The Australian and New Zealand Association of Neurologists Annual Scientific Meeting 2007

Introduction: MELAS syndrome is a multisystem disorder that is associated with a point mutation in the tRNALeu gene in mitochondrial DNA (MELAS 3243A>G). Affected patients often suffer from gastrointestinal (GI) symptoms such as constipation and abdominal pain. GI dysmotility is likely to be an important contributing factor to these symptoms but this aspect has received little attention.
Aim: To characterize alterations in gastric emptying (GE) and in colonic transit (CT) and their interrelationships, in patients with MELAS syndrome.
Methods: Six patients (4F, 43+/-16 yrs) with the MELAS 3243A>G point mutation and without organic GI disease underwent dual phase GI tract scintigraphy, concurrently assessing solid (99m-Tc sulfur colloid) and liquid (67-Ga DTPA) GE and CT. Solid and liquid gastric half-emptying time (t1/2) as well as % colon activity retained at 24, 48, 72 and 96 hrs after the radiolabelled meal (422 kcal) were compared to laboratory reference values.
Results: All patients displayed abnormalities in GE and/or CT. For GE, median solid t1/2 was 122 min and liquid t1/2 was 84 min. Five (83%) patients exhibited delayed GE; one had both delayed solid GE and liquid GE, one delayed solid GE only and three delayed liqid GE only. CT data are shown in Table. Four patients had both abnormal GE and abnormal CT, one had abnormal CT only and one had abnormal GE only. There was no correlation between the presence of delayed GE and delayed CT.
Conclusion: GI motor dysfunction is a prominent feature of patients with MELAS. Widespread delay in gut transit is common, with both delayed GE and delayed CT occuring with equal frequency.
These findings help explain the origin of GI symptoms in MELAS.