Effectiveness of Medium-Chain Triglyceride Oil Therapy in Two Japanese Citrin-Deficient Siblings: Evaluation Using Oral Glucose Tolerance Tests.

Citrin deficiency, an inherited defect of the liver-type mitochondrial aspartate/glutamate carrier isoform (citrin), may cause impairment of glycolysis because of an increase in the cytosolic NADH/NAD+ ratio. We report a Japanese boy whose main complaint was recurrent hypoglycemic episodes. He was suspected as having citrin deficiency because of his peculiar preference for protein- and fat-rich food. His young sister also had a similar food preference. Both siblings were diagnosed with citrin deficiency by genetic analysis. The brother and sister underwent an oral glucose tolerance test (OGTT) at 10 and 7 yr of age, respectively. Blood glucose, ammonia, lactic acid, pyruvic acid, and insulin levels were monitored before starting the test, and then every 30 min. During this test, they maintained blood glucose levels until 180 min. At 210 min, they experienced vomiting, feeling ill, and decreased blood glucose levels (2.9 and 2.8 mmol/l in the brother and sister, respectively). The sister and brother recovered uneventfully by intravenous glucose injection. In a second OGTT, 4 months after medium-chain triglyceride (MCT) oil supplementation, they had no major symptoms and normal glucose levels were maintained, even after 240 min. Additionally, after MCT oil therapy, their food preference slightly changed as they started eating more carbohydrates. Our OGTT data suggest excess carbohydrate intake has adverse consequences in patients with citrin deficiency, including hypoglycemia after a few hours. MCT oil therapy may be effective in preventing such hypoglycemia and improving metabolic derangement, even during the so-called apparently healthy period.

Propranolol as an alternative treatment option for pediatric lymphatic malformation.

Lymphatic malformation (LM), which was previously termed lymphangioma, is a rare congenital malformation of the lymphatic system and its treatment is still challenging. Propranolol (beta blocker) has been recently developed as a first-line treatment of infantile hemangioma. Our study aimed to assess the effect of propranolol on pediatric LM and the relationship between its effectiveness and vascular endothelial growth factor (VEGF) family members (VEGF-A, C and D). Six Japanese patients with LM (age range: 10 months-19 years old; 2 macrocystic, 2 microcystic and 2 combined type) were enrolled. Oral propranolol was administered at 2 mg/kg/day. The efficacy of propranolol for LM was evaluated by the rate of volume change as calculated from MRI imaging and by symptomatic improvement. In all patients, there were no significant side effects. Patients 3 and 5 were classified as objective responders with tumor volume reduction of 30.6% and 22.9%, respectively, at 24 weeks. Patient 1 showed 8% tumor volume reduction and patient 6 showed symptomatic improvement, hence, both were classified as minimal responders. The other two patients were classified as non-responders. Plasma VEGF-A, C, and D levels were significantly higher in the LM group than in the controls (all P < 0.01 by Mann-Whitney test). VEGF-A and D levels at 24 weeks were significantly lower than those at pre-treatment (P = 0.031, 0.047 by Wilcoxon matched pairs test). Though further trials with this treatment must be carried out, we propose that propranolol may be an alternative therapy option for intractable LM.