Tohoku J. Exp. Med., 2016 December, 240(4), 323-328.

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

HIROKI OTSUKA,^1,2 HIDEO SASAI,^1,2 ELSAYED ABDELKREEM,^1,3 NORIO KAWAMOTO,¹ MINAKO KAWAMOTO,¹ TOSHIYA KAMIYA,⁴ YASUO TANIMOTO,⁴ ATSUO KIKUCHI,⁵ SHIGEO KURE,⁵ CHIKAHIKO NUMAKURA,⁶ KIYOSHI HAYASAKA⁶ and TOSHIYUKI FUKAO^1,2

¹Department of Pediatrics, Graduate School of Medicine, Gifu University, Gifu, Gifu, Japan
²Division of Clinical Genetics, Gifu University Hospital, Gifu, Gifu, Japan
³Department of Pediatrics, Faculty of Medicine, Sohag University, Nasser, Sohag, Egypt
⁴Department of Pediatrics, JA Mie Kouseiren Matsusaka Central General Hospital, Matsusaka, Mie, Japan
⁵Department of Pediatrics, Tohoku University School of Medicine, Sendai, Miyagi, Japan
⁶Department of Pediatrics, Yamagata University School of Medicine, Yamagata, Yamagata, Japan

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.

keywords —— citrin deficiency; food preference; hypoglycemia; medium-chain triglyceride; oral glucose tolerance test

© 2016 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2016, 240, 323-328

Correspondence: Toshiyuki Fukao, Department of Pediatrics, Graduate School of Medicine, Gifu University, Yanagido 1-1 Gifu, Gifu 501-1194, Japan.

e-mail: toshi-gif@umin.net