J Clin Res Pediatr Endocrinol. 2024; 16(3): 361-366 | DOI: 10.4274/jcrpe.galenos.2022.2022-9-12

Mild Aromatic L-Amino Acid Decarboxylase Deficiency Causing Hypoketotic Hypoglycemia in a 4-year-old Girl

Merve Yoldaþ Çelik¹, Ebru Canda¹, Havva Yazýcý¹, Fehime Erdem¹, Ayþe Yüksel Yanbolu¹, Ayça Aykut², Asude Durmaz², Ahmet Anýk³, Sema Kalkan Uçar¹, Mahmut Çoker^1
1Ege University Faculty of Medicine, Department of Pediatrics, Clinic of Pediatric Metabolism and Nutrition, Ýzmir, Turkey
²Ege University Faculty of Medicine, Department of Medical Genetics, Ýzmir, Turkey
³Aydýn Adnan Menderes University Faculty of Medicine, Department of Pediatrics, Clinic of Pediatric Endocrinology, Aydýn, Turkey

Aromatic L-amino acid decarboxylase (AADC) deficiency is a disease in which neurological findings are dominant due to deficiencies in neurotransmitter synthesis. Hypoglycemia caused by autonomic dysfunction is one of the symptoms that may be encountered. Here we report a case of mild AADC deficiency presenting with hypoglycemia without any neurological signs. A 4-year-old girl presented with recurrent hypoglycemia. Her growth and development were normal. Plasma insulin and cortisol values were normal in the sample at the time of hypoglycemia. C8: 1-Carnitine elevation was detected in the acylcarnitine profile. A clinical exome panel was performed with the suggestion of a fatty acid oxidation defect. However, a homozygous variant in the DDC gene was detected. Furthermore, cerebrospinal fluid neurotransmitter analysis revealed low 5-hydroxyindolacetic acid and homovanillic acid and high 3-O-methyl-dopa and methyltetrahydrofolate (5 MTHF) consistent with AADC deficiency. Plasma AADC enzyme activity was low. The episodes of hypoglycemia were treated with uncooked cornstarch. This case suggests that AADC deficiency should be considered in some patients with hypoglycemia.

Keywords: Aromatic L-amino acid decarboxylase deficiency, AADC deficiency, hypoglycemia, neurotransmitter deficiency

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