Mild Aromatic L-Amino Acid Decarboxylase Deficiency: As A Reason For Hypoketotic Hypoglycemia In A 4-Year-Old Girl.

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 mild AADC deficiency presenting with hypoglycemia without a neurological sign. 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. The C8:1-Carnitine elevation was detected in the acylcarnitine profile. The clinic exome panel was performed with the suggestion of a fatty acid oxidation defect. However, a homozygous variant in the DDC gene was detected. On top of that, CSF neurotransmitter analysis revealed low 5-hydroxy indol acetic ( 5 HIAA ) and homovanillic acid ( HVA ) 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. Our case emphasizes that AADC deficiency should be considered in patients with hypoglycemia.