A rare cause of severe diarrhoea diagnosed by urine metabolic screening: aromatic L-amino acid decarboxylase deficiency.
A 15-year-old Chinese male with infantile-onset hypotonia, developmental delay, ptosis, and oculogyric episodes presented with a history of chronic diarrhoea since the age of 5 years. At presentation, he had an exacerbation of diarrhoeal symptoms resulting in dehydration and malnutrition with a concurrent severe chest infection. In view of his infantile-onset hypotonia, oculogyric crises, and protracted diarrhoea, an autonomic disturbance related to neurotransmitters was suspected. Urine organic acid profiling was compatible with aromatic L-amino acid decarboxylase deficiency. The diagnosis was confirmed based on cerebrospinal fluid analysis and genetic mutation analysis. The patient was treated with a combination of bromocriptine, selegiline, and pyridoxine; a satisfactory reduction in diarrhoea ensued. Our report highlights the importance of urine organic acid screening in infantile-onset hypotonia, especially when accompanied by oculogyric crises, and severe diarrhoea which could manifest as a result of autonomic disturbance.
Department of Paediatrics and Adolescent Medicine, Caritas Medical Centre, Shamshuipo, Hong Kong.
L K
LK
Lee
Department of Paediatrics and Adolescent Medicine, Caritas Medical Centre, Shamshuipo, Hong Kong.
K M
KM
Cheung
Department of Paediatrics and Adolescent Medicine, Caritas Medical Centre, Shamshuipo, Hong Kong.
W W
WW
Cheng
Department of Paediatrics and Adolescent Medicine, Caritas Medical Centre, Shamshuipo, Hong Kong.
C H
CH
Ko
Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Laichikok, Hong Kong.
Hencher H C
HH
Lee
Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Laichikok, Hong Kong.
C K
CK
Ching
Chemical Pathology Laboratory, Department of Pathology, Princess Margaret Hospital, Laichikok, Hong Kong.
Chloe  M
C
Mak
D000293:Adolescent; D000592:Amino Acid Metabolism, Inborn Errors / Q000150:complications / Q000175:diagnosis*; D001142:Aromatic-L-Amino-Acid Decarboxylases / Q000172:deficiency*; D002658:Developmental Disabilities / Q000150:complications; D003967:Diarrhea / Q000209:etiology*; D006801:Humans; D008297:Male; D009123:Muscle Hypotonia / Q000150:complications / Q000151:congenital; D015835:Ocular Motility Disorders / Q000150:complications / Q000151:congenital; D012720:Severity of Illness Index
D001142:Aromatic-L-Amino-Acid Decarboxylases
Aromatic-L-amino-acid decarboxylases/deficiency; Diarrhea