A rare cause of severe diarrhoea diagnosed by urine metabolic screening: aromatic L-amino acid decarboxylase deficiency

Hong Kong Med J. 2014 Apr;20(2):161-4. doi: 10.12809/hkmj133922.

Abstract

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.

Keywords: Aromatic-L-amino-acid decarboxylases/deficiency; Diarrhea.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Amino Acid Metabolism, Inborn Errors / complications
  • Amino Acid Metabolism, Inborn Errors / diagnosis*
  • Aromatic-L-Amino-Acid Decarboxylases / deficiency*
  • Developmental Disabilities / complications
  • Diarrhea / etiology*
  • Humans
  • Male
  • Muscle Hypotonia / complications
  • Muscle Hypotonia / congenital
  • Ocular Motility Disorders / complications
  • Ocular Motility Disorders / congenital
  • Severity of Illness Index

Substances

  • Aromatic-L-Amino-Acid Decarboxylases

Supplementary concepts

  • Aromatic amino acid decarboxylase deficiency