Dark Colored Urine in a 2-Year-Old Child

[摘要] A 2-year-old male was referred to the metabolism service after his mother noticed dark-colored staining on his crib sheets on several occasions. She also noted that the child's urine was normal when he urinated but turned a dark color over a short period of time (Fig. 1A). His past medical history, development and physical exam were unremarkable. The family history however was notable for several maternal relatives with dark-colored urine. His parents were nonconsanguineous. A urine specimen was collected for organic acids analysis by GC-MS. The results are shown in Fig. 1B.Fig. 1. (A), Patient's urine sample; (B), Organic acids analysis of patient urine using GC-MS.Urine organic acids were extracted into ethyl acetate/ether and converted to trimethylsilyl derivatives prior to analysis using a GC 6890N/MS 5975 system equipped with a DB-1 column (Agilent). PDA, pentadecanoate; IS, internal standard.This patient has alkaptonuria, a rare disorder (approximately 1 in 250 000) caused by a deficiency of the enzyme homogentisate 1,2-dioxygenase (HGD3; EC.1.13.11.5). Under normal conditions, …

[学科分类] 过敏症与临床免疫学