Potential Misdiagnosis of 3-Methylcrotonyl-Coenzyme A Carboxylase Deficiency Associated With Absent or Trace Urinary 3-Methylcrotonylglycine

Abstract

We report 2 patients with isolated 3-methylcrotonyl-coenzyme A carboxylase deficiency whose urine was devoid of, or contained only trace, 3-methylcrotonylglycine, the pathognomonic marker for this disorder. The first patient, a girl with trisomy 21, was detected through newborn screening with an elevated 5 carbon hydroxycarnitine species level, and the second patient came to clinical attention at the age of 5 months because of failure to thrive and developmental delay. Investigation of urinary organic acids revealed an elevated 3-hydr Show more