PPM - Analysis of Acylcarnitines-Description and References

Description and References

Pdf Summary

The document titled "Analysis of Acylcarnitines" is designed for clinical biochemical geneticists involved in analyzing, interpreting, and reporting acylcarnitine profiles. The primary learning objective is to align analysis practices with the current American College of Medical Genetics and Genomics (ACMG) guidelines.<br /><br />Acylcarnitines consist of a carnitine backbone linked to variable acyl-chains. This profile is essential for diagnosing and monitoring mitochondrial fatty acid oxidation disorders (FAOD) and some organic acidemias. It is performed using plasma or dried blood spots, with the latter being crucial for newborn screenings. Less frequently, samples for acylcarnitine profile analysis could come from urine, amniotic fluid, bile, or cultured fibroblasts.<br /><br />The primary method for analyzing these profiles is flow-injection mass spectrometry (FIA-MS/MS), which uses derivatization and isotope-labeled internal standards to enable quantification. Diagnosis hinges on identifying abnormal patterns, often involving multiple acylcarnitine species, and determining specific acylcarnitine ratios. The profiles can be affected by medications, dietary intake, fasting, carnitine levels, and liver or kidney function. Since some acylcarnitines are isobaric and cannot be differentiated with FIA-MS/MS, some laboratories use LC-MS/MS reflex testing to separate these compounds.<br /><br />Comprehensive interpretation of acylcarnitine profiles usually involves additional tests such as organic acid, acylglycine, amino acid, and carnitine analyses, alongside clinical evaluations. The document also references essential literature by the ACMG and specialists in inherited disorder management, providing further detailed guidance on the technical standards and clinical application of acylcarnitine analysis.

Keywords

acylcarnitines

clinical biochemical genetics

ACMG guidelines

mitochondrial fatty acid oxidation disorders

flow-injection mass spectrometry

newborn screening

isotope-labeled standards

LC-MS/MS reflex testing

organic acidemias

acylcarnitine profiles