A GC/MS-based metabolomic approach for diagnosing citrin deficiency

Area of Science:

• Biochemistry
• Genetics
• Metabolomics

Background:

• Citrin deficiency, caused by SLC25A13 gene mutations, leads to hyperammonemia with unique treatment needs.
• Current diagnostic methods for citrin deficiency can be slow and lack accuracy.
• Distinguishing citrin deficiency from other hyperammonemias is crucial for appropriate management.

Purpose of the Study:

• To develop a more rapid and accurate chemical diagnostic method for citrin deficiency.
• To identify novel urinary biomarkers for citrin deficiency using gas chromatography/mass spectrometry-based metabolomics.
• To differentiate citrin deficiency from other hyperammonemic disorders.

Main Methods:

• Reinvestigation of urine metabolome in patients with previously diagnosed citrin deficiency using gas chromatography/mass spectrometry.
• Analysis of specific metabolites including tyrosine, galactose, and glucose metabolites in younger patients.
• Evaluation of α-Ketoglutaramate (KGM) and other urea cycle-related biomarkers.

Main Results:

• Prominent urinary biomarkers in infants (2-5 months) with citrin deficiency included tyrosine, p-hydroxyphenyllactate, galactose metabolites, and cystathionine.
• These biomarkers were less pronounced in older patients and absent in other hyperammonemias.
• Increased α-Ketoglutaramate (KGM) was observed in most citrin deficiency patients, despite normal glutamine levels, aiding differential diagnosis.

Conclusions:

• Noninvasive urine metabolomics offers a more reliable and rapid chemical diagnosis for citrin deficiency.
• Analysis of specific metabolite profiles effectively differentiates citrin deficiency from other hyperammonemic syndromes.
• This approach enhances diagnostic capabilities for citrin deficiency, improving patient care.