3-OMD testing for AADC deficiency
  • Free 3-OMD dry spot testing and reflex DDC gene sequencing is offered by PTC Therapeutics to help your diagnosis of patients with suspected AADC deficiency

What is AADC deficiency?1

What is 3-OMD?2

  • Aromatic-L-amino acid decarboxylase (AADC) deficiency is an inborn error of neurotransmitter biosynthesis
  • It is an autosomal recessive disorder caused by pathogenic variants in the dopa decarboxylase gene, DDC, encoding for the AADC enzyme
  • 3-O-methyldopa (3-OMD) is a more stable, catabolic product of L-DOPA
  • Accumulation of L-DOPA leads to increased concentrations of 3-OMD through conversion by catechol-O-methyltransferase
  • 3-OMD is detectable and stable in blood
Why is 3-OMD elevated in patients with AADC deficiency?1,2
  • In patients with AADC deficiency, lack of AADC enzyme leads to accumulation of its substrate L-DOPA
  • L-DOPA is methylated to the more stable form, 3-OMD
How does 3-OMD screening help in the diagnosis of AADC deficiency?1-5
Elevated levels of 3-OMD can be detected in blood
Clinical suspicion of AADC deficiency
Screen for
 3-OMD levels in blood
Confirm with diagnostic tests
  • DDC full gene sequencing
  • Plasma AADC enzyme activity
  • CSF neurotransmitter metabolites
To diagnose AADC deficiency, genetic testing should be performed and 2 of the 3 core diagnostic tests should be positive
  • 3-OMD can be used as an initial screen when AADC deficiency is suspected
  • Elevated levels of 3-OMD in the blood should prompt further testing to confirm the diagnosis of AADC deficiency
The 3-OMD dried blood spot assay is validated for testing in AADC deficiency6
  • 3-OMD is increased in DBS of patients with AADC deficiency hence it is a valid and reliable biomarker for detection of AADC deficiency3
  • In studies e valuating testing for AADC deficiency, dried blood spot testing for 3-OMD was found to have a high positive-predictive rate in newborn screening2,3,5,a
  • CENTOGENE has performed their own validation studies in 3-OMD testing, showing 100% sensitivity and specificity of the assay in patients with AADC deficiency vs normal controls6
CENTOGENE study: 3-OMD concentration in dried blood spot (DBS) from controls and patients with AADC deficiency
Elevated 3-OMD levels in the blood can be detected relatively easily with a simple and rapid test2,3
  • Dried blood spot testing for 3-OMD levels is a simple, rapid, minimally invasive test used for AADC deficiency2,3
  • Hence , it is an option for screening individuals at high risk for AADC deficiency and a potential option for newborn screening2,5
  • This test may aid early diagnosis of AADC deficiency and help to bridge the delay (typically months to years) in the diagnosis of the disease1,5
Screening for elevated 3-OMD in the blood of patients with suspected AADC deficiency may aid in early diagnosis5
Partnership with CENTOGENE
  • PTC has partnered with CENTOGENE to offer 3-OMD testing via dried blood spot for initial screening of patients in whom AADC deficiency is clinically suspected and/or in at-risk patient populations4
  • For additional information, contact
    [email protected]

aIn one study, one newborn had a false positive; investigations showed the mother was on l-DOPA therapy during pregnancy.3

Abbreviations: GC-MS, gas chromatography mass spectrometry; l-DOPA, L 3,4 dihydroxyphenylalanine; CSF, cerebrospinal fluid; DBS, dried blood spot; 3-OMD, 3-O-methyldopa; 5-HIAA, 5-hydroxyindoleacetic acid; 5-HTP, 5-hydroxytryptophan; HVA, homovanillic acid; VLA, vanillactic acid.

References: 1. Wassenberg T, et al. Orphanet J Rare Dis. 2017;12(1):12. doi:10.1186/s13023-016-0522-z. 2. Chen PW, et al. Clin Chim Acta. 2014;431:19-22. 3. Brennenstuhl H, et al. J Inherit Metab Dis. 2019;doi:10.1002/jimd.12208. 4. Hyland K, Reott M. Pediatr Neurol. 2020;106:38-42 5. Chien YH, et al. Mol Genet Metab. 2016;118(4):259-263. 6. Data on file. CENTOGENE AG. 2019

[maxbutton id="5"]

AE-AADC-0267 | August 2022