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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

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

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AE-AADC-0267 | August 2022

Welcome to "About AADC MEA"

This website is provided for healthcare professionals residing in the Middle East and Africa.

This educational website provides information to support the early and accurate diagnosis of rare neurotransmitter disorders, including Aromatic L-amino Acid Decarboxylase (AADC) deficiency.