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URL of this page: https://medlineplus.gov/genetics/gene/ddc/

DDC gene

dopa decarboxylase

Normal Function

The DDC gene provides instructions for making the aromatic l-amino acid decarboxylase (AADC) enzyme, which plays an important role in the brain and nervous system. This enzyme is involved in the final step of the chemical pathways that produce dopamine and serotonin, which are two types of neurotransmitters. Neurotransmitters are chemical messengers that transmit signals between nerve cells (neurons) and other cells in the body. Dopamine is involved in the creation of two additional neurotransmitters called norepinephrine and epinephrine.

The AADC enzyme plays a role in the two-step process that is used to create dopamine. First, the protein building block (amino acid) tyrosine is converted into a molecule called L-dopa. The AADC enzyme then removes a molecular structure called a carboxyl group (which consists of a carbon atom, two oxygen atoms, and a hydrogen atom) from L-dopa, creating dopamine. A similar process is used to make serotonin. The amino acid tryptophan is converted to 5-hydroxytryptophan before the AADC enzyme removes a carboxyl group, producing serotonin. 

Health Conditions Related to Genetic Changes

Aromatic l-amino acid decarboxylase deficiency

Variants (also called mutations) in the DDC gene cause AADC deficiency. AADC deficiency is an inherited disorder that affects the way neurons transmit information to other cells, and it can cause neurological problems early in life. Variants in the DDC gene reduce the activity of the AADC enzyme. This causes neurons to produce less dopamine and serotonin than normal, which in turn reduces the production of epinephrine and norepinephrine. Changes in the levels of these four neurotransmitters contribute to the developmental delays, intellectual disabilities, and abnormal movements seen in people with AADC deficiency.

More About This Health Condition

Other Names for This Gene

  • AADC
  • aromatic L-amino acid decarboxylase
  • dopa decarboxylase

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases

References

  • Bertoldi M. Mammalian Dopa decarboxylase: structure, catalytic activity and inhibition. Arch Biochem Biophys. 2014 Mar 15;546:1-7. doi: 10.1016/j.abb.2013.12.020. Epub 2014 Jan 6. Citation on PubMed
  • Blau N, Pearson TS, Kurian MA, Elsea SH. Aromatic L-Amino Acid Decarboxylase Deficiency. 2023 Oct 12. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2024. Available from http://www.ncbi.nlm.nih.gov/books/NBK595821/ Citation on PubMed
  • Brun L, Ngu LH, Keng WT, Ch'ng GS, Choy YS, Hwu WL, Lee WT, Willemsen MA, Verbeek MM, Wassenberg T, Regal L, Orcesi S, Tonduti D, Accorsi P, Testard H, Abdenur JE, Tay S, Allen GF, Heales S, Kern I, Kato M, Burlina A, Manegold C, Hoffmann GF, Blau N. Clinical and biochemical features of aromatic L-amino acid decarboxylase deficiency. Neurology. 2010 Jul 6;75(1):64-71. doi: 10.1212/WNL.0b013e3181e620ae. Epub 2010 May 26. Erratum In: Neurology. 2010 Aug 10;75(6):576. Dosage error in article text. Citation on PubMed
  • Hyland K. Inherited disorders affecting dopamine and serotonin: critical neurotransmitters derived from aromatic amino acids. J Nutr. 2007 Jun;137(6 Suppl 1):1568S-1572S; discussion 1573S-1575S. doi: 10.1093/jn/137.6.1568S. Citation on PubMed
  • Pearl PL, Capp PK, Novotny EJ, Gibson KM. Inherited disorders of neurotransmitters in children and adults. Clin Biochem. 2005 Dec;38(12):1051-8. doi: 10.1016/j.clinbiochem.2005.09.012. Epub 2005 Nov 18. Citation on PubMed
  • Pearl PL, Taylor JL, Trzcinski S, Sokohl A. The pediatric neurotransmitter disorders. J Child Neurol. 2007 May;22(5):606-16. doi: 10.1177/0883073807302619. Citation on PubMed
  • Verbeek MM, Geurtz PB, Willemsen MA, Wevers RA. Aromatic L-amino acid decarboxylase enzyme activity in deficient patients and heterozygotes. Mol Genet Metab. 2007 Apr;90(4):363-9. doi: 10.1016/j.ymgme.2006.12.001. Epub 2007 Jan 19. Citation on PubMed
  • Yu Y, Panhuysen C, Kranzler HR, Hesselbrock V, Rounsaville B, Weiss R, Brady K, Farrer LA, Gelernter J. Intronic variants in the dopa decarboxylase (DDC) gene are associated with smoking behavior in European-Americans and African-Americans. Hum Mol Genet. 2006 Jul 15;15(14):2192-9. doi: 10.1093/hmg/ddl144. Epub 2006 Jun 1. Citation on PubMed
  • Zhang H, Ye Y, Wang X, Gelernter J, Ma JZ, Li MD. DOPA decarboxylase gene is associated with nicotine dependence. Pharmacogenomics. 2006 Dec;7(8):1159-66. doi: 10.2217/14622416.7.8.1159. Citation on PubMed

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