{{Rsnum
|rsid=6592961
|Gene=DDC
|Chromosome=7
|position=50505192
|Orientation=plus
|GMAF=0.264
|Assembly=GRCh38
|GenomeBuild=38.1
|dbSNPBuild=141
|geno1=(A;A)
|geno2=(A;G)
|geno3=(G;G)
|Gene_s=DDC
}}{{ population diversity
| geno1=(A;A)
| geno2=(A;G)
| geno3=(G;G)
| CEU | 7.1 | 39.8 | 53.1
| HCB | 2.9 | 32.1 | 65.0
| JPT | 3.5 | 31.9 | 64.6
| YRI | 25.2 | 43.5 | 31.3
| ASW | 12.3 | 38.6 | 49.1
| CHB | 2.9 | 32.1 | 65.0
| CHD | 4.6 | 23.9 | 71.6
| GIH | 6.9 | 34.7 | 58.4
| LWK | 15.5 | 43.6 | 40.9
| MEX | 12.1 | 46.6 | 41.4
| MKK | 9.0 | 39.7 | 51.3
| TSI | 1.0 | 32.4 | 66.7
| HapMapRevision=28
}}Exploration of 19 serotoninergic candidate genes in adults and children with [[attention-deficit/hyperactivity disorder]] identifies association for [[5HT2A]], [[DDC]] and [[MAOB]]. {{PMID|17938636}} A allele associated with [[ADHD]] in adults and children.

{{PMID Auto
|PMID=22397633
|Title=Neurotransmitter systems and neurotrophic factors in autism: association study of 37 genes suggests involvement of DDC.
}}

{{on chip | 23andMe v1}}
{{on chip | 23andMe v2}}
{{on chip | 23andMe v3}}
{{on chip | 23andMe v4}}
{{on chip | FTDNA2}}
{{on chip | HumanOmni1Quad}}
{{on chip | Illumina Human 1M}}