Trait
Black feces
Clinical name: Melena
The passage of blackish, tarry feces associated with gastrointestinal hemorrhage. Melena occurs if the blood remains in the colon long enough for it to be broken down by colonic bacteria. One degradation product, hematin, imbues the stool with a blackish color. Thus, melena generally occurs with bleeding from the upper gastrointestinal tract (e.g., stomach ulcers or duodenal ulcers), since the blood usually remains in the gut for a longer period of time than with lower gastrointestinal bleeding.
Reference genomeGRCh38hg38
Positions on gene and variant pages follow this choice, in this browser.
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Get my Genome Test23 genes linked to Black feces
Changes in these genes cause rare conditions in which Black feces is seen. Most people with this trait have none of those conditions, and a gene on this list says nothing about anyone's own genome.
| Gene | How often it is seen | Conditions |
|---|---|---|
| SPOUT1SPOUT domain containing methyltransferase 1 | Always | In 1 condition |
| ACVRL1activin A receptor like type 1 | Often (30–79%) | In 1 condition |
| BMPR1Abone morphogenetic protein receptor type 1A | Often (30–79%) | In 1 condition |
| PTENphosphatase and tensin homolog | Often (30–79%) | In 1 condition |
| APCAPC regulator of Wnt signaling pathway | Sometimes (5–29%) | In 1 condition |
| ATRXATRX chromatin remodeler | Sometimes (5–29%) | In 1 condition |
| CD109CD109 molecule | Sometimes (5–29%) | In 1 condition |
| CDKN1Bcyclin dependent kinase inhibitor 1B | Sometimes (5–29%) | In 1 condition |
| CDKN2Bcyclin dependent kinase inhibitor 2B | Sometimes (5–29%) | In 1 condition |
| F8coagulation factor VIII | Sometimes (5–29%) | In 1 condition |
| F9coagulation factor IX | Sometimes (5–29%) | In 1 condition |
| FAHfumarylacetoacetate hydrolase | Sometimes (5–29%) | In 1 condition |
| GP1BAglycoprotein Ib platelet subunit alpha | Sometimes (5–29%) | In 1 condition |
| GP1BBglycoprotein Ib platelet subunit beta | Sometimes (5–29%) | In 1 condition |
| ITGA2integrin subunit alpha 2 | Sometimes (5–29%) | In 1 condition |
| ITGA2Bintegrin subunit alpha 2b | Sometimes (5–29%) | In 1 condition |
| ITGB3integrin subunit beta 3 | Sometimes (5–29%) | In 1 condition |
| KIF23kinesin family member 23 | Sometimes (5–29%) | In 1 condition |
| MEN1menin 1 | Sometimes (5–29%) | In 1 condition |
| RACGAP1Rac GTPase activating protein 1 | Sometimes (5–29%) | In 1 condition |
| SREBF1sterol regulatory element binding transcription factor 1 | Sometimes (5–29%) | In 1 condition |
| ENGendoglin | Not recorded | In 1 condition |
| WASWASP actin nucleation promoting factor | Not recorded | In 1 condition |
How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.
Broader traits
Where this comes from
- The Human Phenotype Ontology, release 2026-09-01: the trait, its names, its definition and the genes linked to it. Find out more at hpo.jax.org.
- Data release 2026.10.16-c6eea6bf.
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