Rare diseases · Sign or symptom

Abnormal pineal melatonin secretion

HP:0012689

What it means

An anomaly in the amount or timing of melatonin secretion by the pineal gland. Note that melatonin is also synthesized by multiple tissues outside of the pineal gland.

The rhythm of melatonin synthesized in and released from the pineal gland is characterized by a prominent nocturnal peak, which also contains temporal information that had originated in the suprachiasmatic nucleus. Strong reductions of circulating melatonin are also observed in numerous disorders and diseases, including Alzheimer's disease, various other neurological and stressful conditions, pain, cardiovascular diseases, cases of cancer, endocrine and metabolic disorders, in particular diabetes type 2.

Rare diseases that can present with this4

The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.

Part of the broader category

Abnormal pineal melatonin secretion

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This page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.