Rare diseases · Sign or symptom
Decreased circulating T4 concentration
HP:0031507
What it means
A reduction below the normal concentration of thyroxine in the blood. Thyroxine (also known as T4) is the main hormone secreted by the thyroid gland into the blood. It can be converted into the active form triiodothyronine (also known as T3).
Rare diseases that can present with this15
Very common80–99%
4Common30–79%
8- Congenital hypothyroidism due to transplacental passage of TSH-binding inhibitory antibodies
- Genetic transient congenital hypothyroidism
- Hypothyroidism due to deficient transcription factors involved in pituitary development or function
- Hypothyroidism due to TSH receptor mutations
- Prader-Willi syndrome due to paternal 15q11q13 deletion
- Prader-Willi syndrome due to paternal deletion of 15q11q13 type 1
- Prader-Willi syndrome due to paternal deletion of 15q11q13 type 2
- Resistance to thyrotropin-releasing hormone syndrome
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
Also called: Decreased circulating T4 level · Decreased circulating thyroxine level · Reduced T4 plasma level
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Start free with EleplanThis 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.