Rare diseases · Sign or symptom
Facial hypotonia
Decreased facial muscle tone
HP:0000297
What it means
Reduced muscle tone of a muscle that is innervated by the facial nerve (the seventh cranial nerve).
Rare diseases that can present with this20
Common30–79%
6Sometimes5–29%
11- 20q13.33microdeletion syndrome
- Alacrimia-choreoathetosis-liver dysfunction syndrome
- Alpha-mannosidosis, infantile form
- Alternating hemiplegia of childhood
- Distal myotilinopathy
- Gabriele-de Vries syndrome
- Glycogen storage disease due to acid maltase deficiency
- Megalencephaly-severe kyphoscoliosis-overgrowth syndrome
and 3 more in this range
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: Atony of facial musculature · Hypotonic facies · Low facial muscle tone · Reduced facial muscle tone
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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.