Rare diseases · Sign or symptom
Necklace skeletal muscle fibers
HP:0031238
What it means
A histological alteration of muscle fibers that resembles a necklace (necklace fibers). A substantial proportion of fibers (4-20% in PMID:19084976) show internalized nuclei aligned in a basophilic ring (necklace) at 3 micrometers beneath the sarcolemma. Ultrastructurally, such necklaces consist of myofibrils of smaller diameter, in oblique orientation, surrounded by mitochondria, sarcoplasmic reticulum and glycogen granules.
Rare diseases that can present with this1
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: Necklace skeletal muscle fibres
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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.