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Trait

Onion bulb formation

Repeated episodes of segmental demyelination and remyelination lead to the accumulation of supernumerary Schwann cells around axons, which is referred to as onion bulb formation. This finding affects peripheral nerves.

HPO HP:0003383

Summary

Body system
Abnormality of the nervous system

30 genes linked to Onion bulb formation

Changes in these genes cause rare conditions in which Onion bulb formation 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.

GeneHow often it is seenConditions
AFG3L2AFG3 like matrix AAA peptidase subunit 2AlwaysIn 1 condition
EGR2early growth response 2AlwaysIn 2 conditions
FGD4FYVE, RhoGEF and PH domain containing 4AlwaysIn 1 condition
GDAP1ganglioside induced differentiation associated protein 1AlwaysIn 3 conditions
GJB1gap junction protein beta 1AlwaysIn 1 condition
GNB4G protein subunit beta 4AlwaysIn 1 condition
HYCC1hyccin PI4KA lipid kinase complex subunit 1AlwaysIn 1 condition
INF2inverted formin 2AlwaysIn 1 condition
MPZmyelin protein zeroAlwaysIn 4 conditions
NEFLneurofilament light chainAlwaysIn 2 conditions
PMP2peripheral myelin protein 2AlwaysIn 1 condition
PMP22peripheral myelin protein 22AlwaysIn 4 conditions
PRXperiaxinAlwaysIn 2 conditions
SBF1SET binding factor 1AlwaysIn 1 condition
MTRFRmitochondrial translation release factor in rescueOften (30–79%)In 2 conditions
ARHGEF10Rho guanine nucleotide exchange factor 10Not recordedIn 1 condition
COX6A1cytochrome c oxidase subunit 6A1Not recordedIn 1 condition
DCAF8DDB1 and CUL4 associated factor 8Not recordedIn 1 condition
DNM2dynamin 2Not recordedIn 1 condition
FIG4FIG4 phosphoinositide 5-phosphataseNot recordedIn 1 condition
GBF1golgi brefeldin A resistant guanine nucleotide exchange factor 1Not recordedIn 1 condition
KIF1Bkinesin family member 1BNot recordedIn 1 condition
LITAFlipopolysaccharide induced TNF factorNot recordedIn 1 condition
LMNAlamin A/CNot recordedIn 1 condition
MFN2mitofusin 2Not recordedIn 1 condition
NDRG1N-myc downstream regulated 1Not recordedIn 1 condition
PRPS1phosphoribosyl pyrophosphate synthetase 1Not recordedIn 1 condition
SACSsacsin molecular chaperoneNot recordedIn 1 condition
SBF2SET binding factor 2Not recordedIn 1 condition
SLC12A6solute carrier family 12 member 6Not recordedIn 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.

Narrower traits

Broader traits

Abnormal peripheral myelination

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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