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Trait

Flattened and twisted hair

Clinical name: Pili torti

Pili (from Latin pilus, hair) torti (from Latin tortus, twisted) refers to short and brittle hairs that appear flattened and twisted when viewed through a microscope.

HPO HP:0003777

Summary

Body system
Abnormality of the integument

18 genes linked to Flattened and twisted hair

Changes in these genes cause rare conditions in which Flattened and twisted hair 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
ATP7AATPase copper transporting alphaAlwaysIn 1 condition
BCS1LBCS1 ubiquinol-cytochrome c reductase complex chaperoneAlwaysIn 2 conditions
CDH3cadherin 3AlwaysIn 2 conditions
ERCC2ERCC excision repair 2, TFIIH core complex helicase subunitAlwaysIn 1 condition
HEPHL1hephaestin like 1AlwaysIn 1 condition
NECTIN1nectin cell adhesion molecule 1AlwaysIn 2 conditions
NECTIN4nectin cell adhesion molecule 4AlwaysIn 1 condition
SPINK5serine peptidase inhibitor Kazal type 5AlwaysIn 2 conditions
ST14ST14 transmembrane serine protease matriptaseAlwaysIn 1 condition
TP63tumor protein p63AlwaysIn 1 condition
LMNAlamin A/CVery often (80–99%)In 1 condition
PEX1peroxisomal biogenesis factor 1Very often (80–99%)In 1 condition
PEX6peroxisomal biogenesis factor 6Very often (80–99%)In 1 condition
WRNWRN RecQ like helicaseVery often (80–99%)In 1 condition
ASLargininosuccinate lyaseSometimes (5–29%)In 1 condition
DSG4desmoglein 4Sometimes (5–29%)In 1 condition
PORCNporcupine O-acyltransferaseSometimes (5–29%)In 1 condition
KRT85keratin 85Not 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.

Broader traits

Abnormal hairshaft morphology

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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