Traits

Traits linked to LETM1

leucine zipper and EF-hand containing transmembrane protein 1

The Human Phenotype Ontology links 166 traits to LETM1, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of head or neck

Trait	How often it is seen
Abnormal lip	Very often (80–99%)
Abnormality of the mouth	Very often (80–99%)
Abnormality of the philtrum	Very often (80–99%)
Abnormally small head	Very often (80–99%)
Downturned corners of mouth	Very often (80–99%)
Downward slanting of the opening between the eyelids	Very often (80–99%)
Eye folds	Very often (80–99%)
Failure of development of between one and six teeth	Very often (80–99%)
Frontal bossing	Very often (80–99%)
High forehead	Very often (80–99%)
High frontal hairline	Very often (80–99%)
Highly arched eyebrow	Very often (80–99%)
Little lower jaw	Very often (80–99%)
Long, narrow head	Very often (80–99%)
Low hairline at back of neck	Very often (80–99%)
Short philtrum	Very often (80–99%)
Wide nasal bridge	Very often (80–99%)
Abnormality of craniofacial shape	Often (30–79%)
Beaked nose	Often (30–79%)
Cleft of the mouth	Often (30–79%)
Cleft upper lip	Often (30–79%)
Cranial defect	Often (30–79%)
Delayed eruption of teeth	Often (30–79%)
Pit in front of the ear	Often (30–79%)
Prominent area between the eyebrows	Often (30–79%)
Short upper lip	Often (30–79%)
Skin tag in front of the ear	Often (30–79%)
Taurodontia	Often (30–79%)
Cleft palate	Sometimes (5–29%)
High palate	Sometimes (5–29%)
Long face	Sometimes (5–29%)
Narrow forehead	Sometimes (5–29%)
Webbed neck	Sometimes (5–29%)

Abnormality of the nervous system

Trait	How often it is seen
Ataxia	Very often (80–99%)
EEG abnormality	Very often (80–99%)
Epilepsy	Very often (80–99%)
Global developmental delay	Very often (80–99%)
Intellectual disability	Very often (80–99%)
Intellectual disability, severe	Very often (80–99%)
Babinski sign	Often (30–79%)
Brisk reflexes	Often (30–79%)
Cerebellar vermis hypoplasia	Often (30–79%)
Difficulty sleeping	Often (30–79%)
Hyperactive movements	Often (30–79%)
Inability to coordinate movements when walking	Often (30–79%)
Loss of ability to walk	Often (30–79%)
Loss of developmental milestones	Often (30–79%)
Morphological central nervous system abnormality	Often (30–79%)
Peripheral neuropathy	Often (30–79%)
Repetitive movements	Often (30–79%)
Tethered cord	Often (30–79%)
Abnormality of movement	Sometimes (5–29%)
Absent/small cerebellum	Sometimes (5–29%)
Agenesis of corpus callosum	Sometimes (5–29%)
Degeneration of cerebellum	Sometimes (5–29%)
Too much cerebrospinal fluid in the brain	Sometimes (5–29%)
Absent septum pellucidum	Not recorded
Cavum septum pellucidum	Not recorded
Periventricular cysts	Not recorded
Ventriculomegaly	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Decreased muscle mass	Very often (80–99%)
Generalized decreased muscle tone	Very often (80–99%)
Low muscle tone	Very often (80–99%)
Abnormal vertebral body morphology	Often (30–79%)
Abnormal vertebral morphology	Often (30–79%)
Abnormality of the chest	Often (30–79%)
Abnormality of the vertebral column	Often (30–79%)
Congenital diaphragmatic hernia	Often (30–79%)
Delayed bone maturation	Often (30–79%)
Hunched back	Often (30–79%)
Hypoplastic pubic ramus	Often (30–79%)
Involuntary muscle stiffness, contraction, or spasm	Often (30–79%)
Muscle degeneration	Often (30–79%)
Rib fusion	Often (30–79%)
Rib segmentation abnormalities	Often (30–79%)
Scoliosis	Often (30–79%)
Abnormal formation of the hip	Sometimes (5–29%)
Hernia	Sometimes (5–29%)
Osteoporosis	Sometimes (5–29%)
Abnormal maturation of breastbone	Not recorded
Vertebral fusion	Not recorded

Abnormality of the eye

Trait	How often it is seen
Visual impairment	Always
Optic atrophy	Very often (80–99%)
Wide-set eyes	Very often (80–99%)
Bulging eye	Often (30–79%)
Cat eye	Often (30–79%)
Clouding of the lens of the eye	Often (30–79%)
Cross-eyed	Often (30–79%)
Drooping upper eyelid	Often (30–79%)
Involuntary, rapid, rhythmic eye movements	Often (30–79%)
Opto-chiasmatic atrophy	Often (30–79%)
Rieger anomaly	Often (30–79%)
Enlarged cornea	Sometimes (5–29%)
Glaucoma	Sometimes (5–29%)
Hardening of skin and connective tissue	Sometimes (5–29%)
Noninflammatory retina disease	Sometimes (5–29%)
Displaced pupil	Not recorded

Abnormality of limbs

Trait	How often it is seen
Abnormal feet structure	Often (30–79%)
Club feet	Often (30–79%)
Extra thumb	Often (30–79%)
Long slender fingers	Often (30–79%)
Short big toe	Often (30–79%)
Short thumb	Often (30–79%)
Split hand	Often (30–79%)
Preaxial foot polydactyly	Sometimes (5–29%)
Single transverse palmar crease	Sometimes (5–29%)
Front half of foot turns inward	Not recorded
Fused forearm bones	Not recorded
Hip dislocation	Not recorded
Metacarpal pseudoepiphysis	Not recorded

Abnormality of the ear

Trait	How often it is seen
Ears rotated toward back of head	Very often (80–99%)
Small ears	Very often (80–99%)
Abnormally shaped ears	Often (30–79%)
Bilateral sensorineural hearing impairment	Often (30–79%)
Conductive deafness	Often (30–79%)
Hearing impairment	Often (30–79%)
Narrow ear canal	Often (30–79%)
Chronic infections of the middle ear	Sometimes (5–29%)
Low-set ears	Sometimes (5–29%)
Sensorineural hearing impairment	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Abnormal cardiac septum morphology	Often (30–79%)
Abnormal cardiovascular system morphology	Often (30–79%)
Abnormal heart valve morphology	Often (30–79%)
An opening in the wall separating the top two chambers of the heart	Often (30–79%)
Disease of the heart muscle	Often (30–79%)
Strawberry mark	Often (30–79%)
Fluid around heart	Sometimes (5–29%)
Accessory spleen	Not recorded
Hole in heart wall separating two lower heart chambers	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Hypospadias	Very often (80–99%)
Abnormality of the kidney	Often (30–79%)
Undescended testes	Often (30–79%)
Abnormality of the genitourinary system	Sometimes (5–29%)
Abnormality of the reproductive system	Sometimes (5–29%)
Absent uterus	Sometimes (5–29%)
Streak ovary	Sometimes (5–29%)
Urinary tract abnormalities	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Faltering weight	Very often (80–99%)
Growth delay	Very often (80–99%)
Prenatal growth deficiency	Very often (80–99%)
Small for gestational age	Very often (80–99%)
Severe growth delay in children	Often (30–79%)
Short stature	Often (30–79%)
Disproportionate tall stature	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties	Often (30–79%)
Abdominal situs inversus	Sometimes (5–29%)
Abnormality of the gallbladder	Sometimes (5–29%)
Biliary tract abnormality	Sometimes (5–29%)
Acid reflux	Not recorded
Malrotation of small bowel	Not recorded

Abnormality of the integument

Trait	How often it is seen
Dry skin	Often (30–79%)
Focal absence of scalp tissue	Often (30–79%)
Spinal dimple	Often (30–79%)
Hyperconvex fingernails	Not recorded

Laboratory abnormality

Trait	How often it is seen
3-Methylglutaconic aciduria	Often (30–79%)
Higher than normal levels of lactate in blood	Often (30–79%)
Alpha-aminoadipic aciduria	Sometimes (5–29%)
Elevated urine acetoacetic acid level	Sometimes (5–29%)

Abnormality of the immune system

Trait	How often it is seen
Decreased immune function	Often (30–79%)
Abnormality of the immune system	Sometimes (5–29%)
Recurrent respiratory infections	Sometimes (5–29%)

Abnormal cellular phenotype

Trait	How often it is seen
Decreased circulating IgA concentration	Often (30–79%)

Abnormality of prenatal development or birth

Trait	How often it is seen
Less than 10 fetal movements in 12 hours	Very often (80–99%)

Abnormality of the breast

Trait	How often it is seen
Absent/small nipples	Sometimes (5–29%)

Abnormality of the endocrine system

Trait	How often it is seen
Early onset of puberty	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Absent/small lungs	Often (30–79%)

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.

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the traits linked to LETM1 and how often each is seen. Find out more at hpo.jax.org.

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