Traits

Traits linked to POMT1

protein O-mannosyltransferase 1

The Human Phenotype Ontology links 196 traits to POMT1, by body system: features seen in people with one of the gene's rare conditions.

POMT1

Abnormality of the nervous system

Trait	How often it is seen
Absent speech development	Always
Agyria	Always
Cerebellar vermis hypoplasia	Always
Delayed ability to walk	Always
Epilepsy	Always
Global developmental delay	Always
Inability to walk	Always
Intellectual disability	Always
Intellectual disability, severe	Always
Small brainstem	Always
Small cerebellum	Always
Type II lissencephaly	Always
Abnormal cerebellar vermis morphology	Very often (80–99%)
Abnormal cortical gyration	Very often (80–99%)
Abnormal gait	Very often (80–99%)
Abnormal speech pattern	Very often (80–99%)
Abnormality of neuronal migration	Very often (80–99%)
Absent reflexes	Very often (80–99%)
Cognitive impairment	Very often (80–99%)
Decreased reflex response	Very often (80–99%)
EEG abnormality	Very often (80–99%)
Fewer and broader ridges in brain	Very often (80–99%)
Fewer or absent grooves in brain	Very often (80–99%)
More grooves in brain	Very often (80–99%)
Specific learning disability	Very often (80–99%)
Too much cerebrospinal fluid in the brain	Very often (80–99%)
Ventriculomegaly	Very often (80–99%)
Abnormal cerebral white matter morphology	Often (30–79%)
Abnormal pyramidal sign	Often (30–79%)
Abnormal shape of brain	Often (30–79%)
Abnormal shape of brainstem	Often (30–79%)
Abnormality of movement	Often (30–79%)
Abnormality of the cerebellum	Often (30–79%)
Absent septum pellucidum	Often (30–79%)
Agenesis of corpus callosum	Often (30–79%)
Decrease in size of the outer layer of the brain due to loss of brain cells	Often (30–79%)
Degeneration of cerebellum	Often (30–79%)
Delayed speech and language development	Often (30–79%)
Diffuse white matter abnormalities	Often (30–79%)
Dilated fourth ventricle	Often (30–79%)
Focal cortical dysplasia	Often (30–79%)
Gray matter heterotopia	Often (30–79%)
Kinked brainstem	Often (30–79%)
Motor delay	Often (30–79%)
Poor gross motor coordination	Often (30–79%)
Toe walking	Often (30–79%)
Waddling gait	Often (30–79%)
Abnormal periventricular white matter morphology	Sometimes (5–29%)
Abnormal pons morphology	Sometimes (5–29%)
Abnormality of the nervous system	Sometimes (5–29%)
Absent/small cerebellum	Sometimes (5–29%)
Autism spectrum disorder	Sometimes (5–29%)
Cerebellar cyst	Sometimes (5–29%)
Clonus	Sometimes (5–29%)
Decreased thalamic volume	Sometimes (5–29%)
Diminished deep tendon reflex	Sometimes (5–29%)
Fusion of the cerebellar hemispheres	Sometimes (5–29%)
Holoprosencephaly	Sometimes (5–29%)
Hypoplasia of the pons	Sometimes (5–29%)
Impaired visuospatial constructive cognition	Sometimes (5–29%)
Increased reflexes	Sometimes (5–29%)
Intellectual disability, mild	Sometimes (5–29%)
Loss of ability to walk	Sometimes (5–29%)
Meningocele	Sometimes (5–29%)
Olivopontocerebellar hypoplasia	Sometimes (5–29%)
Paralysis or weakness of one side of body	Sometimes (5–29%)
Poor speech	Sometimes (5–29%)
Underdevelopment of part of brain called corpus callosum	Sometimes (5–29%)
Cerebellar dysplasia	Not recorded
Excessive daytime sleepiness	Not recorded
IQ less than 20	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Difficulty walking up stairs	Always
Hypoglycosylation of alpha-dystroglycan	Always
Low muscle tone, in neonatal onset	Always
Muscular dystrophy	Always
Absent/small skeletal muscles	Very often (80–99%)
Decreased muscle tone in infant	Very often (80–99%)
EMG abnormality	Very often (80–99%)
Low muscle tone	Very often (80–99%)
Muscle degeneration	Very often (80–99%)
Muscle tissue disease	Very often (80–99%)
Muscle weakness	Very often (80–99%)
Reduced muscle fiber alpha dystroglycan	Very often (80–99%)
Centrally nucleated skeletal muscle fibers	Often (30–79%)
EMG: myopathic abnormalities	Often (30–79%)
Excessive inward curvature of lower spine	Often (30–79%)
Fatigable weakness of skeletal muscles	Often (30–79%)
Fatty replacement of skeletal muscle	Often (30–79%)
Frequent falls	Often (30–79%)
Generalized decreased muscle tone	Often (30–79%)
Generalized muscle weakness	Often (30–79%)
Gowers sign	Often (30–79%)
Increased skeletal muscle cells	Often (30–79%)
Increased variability in muscle fiber diameter	Often (30–79%)
Joint stiffness	Often (30–79%)
Multiple joint contractures	Often (30–79%)
Muscle spasm	Often (30–79%)
Proximal neurogenic muscle weakness	Often (30–79%)
Spasticity and rigidity of muscles	Often (30–79%)
Wasting of muscles near the body	Often (30–79%)
Abnormality of connective tissue	Sometimes (5–29%)
Axial muscle weakness	Sometimes (5–29%)
Diffuse skeletal muscle wasting	Sometimes (5–29%)
Kyphoscoliosis	Sometimes (5–29%)
Limited neck movement	Sometimes (5–29%)
Neuropathic spinal arthropathy	Sometimes (5–29%)
Reduced spine movement	Sometimes (5–29%)
Scoliosis	Sometimes (5–29%)
Tired easily	Sometimes (5–29%)
Type 1 muscle fiber predominance	Sometimes (5–29%)
Congenital contracture	Not recorded
Flexed joint that cannot be straightened	Not recorded
Severely decreased muscle tone	Not recorded

Abnormality of the eye

Trait	How often it is seen
Abnormally small eyeball	Always
Corneal opacity	Always
Retinal dysplasia	Always
Breakdown of light-sensitive cells in back of eye	Very often (80–99%)
Chorioretinal dysplasia	Very often (80–99%)
Close sighted	Very often (80–99%)
Cross-eyed	Very often (80–99%)
Glaucoma	Very often (80–99%)
Optic atrophy	Very often (80–99%)
Optic nerve issue	Very often (80–99%)
Retinal detachment	Very often (80–99%)
Visual impairment	Very often (80–99%)
Absence of eyeballs	Often (30–79%)
Clouding of the lens of the eye	Often (30–79%)
Abnormality of the eye	Sometimes (5–29%)
Abnormality of the iris	Sometimes (5–29%)
Cat eye	Sometimes (5–29%)
Clouding of the lens of the eye at birth	Sometimes (5–29%)
Cornea of eye less than 10mm in diameter	Sometimes (5–29%)
Enlarged cornea	Sometimes (5–29%)
Notched pupil	Sometimes (5–29%)
Optic nerve hypoplasia	Sometimes (5–29%)
Pigmentary retinopathy	Sometimes (5–29%)
Blindness	Rarely (1–4%)
Enlarged eyeball	Not recorded
Peters anomaly	Not recorded
Retinal atrophy	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Always
Dandy-Walker malformation	Always
Expressionless face	Always
Meningoencephalocele	Always
Abnormally large tongue	Often (30–79%)
Big calvaria	Often (30–79%)
Facial diplegia	Often (30–79%)
Little lower jaw	Often (30–79%)
Sloping forehead	Often (30–79%)
Abnormality of the tongue muscle	Sometimes (5–29%)
Bell's palsy	Sometimes (5–29%)
Bifid uvula	Sometimes (5–29%)
Brain tissue sticks out through back of skull	Sometimes (5–29%)
Cleft palate	Sometimes (5–29%)
Submucous cleft hard palate	Sometimes (5–29%)
Cleft upper lip	Not recorded
Enlarged cisterna magna	Not recorded
Posterior fossa cyst	Not recorded

Abnormality of limbs

Trait	How often it is seen
Limb-girdle muscle weakness	Always
Increased size of calf muscles	Very often (80–99%)
Metatarsus valgus	Very often (80–99%)
Calf muscle pseudohypertrophy	Often (30–79%)
Increased thigh size	Often (30–79%)
Shortening of the achilles tendon	Often (30–79%)
Wasting of limb-girdle muscle	Often (30–79%)
Hip dislocation	Sometimes (5–29%)
Triceps weakness	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Low-set ears	Often (30–79%)
Ears rotated toward back of head	Sometimes (5–29%)
Prominent ear	Sometimes (5–29%)
Absent ear canal	Not recorded
Small ears	Not recorded

Abnormality of the genitourinary system

Trait	How often it is seen
Undescended testes	Always
Underdeveloped penis	Often (30–79%)
Short penis	Sometimes (5–29%)
Renal dysplasia	Not recorded
Small male external genitalia	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Breathing difficulties	Sometimes (5–29%)
Breathing difficulty	Sometimes (5–29%)
Cough	Sometimes (5–29%)
Respiratory failure	Sometimes (5–29%)
Respiratory function loss	Sometimes (5–29%)

Laboratory abnormality

Trait	How often it is seen
Elevated blood creatine phosphokinase	Always
Abnormal circulating aldolase concentration	Very often (80–99%)
Abnormal circulating lactate dehydrogenase concentration	Very often (80–99%)
Abnormal levels of creatine kinase in blood	Very often (80–99%)
Mildly elevated creatine kinase	Often (30–79%)

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties in infancy	Always
Feeding difficulties	Often (30–79%)
Abdominal pain	Sometimes (5–29%)
Absent anus	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Disease of the heart muscle	Sometimes (5–29%)
Left ventricular hypertrophy	Sometimes (5–29%)
Abnormal left ventricular function	Not recorded

Abnormality of the voice

Trait	How often it is seen
Abnormality of the voice	Often (30–79%)

Constitutional symptom

Trait	How often it is seen
Muscle ache	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 POMT1 and how often each is seen. Find out more at hpo.jax.org.

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