Traits

Traits linked to FKTN

fukutin

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

FKTN

Abnormality of the nervous system

Trait	How often it is seen
Abnormal cerebral white matter morphology	Always
Absent speech development	Always
Agyria	Always
Epilepsy	Always
Global developmental delay	Always
Motor delay	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%)
Delayed speech and language development	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%)
Intellectual disability	Very often (80–99%)
Intellectual disability, severe	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%)
Abnormality of movement	Often (30–79%)
Absent septum pellucidum	Often (30–79%)
Agenesis of corpus callosum	Often (30–79%)
Degeneration of cerebellum	Often (30–79%)
Kinked brainstem	Often (30–79%)
Toe walking	Often (30–79%)
Absent/small cerebellum	Sometimes (5–29%)
Aplasia/Hypoplasia of the corpus callosum	Sometimes (5–29%)
Cerebellar cyst	Sometimes (5–29%)
Exaggerated startle response	Sometimes (5–29%)
Holoprosencephaly	Sometimes (5–29%)
Meningocele	Sometimes (5–29%)
Paralysis or weakness of one side of body	Sometimes (5–29%)
Gray matter heterotopia	Rarely (1–4%)
Cerebellar dysplasia	Not recorded
Excessive daytime sleepiness	Not recorded
Hypoplasia of the pyramidal tract	Not recorded
IQ less than 20	Not recorded
Underdevelopment of part of brain called corpus callosum	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Generalized muscle weakness	Always
Hypoglycosylation of alpha-dystroglycan	Always
Low muscle tone	Always
Low muscle tone, in neonatal onset	Always
Muscular dystrophy	Always
Proximal neurogenic muscle weakness	Always
Absent/small skeletal muscles	Very often (80–99%)
EMG abnormality	Very often (80–99%)
Flexed joint that cannot be straightened	Very often (80–99%)
Muscle degeneration	Very often (80–99%)
Muscle tissue disease	Very often (80–99%)
Muscle weakness	Very often (80–99%)
EMG: myopathic abnormalities	Often (30–79%)
Fatty replacement of skeletal muscle	Often (30–79%)
Frequent falls	Often (30–79%)
Funnel chest	Often (30–79%)
Generalized decreased muscle tone	Often (30–79%)
Gowers sign	Often (30–79%)
Muscle spasm	Often (30–79%)
Progressive muscle weakness	Often (30–79%)
Reduced muscle fiber alpha dystroglycan	Often (30–79%)
Spasticity and rigidity of muscles	Often (30–79%)
Wasting of muscles near the body	Often (30–79%)
Kyphoscoliosis	Sometimes (5–29%)
Loss of fat tissue in localized area	Sometimes (5–29%)
Congenital contracture	Not recorded
Increased skeletal muscle cells	Not recorded
Increased variability in muscle fiber diameter	Not recorded
Prominent swayback	Not recorded
Reduced spine movement	Not recorded
Scoliosis	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%)
Cat eye	Sometimes (5–29%)
Cornea of eye less than 10mm in diameter	Sometimes (5–29%)
Abnormality of eye movement	Not recorded
Blindness	Not recorded
Enlarged cornea	Not recorded
Enlarged eyeball	Not recorded
Farsightedness	Not recorded
Notched pupil	Not recorded
Optic nerve hypoplasia	Not recorded
Peters anomaly	Not recorded
Retinal atrophy	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Dandy-Walker malformation	Always
Expressionless face	Always
Meningoencephalocele	Always
Asymmetry of the posterior head	Very often (80–99%)
Abnormally small head	Often (30–79%)
Big calvaria	Often (30–79%)
Broad head shape	Often (30–79%)
Facial diplegia	Often (30–79%)
Little lower jaw	Often (30–79%)
Sloping forehead	Often (30–79%)
Bifid uvula	Sometimes (5–29%)
Cleft palate	Sometimes (5–29%)
Long, narrow head	Sometimes (5–29%)
Submucous cleft hard palate	Sometimes (5–29%)
Brain tissue sticks out through back of skull	Not recorded
Cleft upper lip	Not recorded
Encephalocele	Not recorded
Posterior fossa cyst	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Increased left ventricular end-diastolic volume	Always
Reduced left ventricular ejection fraction	Always
Stretched and thinned heart muscle	Always
Left ventricular systolic dysfunction	Very often (80–99%)
Abnormal heart rate	Often (30–79%)
Cardiac failure	Often (30–79%)
An opening in the wall separating the top two chambers of the heart	Not recorded
Myocardial fibrosis	Not recorded
Narrowing of pulmonic valve	Not recorded
Transposition of the great arteries	Not recorded

Abnormality of limbs

Trait	How often it is seen
Metatarsus valgus	Very often (80–99%)
Increased size of calf muscles	Often (30–79%)
Permanent flexion of the finger	Often (30–79%)
Peroneal muscle weakness	Often (30–79%)
Scapular muscle atrophy	Often (30–79%)
Shortening of the achilles tendon	Often (30–79%)
Wasting of limb-girdle muscle	Often (30–79%)
Club feet	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%)
Sensorineural hearing impairment	Sometimes (5–29%)
Absent ear canal	Not recorded
Small ears	Not recorded

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%)
Fluid retention	Often (30–79%)
Mildly elevated creatine kinase	Often (30–79%)

Abnormality of the genitourinary system

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

Abnormality of the respiratory system

Trait	How often it is seen
Exertional breathlessness	Often (30–79%)
Orthopnea	Often (30–79%)
Respiratory function loss	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties in infancy	Always
Absent anus	Not recorded

Abnormality of the voice

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

Constitutional symptom

Trait	How often it is seen
Fatigue	Often (30–79%)
Muscle ache	Often (30–79%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Thromboembolic stroke	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Prenatal growth deficiency	Sometimes (5–29%)

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 FKTN and how often each is seen. Find out more at hpo.jax.org.

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