Traits

Traits linked to SLC9A6

solute carrier family 9 member A6

The Human Phenotype Ontology links 82 traits to SLC9A6, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the nervous system

Trait	How often it is seen
Absent speech development	Always
Ataxia	Always
Degeneration of cerebrum	Always
Difficulty performing quick and alternating movements	Always
Epilepsy	Always
Interictal epileptiform activity	Always
Parkinsonism	Always
Poor fine motor coordination	Always
Profound global developmental delay	Always
Generalized-onset seizure	Very often (80–99%)
Instability or lack of coordination of central trunk muscles	Very often (80–99%)
IQ less than 20	Very often (80–99%)
Loss of brain cells	Very often (80–99%)
Loss of developmental milestones	Very often (80–99%)
Severe global developmental delay	Very often (80–99%)
Abnormal gait	Often (30–79%)
Aplasia/Hypoplasia of the corpus callosum	Often (30–79%)
Autism	Often (30–79%)
Conspicuously happy disposition	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 motor skills	Often (30–79%)
EEG abnormality	Often (30–79%)
Glabellar reflex	Often (30–79%)
Hyperactive movements	Often (30–79%)
Inability to coordinate movements when walking	Often (30–79%)
Inability to speak	Often (30–79%)
Inappropriate laughter	Often (30–79%)
Increased reflexes	Often (30–79%)
Mental deterioration	Often (30–79%)
Postural tremor	Often (30–79%)
Repetitive movements	Often (30–79%)
Resting tremor	Often (30–79%)
Slow movements	Often (30–79%)
Ventriculomegaly	Often (30–79%)
Difficulty sleeping	Sometimes (5–29%)
Epileptic encephalopathy	Sometimes (5–29%)
Happy demeanor	Not recorded
Intellectual disability	Not recorded
Intellectual disability, severe	Not recorded
Loss of ability to walk in first decade	Not recorded
Photosensitive tonic-clonic seizure	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Rigidity	Always
Abnormality of the chest	Often (30–79%)
Funnel chest	Often (30–79%)
Decreased muscle mass	Sometimes (5–29%)
Double-Jointed	Sometimes (5–29%)
Osteoporosis	Sometimes (5–29%)
Scoliosis	Sometimes (5–29%)
Flexed joint that cannot be straightened	Not recorded
Generalized decreased muscle tone	Not recorded
Low muscle tone	Not recorded
Muscle degeneration	Not recorded
Narrow chest	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Very often (80–99%)
Drooling	Very often (80–99%)
Long face	Very often (80–99%)
Narrow face	Very often (80–99%)
Open mouth	Very often (80–99%)
Thick eyebrow	Very often (80–99%)
Development of small head that was not present at birth	Often (30–79%)
Big lower jaw	Not recorded
Long nose	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Acid reflux	Often (30–79%)
Constipation	Often (30–79%)
Feeding difficulties	Often (30–79%)
Feeding difficulties in infancy	Often (30–79%)
Poor swallowing	Often (30–79%)
Loss of bowel control	Not recorded

Abnormality of the eye

Trait	How often it is seen
Cross-eyed	Always
Eye muscle paralysis	Often (30–79%)
Involuntary, rapid, rhythmic eye movements	Often (30–79%)
Vertical supranuclear gaze palsy	Often (30–79%)
Deeply set eye	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Inward turned thumb	Often (30–79%)
Abnormal feet structure	Not recorded
Slender finger	Not recorded

Growth abnormality

Trait	How often it is seen
Wasting syndrome	Very often (80–99%)
Faltering weight	Often (30–79%)
Decreased body weight	Not recorded

Abnormality of the ear

Trait	How often it is seen
Large ears	Very often (80–99%)

Abnormality of the genitourinary system

Trait	How often it is seen
Loss of bladder control	Not recorded

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 SLC9A6 and how often each is seen. Find out more at hpo.jax.org.

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