Traits

Traits linked to PHYH

phytanoyl-CoA 2-hydroxylase

The Human Phenotype Ontology links 53 traits to PHYH, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the eye

Trait	How often it is seen
Abnormal retinal pigmentation	Very often (80–99%)
Abnormality of the eye	Very often (80–99%)
Abnormality of vision	Very often (80–99%)
Clouding of the lens of the eye	Very often (80–99%)
Noninflammatory retina disease	Very often (80–99%)
Abnormality of eye movement	Often (30–79%)
Constricted pupils	Often (30–79%)
Difficulties with night vision	Often (30–79%)
Drooping upper eyelid	Often (30–79%)
Visual impairment	Often (30–79%)
Abnormally small eyeball	Sometimes (5–29%)
Involuntary, rapid, rhythmic eye movements	Sometimes (5–29%)
Progressive loss of vision	Sometimes (5–29%)
Retina degeneration	Not recorded
Rod-cone dystrophy	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Abnormal pyramidal sign	Very often (80–99%)
Ataxia	Very often (80–99%)
Paralysis or weakness of one side of body	Very often (80–99%)
Peripheral neuropathy	Very often (80–99%)
Intellectual disability, severe	Often (30–79%)
Loss of developmental milestones	Often (30–79%)
Decreased reflex response	Not recorded
Nerve damage causing decreased feeling and movement	Not recorded
Somatic sensory dysfunction	Not recorded

Abnormality of limbs

Trait	How often it is seen
Abnormal feet structure	Very often (80–99%)
Hammertoe	Often (30–79%)
Shortened long bone of hand	Often (30–79%)
High-arched foot	Sometimes (5–29%)
Limb muscle weakness	Not recorded
Short 4th long bone of foot	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
Disease of the heart muscle	Very often (80–99%)
Increased spleen size	Often (30–79%)
Heart block	Sometimes (5–29%)
Abnormal heart rate	Not recorded
Cardiac failure	Not recorded
Enlarged heart	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Abnormal skeletal development	Very often (80–99%)
Abnormal shape of end part of bone	Often (30–79%)
Low muscle tone	Often (30–79%)
Muscle degeneration	Often (30–79%)
Multiple epiphyseal dysplasia	Not recorded

Laboratory abnormality

Trait	How often it is seen
Reduced phytanic acid oxidase activity in cultured fibroblasts	Always
Laboratory abnormality	Very often (80–99%)
Elevated levels of phytanic acid	Not recorded
Increased CSF protein concentration	Not recorded

Abnormality of the integument

Trait	How often it is seen
Atypical nail growth	Very often (80–99%)
Dry skin	Very often (80–99%)
Ichthyosis	Very often (80–99%)

Abnormality of the genitourinary system

Trait	How often it is seen
Abnormal kidney function	Sometimes (5–29%)
Renal failure	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Lost smell	Very often (80–99%)

Abnormality of the ear

Trait	How often it is seen
Sensorineural hearing impairment	Very often (80–99%)

Abnormality of the respiratory system

Trait	How often it is seen
Respiratory function loss	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 PHYH and how often each is seen. Find out more at hpo.jax.org.

One test. A lifetime of answers.

From $449Free shipping · Results in 6–8 weeks

Get my Genome Test