Traits

Traits linked to GDAP1

ganglioside induced differentiation associated protein 1

The Human Phenotype Ontology links 92 traits to GDAP1, 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 reflexes	Always
Decreased motor nerve conduction velocity	Always
Decreased number of large peripheral myelinated nerve fibers	Always
Decreased number of peripheral myelinated nerve fibers	Always
Decreased reflex response	Always
Decreased sensation in extremities	Always
Decreased sensory nerve conduction velocity	Always
Decreased touch sensation in extremities	Always
Impaired distal vibration sensation	Always
Impaired pain sensation	Always
Onion bulb formation	Always
Peripheral demyelination	Always
Peripheral neuropathy	Always
Segmental peripheral demyelination	Always
Axonal loss	Very often (80–99%)
Chronic axonal neuropathy	Very often (80–99%)
Decreased nerve conduction velocity	Very often (80–99%)
Decreased number of small peripheral myelinated nerve fibers	Very often (80–99%)
Impaired touch sensation	Very often (80–99%)
Impaired vibratory sensation	Very often (80–99%)
Nerve damage causing decreased feeling and movement	Very often (80–99%)
Peripheral axonal degeneration	Very often (80–99%)
Poor fine motor coordination	Very often (80–99%)
Poor gross motor coordination	Very often (80–99%)
Abnormal gait	Often (30–79%)
Clumsy tandem walking	Often (30–79%)
Clusters of axonal regeneration	Often (30–79%)
Diminished deep tendon reflex	Often (30–79%)
Impaired distal proprioception	Often (30–79%)
Inability to walk	Often (30–79%)
Loss of ability to walk	Often (30–79%)
Motor delay	Often (30–79%)
Unsteady walk	Often (30–79%)
Weakness of the vocal cords	Often (30–79%)
Demyelinating peripheral neuropathy	Sometimes (5–29%)
Motor conduction block	Sometimes (5–29%)
Axonal degeneration	Not recorded
Axonal regeneration	Not recorded
Basal lamina onion bulb formation	Not recorded
CNS hypomyelination	Not recorded
Decreased distal sensory nerve action potential	Not recorded
High stepping	Not recorded
Hypertrophic nerve changes	Not recorded
Inability to walk by childhood/adolescence	Not recorded

Abnormality of limbs

Trait	How often it is seen
Proximal lower limb muscle weakness	Always
Proximal upper limb muscle weakness	Always
Abnormal feet structure	Very often (80–99%)
Distal lower limb muscle weakness	Very often (80–99%)
Distal upper limb muscle weakness	Very often (80–99%)
High-arched foot	Very often (80–99%)
Club feet	Often (30–79%)
Club foot on both sides	Often (30–79%)
Decreased Achilles reflex	Often (30–79%)
Decreased arm strength	Often (30–79%)
Hammertoe	Often (30–79%)
Hand muscle degeneration	Often (30–79%)
Hand muscle weakness	Often (30–79%)
Hyporeflexia of upper limbs	Often (30–79%)
Intrinsic hand muscle atrophy	Often (30–79%)
Joint contracture of the hand	Often (30–79%)
Limited movement of hinge joints	Often (30–79%)
Limited wrist movement	Often (30–79%)
Lower limb muscle weakness	Often (30–79%)
Peroneal muscle weakness	Often (30–79%)
Quadriceps weakness	Often (30–79%)
Split hand	Often (30–79%)
Ulnar claw	Often (30–79%)
Weak shoulder muscles	Sometimes (5–29%)
Foot drop	Not recorded
Limb muscle weakness	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Weakness of outermost muscles	Always
Distal muscle wasting	Very often (80–99%)
EMG abnormality	Very often (80–99%)
Muscle degeneration	Very often (80–99%)
Abnormality of the vertebral column	Often (30–79%)
Angulated muscle fibers	Often (30–79%)
Fiber type grouping	Often (30–79%)
Flexed joint that cannot be straightened	Often (30–79%)
Frequent falls	Often (30–79%)
Kyphoscoliosis	Often (30–79%)
Neuropathic spinal arthropathy	Often (30–79%)
Proximal neurogenic muscle weakness	Often (30–79%)
Type 1 muscle fiber predominance	Often (30–79%)
Abnormality of the chest	Sometimes (5–29%)
Denervation of the diaphragm	Sometimes (5–29%)
Generalized low muscle tone in neonate	Sometimes (5–29%)
Scoliosis	Sometimes (5–29%)
EMG: neuropathic changes	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Weakness of facial musculature	Rarely (1–4%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Abnormal heart rate	Often (30–79%)

Abnormality of the respiratory system

Trait	How often it is seen
Stiff lung or chest wall causing decreased lung volume	Sometimes (5–29%)

Abnormality of the voice

Trait	How often it is seen
Hoarse voice	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 GDAP1 and how often each is seen. Find out more at hpo.jax.org.

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