Traits

Traits linked to COL2A1

collagen type II alpha 1 chain

The Human Phenotype Ontology links 350 traits to COL2A1, by body system: features seen in people with one of the gene's rare conditions.

COL2A1

Abnormality of the musculoskeletal system

Trait	How often it is seen
Abnormal cartilage collagen	Always
Beaking of vertebral bodies	Always
Coronal cleft vertebrae	Always
Disease of the joints	Always
Flattened vertebrae	Always
Funnel chest	Always
Generalized osteoporosis	Always
Hip osteoarthritis	Always
Irregular vertebral endplates	Always
Joint stiffness	Always
Limitation of joint mobility	Always
Ovoid vertebral bodies	Always
Pigeon chest	Always
Short long bone	Always
Small chest	Always
Small wings of the pelvic girdle	Always
Abnormal bone maturation	Very often (80–99%)
Abnormal bone structure	Very often (80–99%)
Abnormal shape of joints	Very often (80–99%)
Abnormal skeletal development	Very often (80–99%)
Abnormal vertebral morphology	Very often (80–99%)
Abnormality of the vertebral column	Very often (80–99%)
Bell-shaped thorax	Very often (80–99%)
Cartilage destruction	Very often (80–99%)
Death of bone due to decreased blood supply	Very often (80–99%)
Degenerative joint disease	Very often (80–99%)
Delayed bone maturation	Very often (80–99%)
Delayed maturation of end part of long bone	Very often (80–99%)
Disproportionate short-trunked short stature	Very often (80–99%)
Enlarged joints	Very often (80–99%)
Excessive inward curvature of lower spine	Very often (80–99%)
Formation of new noncancerous bone on top of existing bone	Very often (80–99%)
Hypermobility of all joints	Very often (80–99%)
Hypoplastic pelvis	Very often (80–99%)
Joint dislocation	Very often (80–99%)
Kyphoscoliosis	Very often (80–99%)
Multiple enchondromatosis	Very often (80–99%)
Muscle degeneration	Very often (80–99%)
Narrow chest	Very often (80–99%)
Scoliosis	Very often (80–99%)
Shorter than typical length between neck and abdomen	Very often (80–99%)
Spondylometaphyseal dysplasia	Very often (80–99%)
Vertebral segmentation defect	Very often (80–99%)
Abnormal bone maturation of vertebra	Often (30–79%)
Abnormal formation of the hip	Often (30–79%)
Abnormal ilium morphology	Often (30–79%)
Abnormal shape of end part of bone	Often (30–79%)
Abnormal shape of the end part of the vertebra bone	Often (30–79%)
Abnormality of the vertebral endplates	Often (30–79%)
Absent vertebral body mineralization	Often (30–79%)
Anisospondyly	Often (30–79%)
Arthritis	Often (30–79%)
Cervical instability	Often (30–79%)
Cervical spine instability	Often (30–79%)
Delayed maturation of pubic bone	Often (30–79%)
Delayed vertebral ossification	Often (30–79%)
Double-Jointed	Often (30–79%)
Flat end part of bone	Often (30–79%)
Hunched back	Often (30–79%)
Hypoplasia of the odontoid process	Often (30–79%)
Hypoplastic pubic bone	Often (30–79%)
Irregular end part of long bone	Often (30–79%)
Large end part of bone	Often (30–79%)
Limb pain	Often (30–79%)
Limited hip movement	Often (30–79%)
Morbus Scheuermann	Often (30–79%)
Narrow greater sciatic notch	Often (30–79%)
Osteochondroma	Often (30–79%)
Osteoporosis	Often (30–79%)
Short pelvis bones	Often (30–79%)
Short ribs	Often (30–79%)
Small end part of bone	Often (30–79%)
Small shoulder blade	Often (30–79%)
Thoracolumbar kyphosis	Often (30–79%)
Unossified sacrum	Often (30–79%)
Wafer-thin platyspondyly	Often (30–79%)
Wedge-shaped vertebrae	Often (30–79%)
Abnormal deposits of calcium in the brain	Sometimes (5–29%)
Anterior vertebral fusion	Sometimes (5–29%)
Atlantoaxial instability	Sometimes (5–29%)
Back pain	Sometimes (5–29%)
Barrel-shaped chest	Sometimes (5–29%)
Biconcave vertebral bodies	Sometimes (5–29%)
Biconvex vertebral bodies	Sometimes (5–29%)
Displacement of one backbone compared to another	Sometimes (5–29%)
Fused neck	Sometimes (5–29%)
Hip joint pain	Sometimes (5–29%)
Intervertebral space narrowing	Sometimes (5–29%)
Irregular iliac crest	Sometimes (5–29%)
Knee pain	Sometimes (5–29%)
Low solidness and mass of the bones	Sometimes (5–29%)
Reduced spine movement	Sometimes (5–29%)
Restricted large joint movement	Sometimes (5–29%)
Underdeveloped vertebrae	Sometimes (5–29%)
Vertebral fusion	Sometimes (5–29%)
C1-C2 vertebral abnormality	Rarely (1–4%)
Hypoplastic iliac wing	Rarely (1–4%)
Increased susceptibility to fractures	Rarely (1–4%)
Abnormal development of end part of bone	Not recorded
Anterior rib cupping	Not recorded
Broad long bones	Not recorded
C1-C2 subluxation	Not recorded
Crescent-shaped iliac bone	Not recorded
Disc-like vertebral bodies	Not recorded
Flattened, squared-off end part of tubular bones	Not recorded
Flexed joint that cannot be straightened	Not recorded
Generalized decreased muscle tone	Not recorded
Horizontal ribs	Not recorded
Hyperconvex vertebral body endplates	Not recorded
Hypoplastic ischia	Not recorded
Lethal skeletal dysplasia	Not recorded
Low muscle tone	Not recorded
Lumbar kyphoscoliosis	Not recorded
Narrow iliac wing	Not recorded
Neonatal short-trunk short stature	Not recorded
Prominent swayback	Not recorded
Schmorl's node	Not recorded
Severe platyspondyly	Not recorded
Short greater sciatic notch	Not recorded
Splayed end part of bone	Not recorded
Spondyloepimetaphyseal dysplasia	Not recorded
Spondyloepiphyseal dysplasia	Not recorded
Thin ribs	Not recorded
Thoracic kyphosis	Not recorded

Abnormality of limbs

Trait	How often it is seen
Acetabular spurs	Always
Avascular necrosis of the capital femoral epiphysis	Always
Bowed shankbone	Always
Delayed tibial epiphyseal ossification	Always
Disproportionately short upper portion of limb	Always
Dumbbell-shaped thighbone	Always
Flat acetabular roof	Always
Flat end part of innermost thighbone	Always
Heberden node	Always
Irregular wide portion of a long bone	Always
Knee osteoarthritis	Always
Limb undergrowth	Always
Limited elbow extension	Always
Outward bow-leggedness	Always
Rhizomelic arm shortening	Always
Rhizomelic leg shortening	Always
Severe limb shortening	Always
Short fingers or toes	Always
Short long bone of foot	Always
Short outermost bone of ring finger	Always
Short outermost bone of the index finger	Always
Short outermost bone of the middle finger	Always
Short outermost little finger bone	Always
Short toe	Always
Shortened long bone of hand	Always
Shortening of all middle phalanges of the fingers	Always
Abnormal neck or head of thigh bone	Very often (80–99%)
Abnormal wrist bones	Very often (80–99%)
Abnormality of femoral head development	Very often (80–99%)
Abnormality of the wide portion of a long bone	Very often (80–99%)
Aplasia/hypoplasia involving bones of the extremities	Very often (80–99%)
Bowing of the long bones	Very often (80–99%)
Corner fracture of metaphysis	Very often (80–99%)
Coxa vara	Very often (80–99%)
Flared wide portion of long bone	Very often (80–99%)
Flexion contracture of finger	Very often (80–99%)
Left and right leg differ in length or width	Very often (80–99%)
Metaphyseal cupping	Very often (80–99%)
Metaphyseal dysplasia	Very often (80–99%)
Short foot	Very often (80–99%)
Short outermost finger bone	Very often (80–99%)
Short palm	Very often (80–99%)
Small innermost thighbone end part	Very often (80–99%)
Smaller or shorter than typical limbs	Very often (80–99%)
Abnormal ulnar metaphysis morphology	Often (30–79%)
Abnormality of the calf bone	Often (30–79%)
Abnormality of the end part of the innermost thighbone	Often (30–79%)
Abnormality of the hip joint	Often (30–79%)
Abnormality of the knee	Often (30–79%)
Absent/small extremities	Often (30–79%)
Bowing of outer large bone of the forearm	Often (30–79%)
Broad wide portion of long bone	Often (30–79%)
Coxa valga	Often (30–79%)
Curvature of digit	Often (30–79%)
Delayed proximal femoral epiphyseal ossification	Often (30–79%)
Dumbbell-shaped long bone	Often (30–79%)
Enlarged wide portion of a long bone	Often (30–79%)
Flat head of thigh bone	Often (30–79%)
Internal tibial torsion	Often (30–79%)
Knock knees	Often (30–79%)
Metaphyseal enchondromatosis	Often (30–79%)
Short lower limbs	Often (30–79%)
Type E brachydactyly	Often (30–79%)
Underdeveloped inner large forearm bone	Often (30–79%)
Upper limb undergrowth	Often (30–79%)
Abnormal feet structure	Sometimes (5–29%)
Abnormal shape of long bones of hand	Sometimes (5–29%)
Abnormality of the wrist	Sometimes (5–29%)
Broad big toe	Sometimes (5–29%)
Club feet	Sometimes (5–29%)
Delayed bone maturation of the knee cap	Sometimes (5–29%)
Delayed maturation of wrist bone	Sometimes (5–29%)
Irregular acetabular roof	Sometimes (5–29%)
Limited elbow movement	Sometimes (5–29%)
Short neck of thighbone	Sometimes (5–29%)
Short thighbone	Sometimes (5–29%)
Talipes	Sometimes (5–29%)
Abnormal epiphysis morphology of the phalanges of the hand	Not recorded
Abnormality of thighbone end part	Not recorded
Absent styloid process of ulna	Not recorded
Bowed long bone in upper arm	Not recorded
Broad palm	Not recorded
Broad thumb	Not recorded
Club-shaped innermost end of thighbone	Not recorded
Cone-shaped end part of finger bones	Not recorded
Delayed distal femoral epiphyseal ossification	Not recorded
Delayed heel bone maturation	Not recorded
Dropped arches	Not recorded
Flared femoral metaphysis	Not recorded
Hip contracture	Not recorded
Hip dislocation	Not recorded
Hypoplasia of proximal radius	Not recorded
Irregular thighbone end part	Not recorded
Limitation of knee mobility	Not recorded
Long slender fingers	Not recorded
Metaphyseal dappling	Not recorded
Narrow neck of thigh bone	Not recorded
Short finger bones	Not recorded
Short thumb	Not recorded
Short tubular bones of the hand	Not recorded
Shortening of all innermost bones of the fingers	Not recorded
Small carpal bones	Not recorded
Tibial metaphyseal irregularity	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Broad head shape	Always
Cleft palate	Always
Depressed nasal bridge	Always
Frontal bossing	Always
Long philtrum	Always
Short neck	Always
Small retruded chin	Always
Zygomatic flattening	Always
Abnormal dentition	Very often (80–99%)
Decreased size of maxilla	Very often (80–99%)
Round face	Very often (80–99%)
Short nose	Very often (80–99%)
Coarse facial features	Often (30–79%)
Flat face	Often (30–79%)
Increased head circumference	Often (30–79%)
Little lower jaw	Often (30–79%)
Midface retrusion	Often (30–79%)
Pierre-Robin sequence	Often (30–79%)
Prominent forehead	Often (30–79%)
Retraction of the tongue	Often (30–79%)
Stiff neck	Often (30–79%)
Bifid uvula	Sometimes (5–29%)
Cleft soft palate	Sometimes (5–29%)
Decrease in jaw mobility	Sometimes (5–29%)
Dental cavities	Sometimes (5–29%)
Facial asymmetry	Sometimes (5–29%)
High palate	Sometimes (5–29%)
Pointed chin	Sometimes (5–29%)
Skin tag in front of the ear	Sometimes (5–29%)
Submucous cleft hard palate	Sometimes (5–29%)
Big calvaria	Rarely (1–4%)
Boxer-like facial appearance	Not recorded
Cystic hygroma	Not recorded
Decreased cranial base ossification	Not recorded
Narrow mouth	Not recorded
Nasal tip, upturned	Not recorded

Abnormality of the eye

Trait	How often it is seen
Close sighted	Always
Increased size of eyes	Always
Severe near sightedness	Always
Vitreoretinopathy	Always
Abnormal vitreous humor morphology	Very often (80–99%)
Bulging eye	Very often (80–99%)
Clouding of the lens of the eye	Very often (80–99%)
Degenerative vitreoretinopathy	Very often (80–99%)
Retinal detachment	Very often (80–99%)
Abnormality of the eye	Often (30–79%)
Absent/small lens	Often (30–79%)
Lattice retinal degeneration	Often (30–79%)
Retinal hole	Often (30–79%)
Rhegmatogenous retinal detachment	Often (30–79%)
Wide-set eyes	Often (30–79%)
Completely dislocated lens	Sometimes (5–29%)
Drooping of both upper eyelids	Sometimes (5–29%)
Glaucoma	Sometimes (5–29%)
Partially dislocated lens	Sometimes (5–29%)
Visual impairment	Sometimes (5–29%)
Visual loss	Sometimes (5–29%)
Cross-eyed	Rarely (1–4%)
High eye pressure	Rarely (1–4%)
Asteroid hyalosis	Not recorded
Blindness	Not recorded
Membranous vitreous appearance	Not recorded
Optically empty vitreous	Not recorded
Retinal thinning	Not recorded

Abnormality of the ear

Trait	How often it is seen
Sensorineural hearing impairment	Very often (80–99%)
Hearing impairment	Often (30–79%)
Low-set ears	Often (30–79%)
Tympanic membrane hypermobility	Often (30–79%)
Abnormal antitragus morphology	Sometimes (5–29%)
Conductive deafness	Sometimes (5–29%)
Ears rotated toward back of head	Sometimes (5–29%)
Narrow ear canal	Sometimes (5–29%)
Prominent ear	Sometimes (5–29%)
Small earlobe	Sometimes (5–29%)
Underfolded helix	Sometimes (5–29%)
Recurrent middle ear infection	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Belly sticks out	Always
Abdominal bloating	Very often (80–99%)
Acid reflux	Sometimes (5–29%)
Gastrostomy tube feeding in infancy	Sometimes (5–29%)
Nasogastric tube feeding in infancy	Sometimes (5–29%)
Poor suck	Sometimes (5–29%)
Inguinal hernia	Not recorded
Umbilical hernia	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Waddling gait	Always
Delayed motor skills	Often (30–79%)
Short stepped shuffling walk	Often (30–79%)
Intellectual disability	Sometimes (5–29%)
Motor delay	Sometimes (5–29%)
Pressure on spinal cord	Sometimes (5–29%)
Abnormal gait	Not recorded
Cervical myelopathy	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Breathing difficulties	Often (30–79%)
Poorly developed lungs	Often (30–79%)
Cardiorespiratory arrest	Sometimes (5–29%)
Functional respiratory abnormality	Sometimes (5–29%)
Laryngotracheomalacia	Sometimes (5–29%)
Abnormality of the respiratory system	Rarely (1–4%)
Floppy windpipe	Not recorded
Stiff lung or chest wall causing decreased lung volume	Not recorded

Growth abnormality

Trait	How often it is seen
Disproportionate short-limb short stature	Always
Short stature	Always
Disproportionate short stature	Very often (80–99%)
Growth delay	Very often (80–99%)
Severe short stature	Often (30–79%)
Disproportionate tall stature	Not recorded
Growth abnormality	Not recorded
Neonatal short-limb short stature	Not recorded

Constitutional symptom

Trait	How often it is seen
Groin pain	Always
Hip pain	Always
Joint pain	Always
Impairment of activities of daily living	Often (30–79%)

Laboratory abnormality

Trait	How often it is seen
Keratan sulfate excretion in urine	Very often (80–99%)
Fluid retention	Often (30–79%)
Hydrops fetalis	Often (30–79%)
Increased urinary type 1 collagen N-terminal telopeptide level	Rarely (1–4%)

Abnormality of the integument

Trait	How often it is seen
Pretibial blistering	Very often (80–99%)
Skin erosion	Very often (80–99%)
Erythematous plaque	Sometimes (5–29%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Iron deficiency anemia	Rarely (1–4%)

Abnormality of prenatal development or birth

Trait	How often it is seen
High levels of amniotic fluid	Often (30–79%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Mitral valve prolapse	Often (30–79%)

Abnormality of the endocrine system

Trait	How often it is seen
Abnormal circulating osteocalcin level	Rarely (1–4%)

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 COL2A1 and how often each is seen. Find out more at hpo.jax.org.

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