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Living with Cranioosteoarthropathy

A rare genetic condition with late-closing skull soft spots, clubbed fingers and toes, joint swelling, and thick bone lining.

Understanding Cranioosteoarthropathy

Cranio-osteoarthropathy (COA) is a rare genetic form of primary hypertrophic osteoarthropathy that affects the skull, bones, and joints.

It features delayed closing of skull seams and soft spots, clubbed fingers and toes (digital clubbing), joint disease (arthropathy), and thickening of the bone lining (periostosis). It starts in childhood.

Signs & symptoms

Symptoms vary from person to person. GARD lists these among the most common:

  • Late-closing soft spots on the skull
  • Clubbed toes
  • Joint pain and swelling
  • Joint stiffness
  • Arthritis
  • Mottled skin color

Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.

Diagnosis

  1. Talk with your doctor

    Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.

  2. See a specialist

    Specialists who may be involved include bone and joint specialists and genetic specialists.

  3. Consider genetic testing

    Changes in HPGD are linked to this condition. Genetic testing and counseling can help confirm a diagnosis and explain what it means for your family.

Care & treatment

Care team
Bone and joint specialists (orthopedists or orthopedic surgeons); Genetic specialists (geneticists)
Expert care
Ask about multidisciplinary care centers for rare conditions
Treatment
GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
Research
Clinical trials and observational studies may be options. See the research section below.

General information, not medical advice. Your care team makes the decisions.

Everyday life

Living with a rare condition is easier with support.

  • Connect with rare disease patient organizations for support
  • Keep notes on symptoms, changes and questions for appointments
  • Ask about patient registries that help research
  • Look into financial aid and travel resources for care visits
Bring these questions to your next doctor visit
Would HPGD gene testing help our family?
What treatments can ease joint pain and swelling?
Which specialists, such as a rheumatologist, should be involved?

Quick facts

Symptoms usually startChild
InheritanceAutosomal Recessive
GenesHPGD

It is caused by changes in the HPGD gene. It is autosomal recessive, meaning a child inherits a changed copy of the gene from each parent.

Genetic

Also known as: coa; cranio-osteoarthropathy; currarino disease; currarino idiopathic osteoarthropathy; reginato-schiapachasse syndrome

Patient organizations

Rare-disease groups that can help

Source: NIH GARD · CranioosteoarthropathyGARD ID 1564 · GARD page updated September 2026 · Plain-language summary by Know Rare; editorial review pending. General information, not medical advice.

You are more than your diagnosis

Perspectives from people navigating life with Cranioosteoarthropathy.

Explore the Cranioosteoarthropathy blog

Explore research for Cranioosteoarthropathy

Explore actively recruiting Cranioosteoarthropathy studies with HealthSpark.

HealthSpark

Find actively recruiting studies for Cranioosteoarthropathy with HealthSpark. Share your city to explore research near you.

  • Recruiting studies from ClinicalTrials.gov
  • Share your city to look for research near you
  • Eligibility is confirmed by the study team

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Powered by HealthSpark, our AI chat helper · Study information from ClinicalTrials.gov · Eligibility is confirmed by the study team.

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