Hyaline Fibromatosis Syndrome: Causes, Symptoms, and Treatment
Medically reviewed by Harsha Moole, MD, Internal Medicine. Last reviewed: October 2, 2026.
What kind of doctor treats Hyaline Fibromatosis Syndrome?
A primary care doctor is usually the first to notice the signs. Children are often referred to a medical geneticist for testing and long-term planning. Other specialists may include a dermatologist, an orthopedic surgeon, and a dentist. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What it is
Hyaline fibromatosis syndrome is a rare genetic condition. People with this condition grow small, firm bumps under the skin called hyaline fibromas, made of a thick, glassy substance called hyaline. The condition has two forms: one starts in infancy and is more severe, while the other is milder and appears later in childhood.
Symptoms
The main sign is painless, firm bumps under the skin, often on the scalp, face, neck, ears, back, fingers, and toes. Other features can include stiff joints, gum overgrowth, weak bones, and belly pain. In the severe form, babies may have trouble gaining weight and frequent loose stools.
Causes and who gets it
Hyaline fibromatosis syndrome is caused by changes in a gene called ANTXR2. A child must get one changed copy from each parent; parents who carry only one changed copy usually have no symptoms. The condition is very rare and affects boys and girls worldwide.
How doctors diagnose it
Doctors start by examining the bumps and asking about family history. A skin biopsy can show the hyaline material, and a genetic blood test can confirm the changed ANTXR2 gene. X-rays and other imaging may check bones and internal bumps.
Treatment
There is no cure, and treatment focuses on easing symptoms. Surgery can remove painful bumps, but they often grow back. Physical therapy helps stiff joints, dental care manages gum overgrowth, and a dietitian may help children who have trouble gaining weight.
When to see a doctor
Talk to a doctor if a child has firm bumps under the skin that do not go away, gums growing over the teeth, or joints that will not move normally. A baby who is not gaining weight or has frequent loose stools should also be seen. Early evaluation helps doctors plan care.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance; a concierge doctor usually charges more and often works alongside insurance. Either can spend extra time coordinating care for a rare condition, managing routine needs and referring to specialists when needed.
Common questions
Are the bumps cancerous?
No. The bumps are not cancer; they are growths made of hyaline material. A doctor may still order a biopsy to confirm the diagnosis.
Do the bumps go away on their own?
They usually do not go away without treatment. Surgery can remove them, but they often grow back over time.
Will my other children have it?
When both parents carry one changed copy of the gene, each pregnancy has a chance of producing a child with the condition. A genetic counselor can explain the exact chances for a family.
Sources
- MedlinePlus Genetics - Hyaline fibromatosis syndrome
- NIH Genetic and Rare Diseases Information Center - Hyaline fibromatosis syndrome
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
