Crouzon syndrome
Genetic disorder causing premature skull bone fusion.
Crouzon syndrome is a genetic condition passed down in an autosomal dominant pattern. It stems from a mutation on chromosome 10, which disrupts how the body makes fibroblast growth factor receptor 2 (FGFR2). The disorder was named after the French doctor Octave Crouzon, who first identified it. He originally called it "craniofacial dysostosis"—a term that hints at the core problem: the bones of the skull and face form improperly. In a developing fetus, these bones either fuse too early or cannot expand as they should. Because normal bone growth is blocked, the skull takes on an unusual shape as different sutures close prematurely.
**Signs and symptoms**
The hallmark of Crouzon syndrome is craniosynostosis, which leads to an abnormal head shape. This can show up in various forms, including frontal bossing, trigonocephaly (from metopic suture fusion), brachycephaly (coronal suture fusion), dolichocephaly (sagittal suture fusion), plagiocephaly (unilateral early closure of lambdoid and coronal sutures), oxycephaly (fusion of coronal and lambdoidal sutures), or complex craniosynostosis (involving multiple sutures). Bulging eyes, known as exophthalmos, are common because the eye sockets are shallow after surrounding bones fuse early. Other frequent features include hypertelorism (widely spaced eyes) and a beak-like nose (psittichorhina). Many people also have external strabismus and a hypoplastic maxilla, where the midface doesn't grow enough. This makes the chin appear to jut out (mandibular prognathism), giving the face a concave look.
Most symptoms stem from the abnormal skull structure. About 30% of individuals develop hydrocephalus. Some experience sensorineural hearing loss. Vision problems often arise from how the eyes sit in their sockets; the most common issue is corneal exposure, which can lead to visual impairment. A restricted airway can cause severe breathing difficulties in some cases. Inside the mouth, common features include a narrow or high-arched palate, posterior bilateral crossbite, missing teeth (hypodontia), and crowded teeth. Because of maxillary hypoplasia, people with Crouzon syndrome typically have a significant permanent underbite.
**Causes**
Current research points to fibroblast growth factor receptors FGFR2 and FGFR3 as the main drivers of Crouzon syndrome. These two transmembrane proteins are part of a group of four receptors in
- named_after
- Octave Crouzon
- first_described_by
- Octave Crouzon
- year_first_described
- 1912
- field
- Medical genetics
- inheritance
- Autosomal dominant
- causative_genes
- FGFR2 and FGFR3
- estimated_incidence
- 1.6 per 100,000 people
Lore & Background
Crouzon syndrome was first described by Octave Crouzon in 1912. He noted the affected patients were a mother and her daughter, implying a genetic basis. The disorder was originally called 'craniofacial dysostosis,' referring to malformation of the skull and face bones. The developing fetus's skull and facial bones fuse early or are unable to expand, preventing normal bone growth.
Reader's Guide
Crouzon syndrome is the most common craniostenosis syndrome, with an estimated incidence of 1.6 out of every 100,000 people. It is caused by mutations in FGFR2 or FGFR3, leading to constitutive activation of these receptors and premature fusion of cranial sutures. Diagnosis typically occurs at birth based on physical appearance, confirmed by radiographs, MRI, CT scans, or genetic testing. Without surgical treatment, blindness and intellectual disability are typical outcomes. Surgery is used to prevent closure of sutures from damaging brain development, and treated patients generally go on to live a normal lifespan. The condition has been brought to public attention through the 2024 memoir 'A Face for Picasso: Coming of Age with Crouzon Syndrome' by Ariel Henley, covering her and her twin sister's life with the syndrome.
Did You Know?
- Crouzon syndrome is named for Octave Crouzon, a French physician who first described it in 1912.
- Approximately 30% of people with Crouzon syndrome develop hydrocephalus.
- There are 40 known mutations causing Crouzon syndrome, most of which are missense mutations.
- The 2024 memoir 'A Face for Picasso: Coming of Age with Crouzon Syndrome' covers the author's life with the condition.
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