Larsen syndrome

Larsen syndrome is a rare genetic connective tissue disorder characterized by multiple large joint dislocations (typically of the knees, hips, and elbows), distinctive craniofacial features, and skeletal abnormalities. The condition was first described by Loren Larsen in 1950. The autosomal dominant form (also known as Larsen syndrome type 1) is caused by pathogenic variants in the FLNB gene, which encodes filamin B, a protein critical for skeletal development and cartilage formation. Key clinical features include congenital dislocations of large joints, a characteristic flat facial appearance with a depressed nasal bridge and widely spaced eyes (hypertelorism), frontal bossing, and a flattened midface. Skeletal abnormalities frequently include cervical vertebral anomalies (particularly cervical kyphosis, which can be life-threatening due to spinal cord compression), spatulate or cylindrical fingers, supernumerary carpal and tarsal bones, scoliosis, and short metacarpals. Patients may also exhibit cleft palate, hearing loss, and cardiovascular anomalies. Cervical spine instability is a particularly important concern, as it can lead to myelopathy and requires careful monitoring. There is no cure for Larsen syndrome, and management is multidisciplinary. Treatment focuses on orthopedic interventions including surgical stabilization of dislocated joints, correction of cervical spine abnormalities (often requiring surgical fusion), and management of scoliosis. Physical therapy and rehabilitation are essential components of care. Craniofacial surgery may be needed for cleft palate repair, and audiological monitoring is recommended. Early identification and management of cervical spine instability is critical to prevent neurological complications. With appropriate orthopedic management, many individuals with Larsen syndrome can achieve improved mobility and quality of life, though long-term follow-up is necessary.

Common questions about Larsen syndrome