How is Larsen syndrome inherited?

Larsen syndrome follows an autosomal dominant inheritance pattern. This means inheriting just one copy of the altered gene from either parent can cause the condition.

How rare is Larsen syndrome?

Larsen syndrome is classified as rare. The estimated prevalence is approximately 1-9 in 1,000,000. Because rare disease data can be limited, actual numbers may differ from published estimates.

How is Larsen syndrome diagnosed?

Information about diagnosis is currently limited for this condition.

Are there treatments for Larsen syndrome?

Information about treatment is currently limited for this condition.

What complications can arise from Larsen syndrome?

Larsen syndrome can lead to several complications, especially related to joint dislocations and spine issues. People with this condition may experience chronic pain, limited mobility, and difficulties with daily activities due to joint instability. Additionally, scoliosis can worsen over time, requiring careful monitoring and potential interventions.

How does Larsen syndrome affect daily life and activities?

Living with Larsen syndrome can impact daily life in various ways. Individuals may need assistance with certain activities due to joint dislocations or foot deformities, which can make walking or standing difficult. It's important for families to work with healthcare providers to create a supportive environment that accommodates these challenges.

What is the life expectancy for someone with Larsen syndrome?

Currently, there is limited information about the life expectancy of individuals with Larsen syndrome. The prognosis can vary widely based on the severity of symptoms and complications. Regular medical care and management of symptoms can help improve quality of life and potentially influence longevity.

Are there specific specialists that should be involved in managing Larsen syndrome?

Yes, individuals with Larsen syndrome may benefit from a team of specialists. Orthopedic doctors can help manage joint dislocations and skeletal issues, while geneticists can provide insights into the genetic aspects of the condition. Additionally, physical therapists can assist with mobility and strength training, making daily activities easier.

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Larsen syndrome - Clinical Profile, Genes & Research | Kisho | Kisho

Rare Disease

Larsen syndrome

MONDO:0007875

Also known as:dominant Larsen syndromeLRSautosomal dominant Larsen syndrome

Overview

A rare skeletal dysplasia characterized by congenital dislocation of large joints, foot deformities, cervical spine dysplasia, scoliosis, spatula-shaped distal phalanges and distinctive craniofacial abnormalities, including cleft palate.

GeneticsAutosomal dominant · FLNB (chr 3)

OnsetCONGENITAL

Clinical Presentation

Built from Human Phenotype Ontology (HPO) phenotype annotations and GeneReviews clinical descriptions. Features represent findings documented across known cases — not an exhaustive list of possible symptoms.

Features include very common findings: Spatulate thumbs, Midface retrusion, Hip dislocation, and Knee dislocation; and common findings: Short stature, Elbow dislocation, Vertebral fusion, and Sideways curvature of the spine (scoliosis) and others. 49 total HPO annotations.

Organ System	Phenotype Count	Example Features
Bones and joints	7	Joint hypermobility, Vertebral fusion, Cervical kyphosis

Genetic Landscape

Assembled from HGNC gene records, ClinGen gene-disease validity evidence, and ClinVar pathogenic variant data. Validity classifications reflect the strength of published evidence linking each gene to this disease.

FLNB encodes filamin B (2,602 aa). Connects cell membrane constituents to the actin cytoskeleton. May promote orthogonal branching of actin filaments and links actin filaments to membrane glycoproteins. Highest expression in Nerve Tibial (192.4 TPM) and Uterus (108.4 TPM).

Larsen syndrome is associated with mutations in the FLNB gene on chromosome 3.

FLNB is classified as a druggable target (Transporter category) with score 0.0.

GeneReviews

Diagnosis

Drawn from GeneReviews diagnostic guidelines, newborn screening panel status (RUSP), and ClinGen gene-disease validity classifications. Reflects current clinical evidence and consensus where available.

GeneReviews

Diagnostic Criteria

Formal diagnostic criteria for FLNB-related disorders have not been established. The FLNB-related disorders can be divided into two groups of conditions caused by loss of function or gain of function of filamin-B. Biallelic loss-of-function pathogenic variants in FLNB cause spondylocarpotarsal synostosis syndrome (FLNB-SCT). Monoallelic gain-of-function pathogenic variants in FLNB cause a spectrum of phenotypic severity ranging from apparently isolated clubfoot to Larsen syndrome (FLNB-LS), atelosteogenesis type 3 (FLNB-AO3), and atelosteogenesis type 1 (FLNB-AO1), which is perinatal lethal. For the purposes of this GeneReview, the previously described entities Piepkorn dysplasia and boomerang dysplasia are subsumed under the FLNB-AO1 spectrum.

Treatment

Compiled from FDA-approved drug records, orphan drug designations, and FDA Adverse Event Reporting System (FAERS) safety data. GeneReviews management guidance is included where available.

No approved treatments are currently available for Larsen syndrome. The disease remains an area of unmet medical need.

GeneReviews

Management Guidelines

No clinical practice guidelines for FLNB-related disorders have been published. In the absence of published guidelines, the following recommendations are based on the authors' personal experience managing individuals with this disorder.

Evaluations Following Initial Diagnosis

To establish the extent of disease and needs in an individual diagnosed with an FLNB-related disorder, the evaluations summarized (if not performed as part of the evaluation that led to the diagnosis) are recommended.

Prognosis

Based on GeneReviews surveillance recommendations, HPO phenotype frequency and severity annotations, and published prevalence estimates from Orphanet and OMIM.

GeneReviews

Surveillance Guidelines

To monitor existing manifestations, the individual's response to supportive care, and the emergence of new manifestations, the evaluations summarized in are recommended. Table 6. FLNB-Related Disorders: Recommended Surveillance

Research Landscape

Sourced from ClinicalTrials.gov and PubMed. Publication types are classified using NLM-curated article metadata; research type breakdowns reflect the nature of published work for this disease.

No clinical trials have been registered for Larsen syndrome.

13 publications have been identified in PubMed for Larsen syndrome. Research spans Case Report / Case Series (46%), Review / Meta-Analysis (23%), and Epidemiology / Natural History (15%).

Research Type	Count	% of Total
Patient case studies	6	46%

Data assembled from 7 of 12 sources · Last updated Sep 20, 2026, 8:40 AM UTC

MONDOHPOClinicalTrials.govFDAPubMedHGNCClinVarClinGenGeneReviewsOrphanetOMIMRUSP

Medical References

External Resources

OMIM

Online Mendelian Inheritance in Man

OMIM:150250

Orphanet

European rare disease database

Orphanet:503

GARD

Genetic and Rare Diseases Info Center

GARD:6860

Questions for Your Care Team

→Should I pursue genetic testing for FLNB, and what would the results mean for my family?
→Are there specialists or centers of excellence for this condition in my area?
→Is there a patient registry I should consider joining?

FAQ

Frequently Asked Questions

Common questions about Larsen syndrome

Larsen syndrome is a rare skeletal disorder that affects the development of bones and joints. It is characterized by congenital dislocation of large joints and distinctive facial features. Many people with this condition may have abnormalities in the cervical spine and other parts of the skeletal system. In addition to joint dislocations, individuals often show foot deformities, a curved spine (scoliosis), and uniquely shaped bones in the fingers (spatula-shaped distal phalanges). There may also be craniofacial abnormalities, such as a cleft palate, that contribute to the overall presentation of the condition.

Common symptoms of Larsen syndrome include congenital dislocation of large joints, foot deformities, cervical spine dysplasia, and scoliosis. People with this disorder may also display unique bone shapes in their hands and craniofacial differences such as cleft palate.

Larsen syndrome is associated with changes in the FLNB gene. These gene variations lead to the condition being inherited in an autosomal dominant pattern. This means that a change in just one copy of the gene can lead to the development of the syndrome. Associated genes include FLNB.

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GeneReviews

Differential Diagnosis

FLNB-related spondylocarpotarsal synostosis syndrome. See . Table 2. Genes of Interest in the Differential Diagnosis of FLNB-Related Spondylocarpotarsal Synostosis Syndrome

Gene(s)	Disorder	MOI	Features of Disorder
TBX6	Spondylocostal dysostosis (See Spondylocostal Dysostosis, Autosomal Recessive.)	AR(AD)1	Vertebral dysplasia
Rib anomalies FGF9GDF5GDF6NOG	Multiple synostoses syndrome (OMIM PS186500)	AD	Vertebral dysplasia
GDF6	GDF6-related Klippel-Feil syndrome (OMIM 118100)	AD	Vertebral, carpal, tarsal fusions
MYH3	MYH3-related SCT w/contractures pterygia (OMIM 178110 618469)	ADAR	Vertebral, carpal, tarsal fusions
RFLNA	RFLNA-related SCT2	AR	Vertebral, carpal, tarsal fusions
Genes of Interest in the Differential Diagnosis of FLNB-Related Larsen Syndrome Gene	Disorder	MOI	Features of Disorder Overlapping w/FLNB-LS
B3GAT3	B3GAT3-related multiple joint dislocations, short stature, craniofacial dysmorphisms, skeletal dysplasia, w/ or w/o heart defects (OMIM 245600)	AR	Joint dislocations
B4GALT7	B4GALT7-related Ehlers-Danlos syndrome, spondylodysplastic type 1 (OMIM 130070)	AR	Joint dislocations
BPNT2(IMPAD1)	BPNT2-related chondrodysplasia w/congenital joint dislocations (OMIM 614078)	AR	Joint dislocations
CANT1	CANT1-related Desbuquois dysplasia (w/accessory ossification center in digit 2) (OMIM 251450)	AR	Joint dislocations
CHST3	CHST3-related chondrodysplasia w/congenital joint dislocations1	AR	Joint dislocations

Source: GeneReviews — "FLNB-Related Disorders"

Kisho

Larsen syndrome

Overview

Clinical Presentation

Genetic Landscape

Diagnosis

Diagnostic Criteria

Treatment

Management Guidelines

Evaluations Following Initial Diagnosis

Prognosis

Surveillance Guidelines

Research Landscape

Medical References

External Resources

OMIM

Orphanet

GARD

Questions for Your Care Team

Questions for Your Care Team

FAQ

Frequently Asked Questions

Clinical Guidance

Explore clinical features

Clinical Guidance

Penetrance

Differential Diagnosis

Orthopedic

Pulmonology

Audiology

Ophthalmology

Dental

Genetic counseling

Therapies Under Investigation

Clinical Trials

Recent Publications

Latest News & Developments

Expanding the Genetic and Clinical Spectrum of GZF1-Related Phenotype: A Specific Ocular and Skeletal Disorder Distinguishable From Larsen Syndrome.

Larsen syndrome

Overview

Clinical Presentation

Genetic Landscape

Diagnosis

Diagnostic Criteria

Treatment

Management Guidelines

Evaluations Following Initial Diagnosis

Prognosis

Surveillance Guidelines

Research Landscape

Medical References

External Resources

OMIM

Orphanet

GARD

Related Diseases

Questions for Your Care Team

Questions for Your Care Team

FAQ

Frequently Asked Questions

What is Larsen syndrome?

What are the symptoms of Larsen syndrome?

What causes Larsen syndrome?

How is Larsen syndrome inherited?

How rare is Larsen syndrome?

How is Larsen syndrome diagnosed?

Are there treatments for Larsen syndrome?

What complications can arise from Larsen syndrome?

How does Larsen syndrome affect daily life and activities?

What is the life expectancy for someone with Larsen syndrome?

Are there specific specialists that should be involved in managing Larsen syndrome?

Clinical Guidance

Explore clinical features

Clinical Guidance

Penetrance

Differential Diagnosis

Orthopedic

Pulmonology

Audiology

Ophthalmology

Dental

Genetic counseling

Therapies Under Investigation

Clinical Trials

Recent Publications

Latest News & Developments

Expanding the Genetic and Clinical Spectrum of GZF1-Related Phenotype: A Specific Ocular and Skeletal Disorder Distinguishable From Larsen Syndrome.