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References OMIM Gene GeneReviews HGMD HGNC
last update : 23-08-2010
Symbol LRS1
Location 3p14.3
Name Larsen syndrome 1
Corresponding gene FLNB
Other symbol(s) LAR1
Main clinical features
  • multiple dislocations of large joints, flattened facies, short fingernails, fingers anomalies( spatulate fingers)
  • bilateral dislocation of the knees, pes cavus, cylindrically shaped fingers, and characteristic facies (wide-spaced eyes, flattened nasal bridge and prominent forehead, midface hypoplasia)
  • Genetic determination autosomal dominant
    Function/system disorder osteo-articular
    congenital malformation
    Type disease
    Gene mutationChromosome rearrangementEffectComments
    missense   abnormal protein/gain of function G1691S mutation mostly frequent
  • clusters of mutations leading to substitutions in the actin-binding domain and filamin repeats 13-17 being the most common cause of Larsen
  • increased F-actin binding affinity of the mutants presents a biochemical mechanism that differentiates the autosomal dominant gain-of-function FLNB disorders from those that arise through the complete loss of FLNB protein (Sawyer 2010)