Larsen syndrome [OMIM 150 250] is an autosomal dominant skeletal dysplasia characterized by craniofacial features, large-joint dislocations and abnormalities of the extremities. Craniofacial anomalies include hypertelorism, prominence of the forehead, a depressed nasal bridge and a flattened midface. Dislocation of the large joints (knees, hips, elbows, tibio-tarsal) including anterior dislocation of at least one of the knees are the main features. The limb abnormalities include a very characteristic tapering aspect of the distal humerus. Other occasionally seen findings include short stature, cleft palate, and extraskeletal manifestations include bilateral testicular ectopy, retinal lesions and bilateral macular dysplasia, deafness, cardiac abnormalities (ventricular septal defect) and tracheomalacia.Heterozygosity for mutations in the gene encoding the filamin B (FLNB) located at chromosome 3p14.3 have been identified in a wide spectrum of osteochon-drodysplasias, including Larsen syndrome, atelosteogenesis type III (AOIII) and I, boomerang dysplasia and spondylocarpotarsal syndrome (Krakow et al., 2004). Filamin B is a cytoskeletal protein essential in modulation of the cellular cytoskeleton and has functions in signal transduction, cell division motility and transport of small molecules.Diagnosis of Larsen syndrome is usually made in the postnatal period. The prognosis is highly variable and occasionally lethal. Complications include multiple orthopedic abnormalities, instability of the cervical spine, pulmonary hypoplasia and neonatal tracheomalacia. Prenatal