title: Terminal phalangeal accessory ossification center of the thumb: an additional radiographic finding in Larsen syndrome.
abstract: Larsen syndrome is an autosomal-dominant disorder characterized by multiple joint dislocations, vertebral anomalies and dysmorphic facies. Both autosomal-dominant and autosomal-recessive forms of the disorder have been proposed. Individuals with autosomal-dominant Larsen syndrome have characteristic "cylindrical-shape" thumbs caused by broad, shortened phalanges. Autosomal-dominant Larsen syndrome results from heterozygosity for mutations in filamin B, a cytoskeletal protein involved in multicellular processes. We report here a patient with a duplicated or accessory distal thumb phalanx and multiple large joint dislocations who was shown to be heterozygous for a filamin B mutation predicting the amino acid substitution G1691S. This adds a new radiographic finding, duplicated or accessory distal phalanx, to the radiographic abnormalities seen in this rare dominant disorder.
authors.affiliation: Clinical Genetics Unit, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey. yalanay@hacettepe.edu.tr
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Alanay
authors.forename: Gulen Eda
authors.initials: GE
authors.lastname: Utine
authors.forename: Ralph S
authors.initials: RS
authors.lastname: Lachman
authors.forename: Deborah
authors.initials: D
authors.lastname: Krakow
authors.forename: Ergul
authors.initials: E
authors.lastname: Tuncbilek
mesh_terms: D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging; D005260:Female; D006228:Hand Deformities, Congenital / Q000000981:diagnostic imaging*; D006801:Humans; D007231:Infant, Newborn; D011859:Radiography; D013577:Syndrome; D013933:Thumb / Q000002:abnormalities* / Q000000981:diagnostic imaging*