Published in:
01-09-2006 | Case Report
Terminal phalangeal accessory ossification center of the thumb: an additional radiographic finding in Larsen syndrome
Authors:
Yasemin Alanay, Gulen Eda Utine, Ralph S. Lachman, Deborah Krakow, Ergul Tuncbilek
Published in:
Pediatric Radiology
|
Issue 9/2006
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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.