Multilayered patella: similar radiographic findings in pseudoachondroplasia and recessive multiple epiphyseal dysplasia.
A multilayered patella is a characteristic radiographic finding of recessive multiple epiphyseal dysplasia (rMED) caused by DTDST mutations. However it has been recently reported in a dominant MED case with a COL9A2 mutation. We report on a new radiographic patellar finding in a patient with pseudoachondroplasia and a heterozygous COMP mutation. It is similar to the radiographic appearance of fusing multilayered patellae in rMED cases. This led us to search the International Skeletal Dysplasia Registry for similar abnormalities. We did not observe this finding in other skeletal dysplasias or other pseudoachondroplasia cases. However we found an accessory ossification center of the patella in another pseudoachondroplasia case. Thus, we hypothesize that variable defects of cartilage extracellular matrix can result in similar abnormal patellar ossifications, and emphasize the importance of a lateral knee radiograph in patients with the pseudoachondroplasia-MED bone dysplasia group of disorders.
Medical Genetics Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA. nithiwat_v@hotmail.com
Nithiwat
N
Vatanavicharn
Ralph S
RS
Lachman
David L
DL
Rimoin
D000130:Achondroplasia / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000235:genetics*; D027321:Anion Transport Proteins / Q000235:genetics; D064236:Cartilage Oligomeric Matrix Protein; D002648:Child; D024081:Collagen Type IX / Q000235:genetics; D003937:Diagnosis, Differential; D016326:Extracellular Matrix Proteins / Q000235:genetics; D005260:Female; D005799:Genes, Dominant; D005808:Genes, Recessive; D006023:Glycoproteins / Q000235:genetics; D006579:Heterozygote; D006801:Humans; D064235:Matrilin Proteins; D009154:Mutation; D010009:Osteochondrodysplasias / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000235:genetics*; D010329:Patella / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D010641:Phenotype; D011859:Radiography; D000076988:Sulfate Transporters
D027321:Anion Transport Proteins; D064236:Cartilage Oligomeric Matrix Protein; D024081:Collagen Type IX; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D064235:Matrilin Proteins; C089651:SLC26A2 protein, human; D000076988:Sulfate Transporters; C577553:TSP5 protein, human