Radiographic evaluation and unusual bone formations in different genetic patterns in synpolydactyly.
OBJECTIVE
To compare the radiological findings of heterozygous and homozygous subjects with synpolydactyly (SPD) and to discuss their unusual bone formations.


METHODS
Families with hand and foot SPD were examined. Genetic analysis was performed with blood samples and the pedigree was constructed. The affected individuals, especially those with distinctive phenotypic features, were invited to our orthopaedics clinic for further diagnostic studies. All participants underwent detailed clinical and X-ray examinations.


RESULTS
Of the invited patients, 16 (five female and 11 male; age range 4-37 years, mean age 10.75 years) were included in our study, and hand and foot radiographs were obtained. All subjects had bilateral hand radiographs (32 hands), and 14 had bilateral foot radiographs (28 feet). Genetic analysis revealed 12 heterozygote (75%) and four (25%) homozygote phenotypes. Among patients enrolled into the study nine (three homozygotes, six heterozygotes) had SPD of both hands and feet bilaterally (tetrasynpolydactyly). Six unusual bone formations were observed in the hands and feet: delta phalanx, delta metacarpal/metatarsal, kissing delta phalanx, true double epiphysis, pseudoepiphysis and cone-shaped epiphysis. There were major differences in radiological and clinical manifestations of homozygote and heterozygote phenotypes. The homozygous SPD presented with very distinctive unusual bone formations.


CONCLUSIONS
The existence and variety of unusual bones may indicate the severity of penetrance and expressivity of SPD.
Yucel
Aylin
A
Department of Radiology, Afyon Kocatepe University School of Medicine, 03200, Afyon, Turkey. aylin_y@yahoo.com
Kuru
Ilhami
I
Bozan
M Eray
ME
Acar
Murat
M
Solak
Mustafa
M
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D005529:Foot Bones / Q000002:abnormalities / Q000000981:diagnostic imaging*; D050276:Hand Bones / Q000002:abnormalities / Q000000981:diagnostic imaging*; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D017689:Polydactyly / Q000000981:diagnostic imaging* / Q000235:genetics; D011859:Radiography; D013576:Syndactyly / Q000000981:diagnostic imaging* / Q000235:genetics