Table 1.
Phenotypic characteristic | Number* | % Mutation positive | % Genetic component† |
Total | 202 | 11 | 32 |
Number of limbs affected | |||
4 | 20 | 30 | 55 |
3 | 6 | 33 | 50 |
2 | 72 | 17 | 44 |
1 | 104 | 2 | 17 |
Bilateral malformation | 97 | 22 | 47 |
Positive family history | 51 | 24 | 100 |
Syndrome or association | 13 | 38 | 54 |
Other non-limb malformations not classified into a syndrome | 14 | 36 | 43 |
Polydactyly | |||
Postaxial | 75 | 5 | 39 |
Preaxial | 34 | 26 | 38 |
Pre- and postaxial | 4 | 50 | 50 |
Triphalangeal thumb | 5 | 80 | 80 |
Syndactyly | 31 | 16 | 32 |
Polysyndactyly | 12 | 33 | 42 |
Longitudinal dysplasia | |||
Radial | 8 | 25 | 63 |
Ulnar | 3 | 0 | 0 |
Central | 7 | 0 | 14 |
Symbrachydactyly | 13 | 0 | 0 |
Brachydactyly | 1 | 0 | 100 |
Clinodactyly | 8 | 13 | 25 |
Camptodactyly | 4 | 25 | 25 |
Hypoplastic digits | |||
Thumb | 4 | 0 | 0 |
Other digits | 4 | 0 | 0 |
Trigger thumb | 5 | 0 | 0 |
Constriction ring syndrome | 3 | 0 | 0 |
Other | 10 | 30 | 30 |
*Totals do not add up to 202 as 24 children had multiple limb malformations which were included in between two and five categories.
†Genetic component consists of individuals with either a cytogenetic or molecularly proven diagnosis, a positive family history of congenital limb malformation (CLM), or a known genetically determined syndrome (see section: Estimation of the overall genetic contribution to CLM).