Table 1

Clinical characteristics of the cohort

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).