Table 2 Current classification of well-characterized syndactyly types

From: Syndactyly: phenotypes, genetics and current classification

ID Type/description OMIM Fingers webbing Toes webbing Inheritance Locus/gene Key reference
I-a ZD1; Zygodactyly; Weidenreich type 609815 Normal 2/3 Toes only AD 3p21.31 25
I-b SD1; Lueken type 185900 3/4 Fingers, cutaneous/bony 2/3 Toes, cutaneous AD 2q34-q36 30,31
I-c Montagu type   3/4 Fingers only, cutaneous/bony Normal AD   32
I-d Castilla type   Normal 4/5 Toes only, cutaneous AD?   2
II-a SPD1; Vordingborg type 186000 SPD, mesoaxial (3/4 fingers) SPD, postaxial (4/5 toes) AD 2q31; HOXD13 33
II-b SPD2; Debeer type 608180 SPD is central and postaxial Postaxial syndactyly AD 22q13.3; FBLN1 34
II-c SPD3; Malik type 610234 SPD is central SPD postaxial AD 14q11.2-q13 26
III SDTY3; ODDD; Johnston-Kirby type 186100 4/5 Fingers; fifth finger short Normal AD 6q21-q23; GJA1 35
IV-a SDTY4; Haas type 186200 All fingers webbed; pre-/post-axial polydactyly, cup-shaped hand Normal AD 7q36; ZRS (LMBR1) 36,37
IV-b Andersen-Hansen type   All fingers webbed; pre-/post-axial polydactyly, cup-shaped hand Variable webbing of toes with polydactyly    38
V SDTY5; Dowd type 186300 4/5 Fingers with metacarpals fusion; hypoplastic metacarpals 4/5 Mesoaxial webbing AD 2q31; HOXD13 39,40
VI Mitten type   2/5 Fingers 2/5 Toes AD   3
VII-a Cenani-Lenz type; spoon-hand type 212780 Total synostotic syndactyly with metacarpals fusion, spoon-head shape Total synostotic syndactyly with metatarsals fusion AR 11p12-p11.2; LRP4. 41,42;
VII-b Oligodactyly type   Few deformed digits Variable syndactyly of toes AD 15q13.3; GREM1-FMN1 43
VIII-a Orel-Holmes type 309630 4/5 Metacarpal fusion Normal X-R   44,45
VIII-b Lerch type   4/5 Metacarpal fusion Normal AD   46
IX MSSD; Malik-Percin type 609432 Mesoaxial synostotic syndactyly with phlanageal reduction Preaxial webbing; distal phalangeal hypoplasia AR 17p13.3 22,23
  1. Abbreviation: SPD, synpolydactyly.