Preaxial<unk> : Ectopic SHH-expression, Hemingway mutant, mouse, right forelimb<unk>  is associated with different mutations, either mutations in a gene itself or in a cis-regulatory element responsible for the expression of a specific gene. Mutations in Hoxa- or Hoxd clusters are reported leading to<unk> . Interactions of Hoxd13 and GLI3 induce synpolydactyly, a combination of extra and consolidated digits. Other signal transduction pathways in this context are the Wnt signaling pathway or Notch. In the specific case of preaxial<unk>  (Hemingway mutant), a cis-acting mutation approximately 1Mb upstream of SHH gene has been implicated. Normally SHH is expressed in an organiser region, called the zone of polarizing activity (ZPA) on the posterior limb side. From there it diffuses anteriorly, laterally to the growth direction of the limb. In the mutant, smaller ectopic expression in a new organiser region is seen on the anterior side of the limb. This ectopic expression causes cell proliferation delivering the raw material for one or more new digits. In addition to the study of genetic causes of<unk>  limb patterning models are used to simulate the congenital disorder at the limb, being able to explain the development paths of<unk> .<unk>  can occur by itself, or more commonly, as one feature of a syndrome of congenital anomalies. When it occurs by itself, it is associated with autosomal dominant mutations in single genes, i.e. it is not a multifactorial trait. But mutation in a variety of genes can give rise to<unk> . Typically the mutated gene is involved in developmental patterning, and a syndrome of congenital anomalies results, of which<unk>  is one feature or two.<unk>  has been linked to the prenatal environment, however, with a recent study showing a relationship to maternal pollution exposure in China. Types include: OMIM Type Locus Postaxial A1 GLI3 at 7p13 Postaxial A2 13q21-q32 Postaxial A3 19p13.2-p13.1 Postaxial A4 7q22 Preaxial I ? Preaxial II SHH at 7q36 Preaxial III ? Preaxial IV GLI3 at 7p13 97 genetic syndromes have been associated with different kinds of<unk> . Ulnar<unk>  Ulnar<unk>  is often bilateral and associated with syndactyly and<unk>  of the feet. This can be a simple or complex<unk> . Ulnar<unk>  occurs as an isolated congenital condition, but can also be part of a syndrome. The syndromes which occur with ulnar<unk>  are: Trisomy 13, Greig cephalopolysyndactyly syndrome, Meckel syndrome, Ellis–van Creveld syndrome, McKusick–Kaufman syndrome, Down syndrome, Bardet–Biedl syndrome, Smith–Lemli–Opitz syndrome Radial<unk>  Type VII of radial<unk>  is associated with several syndromes: Holt–Oram syndrome, Fanconi anemia (aplastic anemia by the age of 6), Townes–Brocks syndrome, and Greig cephalopolysyndactyly (also known to occur with ulnar<unk> . Central<unk>  The syndromes associated with central<unk>  are: Bardet–Biedl syndrome, Meckel syndrome, Pallister–Hall syndrome, Legius syndrome, Holt–Oram syndrome. Also, central<unk>  can be associated with syndactyly and cleft hand.Other syndromes including<unk>  include acrocallosal syndrome, basal cell nevus syndrome, Biemond syndrome, ectrodactyly-ectodermal dysplasias-cleft lip/palate syndrome, mirror hand deformity, Mohr syndrome, oral-facial-digital syndrome, Rubinstein-Taybi syndrome, short rib<unk> , and VATER association. It can also occur with a triphalangeal thumb.
Polydactyly
Clinodactyly
Oligodactyly
Syndactyly
Brachydactyly
Sclerodactyly
Pachydermodactyly
Arachnodactyly