Ectrodactyly (also known as a split hand-split foot malformation, cleft hand or lobster claw hand) is a skeletal anomaly predominantly affecting the hands (although the feet can also be affected). The condition has a highly variable severity.
The estimated incidence is at ~ 1 in 90,000-150,000 births.
It results from a longitudinal deficiency in central digits where the mechanism is thought to be a failure of the median apical ectodermal ridge in the developing limb bud.
The most common mode of transmission is as an autosomal dominant trait, although autosomal recessive and X-linked modes of transmission also have been described.
- syndactyly, aplasia, or hypoplasia of the residual phalanges/metacarpals
- sensorineural hearing loss
- there is a deficiency or absence of one or more central digits of the hand +/- feet
- characterised by a deep V- or U-shaped central bony defect
General differential considerations include
- amniotic band sequence: usually unilateral and may be not symmetrical
- 1. Rypens F, Dubois J, Garel L et-al. Obstetric US: watch the fetal hands. Radiographics. 26 (3): 811-29. doi:10.1148/rg.263055113 - Pubmed citation
- 2. Leung KY, Maclachlan NA, Sepulveda W. Prenatal diagnosis of ectrodactyly: the 'lobster claw' anomaly. Ultrasound Obstet Gynecol. 1995;6 (6): 443-6. doi:10.1046/j.1469-0705.1995.06060443.x - Pubmed citation
- 3. Allen LM, Maestri MJ. Three-dimensional sonographic findings associated with ectrodactyly ectodermal dysplasia clefting syndrome. J Ultrasound Med. 2008;27 (1): 149-54. J Ultrasound Med (full text) - Pubmed citation