Polydactyly is a congenital anomaly observed in humans having additional fingers or toes. The extra digit is a small piece of tissue or a bone without any joint. In majority of cases, these extra digits are incomplete and non-functioning. The extra digit is located on side of the little finger (postaxial), on the side of the thumb (preaxial) or within middle three fingers (central) of the hand. The condition of polydactyly has an incidence of one in every 500 live births.
The study presented by Kalsoom and associates describes a five generation consanguineous family with genetically inherited extra little finger and toe present on both hands and feet. Whole exome sequencing followed by Sanger sequencing led to the identification of a disease causing mutation in a novel zinc finger gene, ZNF141, mapped to the telomeric region on chromosome 4p16.3. This study may open up interesting perspectives into the function of this protein in limb development. (By Dr. Wasim Ahmad, http://jmg.bmj.com/content/early/2012/11/16/jmedgenet-2012-101219 )