2003, Karl-Heinz Grzeschik, 66: Greig Cephalopolysyndactyly Syndrome, Mary Ann McLaughlin (supervising editor), NORD Guide to Rare Disorders, National Organization for Rare Disorders, Wolters Kluwer (Lippincott Williams & Wilkins), page 201,
Postaxial polydactyly is common in the hands and preaxial polydactyly in the feet.
Source: wiktionary
Pranamya Menaria (India; born August 10, 2005) has 25 in total (12 fingers and 13 toes). This is as a result of the condition Polydactyly and Syndactyly.
Source: wiktionary
The rare polydactylies, that is, not clearly only postaxial or only preaxial, are the most likely to be associated with an underlying syndrome.
Source: wiktionary
Polydactyly with a triphalangeal thumb will be described in the chapter on the triphalangeal thumb.[…]The incidence of polydactyly depends on the population studied and the definition used. Region, ethnicity and combined numbers of all polydactylies, or only radial or ulnar-sided polydactyly, provide very different incidences in published series.
Source: wiktionary