A rare malformation syndrome affecting the apical structures of digits and presenting with hypo/aplasia of nails and distal phalanges. Cooks syndrome is congenital and presents with hypo/anonychia, small or absent distal phalanges and digitalization of the thumbs. Usually, the nails of digits 1-3 are progressively deformed, with anonychia congenita totalis in the digits 4-5 and in all toes. Additional features include hypoplasia of the distal phalanges in digits 2-4 with absence of the distal phalanx of digit 5. In the feet, there is absence of all distal phalanges of digits 2-5 with hypoplasia of the distal phalanx of digit 1.