Here's a post on the excellent Bibliodyssey blog that points to a collection of texts at Mesoweb about the Mayan ruins at Palenque.
Referenced publications include a scholarly work about evidence of physical deformities that may have been genetically transmitted as a result of heavy intermarriage within the god-king class in preColumbian Mayan society.
Physical Deformities in the Ruling Lineage of Palenque, and the Dynastic Implications," By Merle Greene Robertson and Marjorie S. Rosenblum Scanidizzo and John R. Scandizzo.