Yunis-Varon syndrome

Yunis-Varon syndrome, also called cleidocranial dysplasia with micrognathia or absent thumbs and distal aphalangia, is an extremely rare multisystem congenital disorder that affects the skeleton, the ectodermal tissues, the heart and the respiratory system. It is inherited in an autosomal recessive way, and several mutations in the FIG4 gene have been found to cause it. Some of these remove the protein function completely, while others replace amino acids at highly conserved positions. Not every FIG4 mutation produces this syndrome, as some cause forms of Charcot-Marie-Tooth disease or amyotrophic lateral sclerosis 11 instead. Affected people carry harmful FIG4 changes on both copies of the gene. The syndrome was first described by Emilio Yunis and Humberto Varon of the National University of Colombia.