Coffin-Siris syndrome

Coffin-Siris syndrome, abbreviated CSS, is a rare genetic disorder whose recognized features are developmental delay and an absent or underdeveloped fifth fingernail and toenail. It was first described in 1970 by Dr Grange S. Coffin and Dr E. Siris, whose names it carries. Early on it was known from very few people, with thirty-one reported cases by 1991, but the number of recognized cases has grown since and is now reported to be around 250 to 550 individuals. Its description lists a related condition that has to be considered when the diagnosis is worked out, Nicolaides-Baraitser syndrome, which is a different disorder with overlapping features. As with other rare genetic syndromes, the history of the condition is largely the history of clinicians gathering case reports until the pattern became recognizable.