Two additional cases of a recently delineated pattern of malformation, the Coffin-Siris syndrome, bring the number of reported cases to six. The features of the disorder variably include growth and mental deficiency; a coarse appearing facies with low nasal bridge, wide nose and/or mouth, and thick lips; hypoplastic nails, especially those of the fifth finger and toes; hirsutism and sparse scalp hair; and lax joints and/or hypotonia. These patients tend to have feeding problems in infancy and frequent respiratory infections. The disorder has been a sporadic one in each family. No chromosomal abnormality has been detected, and the cause remains undetermined.