Cloverleaf skull and thanatophoric dwarfism. Report of four cases, two in the same sibship.

Four cases of the cloverleaf skull syndrome are reported, 3 from Britain and 1 from Canada in a family of German/Irish descent. All cases had generalized chondrodysplastic changes and died at or just after birth. It is suggested that a cloverleaf skull is a previously unrecognized feature of thanatophoric dwarfism. Two affected girls from the same sibship are reported for the first time, suggesting an autosomal recessive type of inheritance. A review of the published material indicates that there may be three distinct syndromes in patients with the cloverleaf skull deformity. (1) The cloverleaf skull is associated with thanatophoric dwarfism and death in the perinatal period. (2) There are localized bony lesions of the skeleton outside the skull. (3) The skeleton outside the skull is normal. In the last two syndromes death may occur at birth, but survival into later childhood is the rule.