The main clinical characteristic is an enlarged
head (macrocephaly) with facial abnormalities such as hypertelorism, keratocysts of the
maxilla and mandible, dental dysplasia, skeletal abnormalities, calcified
falx cerebri, and typical alterations at the sole and palm “pits” that are already obvious
during infancy. The basal cell nevi occur in enormous numbers, most
often increasing in numbers around the time of puberty. Basal cell
carcinomas developed in approximately 85% of affected persons. Radiation
treatment can result in fresh crops of aggressive basal cell carcinomas. Lip
and/or palatal clefts are present in approximately 5% of cases, and mental
retardation occurs at about the same frequency. Associated congenital lung
cysts have been reported. Other skeletal abnormalities include bifid, splayed or fused ribs,
kyphoscoliosis, and spina bifida. There is also a predisposition to other
tumor formations (medulloblastomas, ovarian tumors, and, rarely, cardiac
tumors).