Basal cell nevus syndrome


First reported in 1894 by Jarisch and White and first described in 1960 by Gorlin, basal cell nevus syndrome (BCNS) is a rare genetic disorder that affects many systems in the body, including the integumentary (skin), skeletal, reproductive, urinary, endocrine, and nervous systems. Basal cells are located in the outer layer of the skin. BCNS may result in the development of more than two types of basal cell carcinoma, a cancer of the outer layer of the skin that usually occurs prior to the age of 30; cysts in the jaw; eye or facial abnormalities; abnormalities in the rib cage and vertebrae (the spinal column); increased risk of cardiac and uterine fibromas (noncancerous tumors); increased incidence of medulloblastoma, the most common childhood central nervous system tumor; and pits in the palms of the hands and soles of the feet. Symptoms of BCNS may be apparent at birth or may develop in the second or third decade of life.
BCNS is caused by a mutation or defect in the PTCH1 gene. Mutations in this gene have also been identified in individuals with basal cell carcinomas and medulloblastoma, which is the most common childhood central nervous system tumor. Medulloblastomas form between the brain stem and the cerebellum. BCNS is inherited or passed down among family members as an autosomal dominant trait.
This gene was first identified in fruit flies, an organism popularly used by biologists to study development. The PTCH1 gene was determined to be important in the growth and development of many parts of the body. For example, correct functioning of the PTCH1 gene is needed for the proper development of the arms, legs, and spinal cord. The PTCH1 gene produces the Patched-1 protein, which interacts with a protein called Sonic Hedgehog to transmit signals in the body that allow its proper functioning. Specifically, the interaction is important in early development and plays a role in cell growth, cell specialization, and determining the shape of many different parts of the developing body.
BCNS is estimated to occur in one out of every 56,000-164,000 people. The prevalence is likely to be higher among young people with basal cell carcinomas. BCNS appears to affect males and females of all races and ethnicities equally. While exact death rates are not available, patients with BCNS tend to die of skin cancer or complications of cancer.
There is no cure for BCNS. Treatment aims to reduce symptoms and prevent or treat complications.

Related Terms

Basal cell carcinoma, basal cell naevus syndrome, BCC, BCNS, bifid rib, broad nose, crossed eyes, cysts, fifth phacomatosis, genetic disorder, Gorlin syndrome, Gorlin's syndrome, Gorlin-Goltz syndrome, hedgehog, hydrocephalus costovertebral dysplasia and Sprengel anomaly, kyphosis, medulloblastoma, multiple basal cell nevi odontogenic keratocysts and skeletal anomalies, NBCCS, naevoid basal cell carcinoma syndrome, nevoid basal cell carcinoma syndrome, palmar and plantar pits, Patched-1, photodynamic therapy, PTCH1 gene, scoliosis, smoothened, Sonic hedgehog, underbite.