Basal cell nevus syndrome

The classic diagnostic triad for Gorlin syndrome includes: multiple basal cell carcinomas (BCC) of the skin that develop at an early age and may number in the hundreds to thousands over a lifetime; odontogenic keratocysts of the jaw; and palmar and plantar pits. Calcification of the falx cerebri (visible on skull x-ray) is present in the majority of affected individuals by age 20. Many skeletal anomalies occur in association with the disorder, including malformations of the spine and vertebrae. Other congenital malformations are present in about 5% of affected patients, most notably cleft lip and/or palate and polydactyly. Approximately 60% of affected individuals have a characteristic facial appearance with macrocephaly, frontal bossing, coarse facial features, and facial milia. Sebaceous and dermoid cysts are common. With the exception of macrocephaly, many of these features become pronounced around puberty. In addition to the extremely high risk for skin cancer (BCC), individuals are at increased risk for pediatric medulloblastoma (5% of affected patients), cardiac fibromas (2%), and ovarian fibromas in women (20%).

Tests Available

Forms and Documents

Test Details

PTCH1
  • An individual presenting with numerous basal cell carcinomas (BCCs) (>5 in a lifetime) or a BCC before age 30 years.
  • An individual with fewer than 5 BCC but with other suggestive features of nevoid basal cell carcinoma syndrome (NBCCS) may also be appropriate for testing (see features below).
  • An individual presenting with one or more associated features of NBCCS, such as lamellar calcification of the falx before age 20 years, multiple palmar pits, jaw keratocyst, childhood medulloblastoma, ovarian and/or cardiac fibroma, vertebral/rib anomalies (e.g. bifid/splayed/extra ribs; bifid vertebrae), macrocephaly, among others.
  • An unaffected individual with a family history suggestive of NBCCS when the affected individual is unavailable for his or her own genetic testing.
  • Capillary Sequencing
  • Deletion/Duplication Analysis

Ordering

205
3 weeks
2-5 mL Blood - Lavender Top Tube
Buccal Swab | Fibroblasts (separate charge for cell culture may apply) | Oral Rinse

Billing

81479x1
Yes
Yes
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References

  1. Klein, R. et al., Clinical testing for the nevoid basal cell carcinoma syndrome in a DNA diagnostic laboratory. Genet Med. 7: 611-19, 2005
  2. Wicking, C. et al., Most Germ-Line Mutations in the Nevoid Basal Cell Carcinoma Syndrome Lead to a Premature Termination of the PATCHED Protein, and No Genotype-Phenotype Correlations Are Evident. Am J Hum Genet. 60: 21-26, 1997
  3. Lindström, E. et al., PTCH Mutations: Distribution and Analyses. Hum Mutat. 27: 215-19, 2006
  4. Benhamed S and Bale S. Gorlin Syndrome: A substantial proportion of previously “missing” mutations are large PTCH deletions. ASHG Abstract presented 2008.