In the past is was common for families to remain undiagnosed for several generations despite having been seen by doctors from a variety of disciplines.
Diagnosis in a child at 50% risk of having inherited the condition may not be easy because of the extreme variation in expression, both within and between families. Some children may have no rib anomalies whilst others have the ‘typical face’ without other signs.
For apparently isolated cased, detailed examination and x-ray investigation of the parents should be undertaken before concluding that a child’s condition is the result of a new mutation. If an adult has no physical signs, no pertinent history and normal radiology, it is unlikely that he or she has Gorlin syndrome.
Confident diagnosis is vital for subsequent surveillance for complications such as BCCs and jaw cysts, and for giving genetic information. Clinically it relies on a detailed family history, and physical and x-ray examinations.
To verify a clinical diagnosis of Gorlin syndrome, AP and lateral X-rays of the skull, an orthopantogram (OPG), chest X-rays, and spinal X-ray are usually required.
- X-rays should be avoided in childhood if the diagnosis is obvious without them or if a known mutation exists in the family.
- If X-rays have previously been taken (i.e. before the diagnosis of Gorlin syndrome is being considered) it is preferable to obtain and review the originals, rather than repeat them because individuals with the condition are susceptible to x-radiation.
- Even when present, bifid ribs, bifid vertebrae, and falx calcification are often not mentioned in formal reports of radiographic findings as these can also be normal variations in the general popultation.
- X-ray findings mey be helpful in suggesting or confirming the diagnosis in young children with cardiac fibromas, cleft lip/palate, polydactyly or macrocephaly.
Presymptomatic and pre-natal diagnosis is possible by gene tracking using DNA markers from 9q22.3-q31. For an individual family this will depend upon the availability of DNA samples from appropriate family members. There are several highly informative DNA markers within and flanking the gene, resulting in a high accuracy of prediction.
Ref: Neviod Basal Cell Carcinoma Syndrome. Synonyms: Basal Cell Nevus syndrome (BCNS), Gorlin syndrome, NBCCS. D Gareth Evans, MD, FRCP and Peter A Farndon, MD, FRCP Gene Reviews 20301330 Oct 2015
To see full article see Gene Reviews
Reviewed and verified by Medical Advisers in conjunction with the Gorlin Syndrome Group 02/04/2018. Next Review April 2019.