Abstract
Background: Neurofibromatosis type 1 is one of the more common rare disorders, and its atypical/segmental or mosaic forms are underdiagnosed. Thus far, only a few dozen cases of localized mosaic neurofibromatosis have undergone combined germline and somatic genetic testing for the NF1 gene.
Methods: A 65-year-old female patient was referred to our center for multiple neurofibromas on her right shoulder with a clinical diagnosis of localized mosaic neurofibromatosis. One of the neurofibromas was surgically removed.
Massively parallel sequencing and multiplex ligation-dependent probe amplification were utilized to identify the germline and somatic variants in the NF1 gene. Results: Heterozygous pathogenic NF1 gene variant c.7549C>T and multiple heterozygous intragenic NF1 gene deletions were detected in the DNA taken from the shoulder neurofibroma but not DNA from blood leukocytes or buccal smear.
Conclusion: Germline and somatic genetic testing in localized forms of neurofibromatosis are advisable since it facilitates proper genetic counseling regarding risks to offspring who could inherit a germline pathogenic variant. Another important point to consider is cancer surveillance, which is often underutilized in mosaic forms of neurofibromatosis.