Double germline mutations in the RET Proto-oncogene in MEN 2A and MEN 2B kindreds

Area of Science:

• Genetics
• Oncology
• Endocrinology

Background:

• Medullary thyroid carcinoma (MTC) is a rare thyroid malignancy, accounting for approximately 10% of thyroid cancers.
• MTC can be sporadic or associated with inherited syndromes like Multiple Endocrine Neoplasia (MEN) types 2A and 2B.
• Germline mutations in the RET proto-oncogene are common in familial MTC, typically affecting specific exons.

Purpose of the Study:

• To investigate the occurrence and implications of multiple germline mutations in the RET proto-oncogene in MEN 2 families.
• To identify and characterize novel genetic alterations contributing to MTC development.

Main Methods:

• Genetic analysis of RET proto-oncogene in DNA samples from two MEN 2 families.
• Detection of germline mutations using sequencing techniques.
• Correlation of identified mutations with clinical presentation of MEN 2 syndromes.

Main Results:

• Two MEN 2 families were found to harbor double germline mutations in the RET proto-oncogene.
• In one MEN 2A family, mutations were detected in exons 10 (Cys620Phe) and 13 (Tyr791Phe).
• In a MEN 2B family, a second mutation in exon 13 (Tyr791Phe) was identified alongside the classical exon 16 (Met918Thr) mutation.

Conclusions:

• MEN 2 syndromes can be caused by double germline mutations in the RET proto-oncogene.
• These findings add to the limited global data on families with multiple RET germline mutations.
• This expands the genetic landscape of MTC and associated hereditary syndromes.