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Presymptomatic genetic screening in families with multiple endocrine neoplasia type 2
1Abteilung für Allgemeinchirurgie, Universität Hamburg, Germany.
Abstract:
Medullary thyroid carcinoma occurs sporadically or as a part of the inherited cancer syndrome multiple endocrine neoplasia (MEN) type 2. The MEN 2 gene has been identified as the RET proto-oncogene on chromosome 10. In MEN 2A, RET mutations are detectable in one of five cysteine codons within exons 10 and 11 and in MEN 2B in codon 918 (exon 16). Direct DNA testing for RET proto-oncogene mutations is the method of first choice in presymptomatic screening of MEN 2 families. Gene carriers should be offered prophylactic thyroidectomy. The process of DNA analysis for RET proto-oncogene mutations is demonstrated in one family with hereditary medullary thyroid carcinoma. RET mutations were detectable in five of the nine family members at risk.
Insights
Direct DNA testing for RET proto-oncogene mutations can identify gene carriers in families with hereditary medullary thyroid carcinoma (MTC). Early detection through genetic screening allows for timely prophylactic thyroidectomy, improving patient outcomes.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor arising from thyroid parafollicular cells.
- MTC can be sporadic or associated with inherited cancer syndromes, primarily Multiple Endocrine Neoplasia type 2 (MEN 2).
- The RET proto-oncogene on chromosome 10 is the primary genetic driver in MEN 2.
Observation:
- Specific RET proto-oncogene mutations are characteristic of MEN 2A (cysteine codons in exons 10-11) and MEN 2B (codon 918 in exon 16).
- Direct DNA testing targets these specific mutation sites for accurate genetic screening.
- A family with hereditary MTC underwent DNA analysis to identify RET proto-oncogene mutations.
Findings:
- RET mutations were identified in five out of nine at-risk family members.
- This demonstrates the utility of direct DNA testing in hereditary MTC families.
- The study confirmed the presence of RET mutations in individuals predisposed to MTC.
Implications:
- Presymptomatic genetic screening for RET mutations is crucial for families with hereditary MTC.
- Identification of gene carriers enables timely prophylactic thyroidectomy, preventing MTC development.
- This approach is the method of choice for presymptomatic diagnosis and management of MEN 2.