A novel splice site mutation of the MEN1 gene identified in a patient with primary hyperparathyroidism

Area of Science:

• Genetics
• Oncology
• Endocrinology

Background:

• Multiple endocrine neoplasia type 1 (MEN1) is a hereditary cancer syndrome caused by mutations in the MEN1 tumor suppressor gene.
• MEN1 is associated with tumors of the pituitary, parathyroid, and enteropancreatic glands.
• Accurate mutation analysis is crucial for early MEN1 diagnosis, but the clinical significance of some mutations remains unclear.

Observation:

• A previously unreported missense mutation, c.824G>T, was identified in a patient with primary hyperparathyroidism.
• Initial analysis suggested the mutation R275M caused only minor protein stability changes, raising questions about its pathogenicity.
• Further investigation using leukocyte mRNA and minigene assays revealed abnormal splicing of the MEN1 gene due to the c.824G>T mutation.

Findings:

• The c.824G>T mutation in the MEN1 gene leads to abnormally spliced menin mRNA.
• This abnormal splicing confirms that the c.824G>T mutation is causative for MEN1.
• Leukocyte mRNA analysis is a valuable method for detecting splicing mutations in the MEN1 gene.

Implications:

• This study clarifies the pathogenicity of a novel MEN1 mutation, aiding in accurate diagnosis and genetic counseling.
• The findings highlight the importance of investigating splicing defects, even when protein stability appears minimally affected.
• Leukocyte mRNA analysis offers a practical approach for identifying MEN1-associated splicing mutations, improving diagnostic capabilities for this familial cancer syndrome.