Multiple endocrine neoplasia type 1 (MEN1) and type 4 (MEN4)

Area of Science:

• Endocrinology
• Genetics
• Oncology

Background:

• Multiple Endocrine Neoplasia (MEN) is a group of autosomal dominant disorders characterized by tumors in two or more endocrine glands.
• Four main types of MEN are recognized: MEN1 (menin mutations), MEN2 (RET mutations), MEN3 (RET mutations), and MEN4 (CDNK1B mutations).
• Each MEN type is associated with specific tumor types, affecting glands like the parathyroid, pituitary, thyroid, pancreas, and adrenals.

Purpose of the Study:

• This review focuses on the clinical and molecular details of MEN1 and MEN4 syndromes.
• To elucidate the genetic basis and functional mechanisms of menin in MEN1 and CDNK1B in MEN4.
• To highlight the importance of genetic diagnosis for early detection and management of MEN syndromes.

Main Methods:

• Review of clinical and molecular data for MEN1 and MEN4 syndromes.
• Analysis of the role of menin protein in gene expression regulation, including its interaction with MLL and SUV39H1 complexes.
• Examination of the genetic mutations in CDNK1B associated with MEN4.

Main Results:

• MEN1 is caused by mutations in the menin gene on chromosome 11q13, affecting cell division and transcription regulation.
• Menin functions as a scaffold protein, influencing gene expression through epigenetic mechanisms like histone methylation.
• MEN4 results from heterozygous mutations in CDNK1B, which encodes the CDK inhibitor p27Kip1.

Conclusions:

• MEN1 and MEN4 syndromes have distinct genetic causes and molecular pathways.
• Understanding the molecular mechanisms of MEN1 and MEN4 is crucial for developing targeted screening and treatment strategies.
• Genetic diagnosis for MEN1 mutations aids in early identification and management of affected individuals, aligning with Knudson's two-hit hypothesis.