A patient with MEN1 typical features and MEN2-like features.

Area of Science:

• Endocrinology
• Genetics
• Oncology

Background:

• Multiple Endocrine Neoplasia (MEN) type 1 (MEN1) and type 2 (MEN2) are distinct genetic disorders.
• Co-occurrence of MEN1 and MEN2 in a single patient is exceptionally rare.

Purpose of the Study:

• To report the first case of a patient with typical MEN1 clinical findings and a MEN2-like phenotype.
• To investigate the genetic basis of this rare combined presentation.

Main Methods:

• Clinical evaluation for MEN1 and MEN2 features.
• Germline DNA analysis for mutations in MEN1, CDKN1B (p27), and RET genes.
• Analysis of RET polymorphisms.

Main Results:

• The patient presented with MEN1 features, pheochromocytoma, and thickened corneal nerves.
• A germline 1132delG frameshift mutation in the MEN1 gene was identified.
• No pathogenic RET mutations were found, but RET polymorphisms Gly691Ser and Arg982Cys were present.

Conclusions:

• This case represents a unique combination of MEN1 and a MEN2-like phenotype without pathogenic RET mutations.
• Potential explanations include novel phenotype-genotype associations or modifying effects of RET variants.
• The findings may indicate shared molecular pathways between MEN1 and MEN2.