The UMD-MEN1 mutations database
The gene

The MEN1 gene was identified in 1997 by Chandrasekharappa et al. on chromosome 11q13.
It contains 10 exons that span approximatively 9kb of genomic DNA and encodes 610 amino acid protein referred to as menin.

It's a tumor suppressor gene, according to the Knudson two-hit hypothesis, that induced MEN 1 syndrome characterized by the co-occurrence within patient of endocrine tumors in particular parathyroid gland, entero-pancreatic tissu and anterior pituitary.
To date, more than 1300 germline or somatic mutations within the whole coding sequence of the MEN1 gene have been identified.

For MEN1, the LRG is called LRG_509 and gives two transcripts: the LRG_509t1 and the LRG_509t2.
The LRG_509t2 (corresponding to the Refseq NM_130799 and the ensemble transcript ENST00000312049) is the commonly used.

In the UMD-MEN1 database, all MEN1 variants are called according to LRG_509t2 (NM_130799, ENST00000312049).