Multiple endocrine neoplasia type 1 (MEN1) is an inherited disorder that affects the endocrine glands. Endocrine glands are different from other organs in the body because they release hormones into the bloodstream. Hormones are powerful chemicals that travel through the blood, controlling and instructing the functions of various organs. Normally, the hormones released by endocrine glands are carefully balanced to meet the body's needs.
Random postmortem studies report an incidence of 0.25%. However, clinical manifestations such as primary hyperparathyroidism have a reported incidence of multiple endocrine neoplasia type 1 (MEN1) in 1-18% of people with this disorder. Patients harboring a gastrinoma(s) have MEN1 16-38% of the time and 3% of patients with pituitary tumors have MEN1.The MEN1 gene has a high penetrance. By age 20 years, the gene is 50% penetrant and by age 40 years, 95% penetrant.
It is sometimes difficult to decide whether hyperparathyroidism in MEN1 is severe enough to need treatment, especially in a person who has no symptoms. The usual treatment is an operation to remove the three largest parathyroid glands and all but a small part of the fourth. After parathyroid surgery, regular testing of blood calcium should continue, since the small piece of remaining parathyroid tissue can grow larger and cause recurrent hyperparathyroidism.
Genomic DNA was obtained from peripheral blood leukocytes. Exons 2-10 and intronic flanking regions of the MEN 1 gene were amplified by PCR using specific primers. The amplification products were separated by electrophoresis in agarose gel, stained with ethidium bromide and examined under UV light. The DNA fragments were sequenced after being manually labeled with ddNTP33 and in latter dates, by automatic sequencing.