Real time qRT-PCR analysis of MEN1 mRNA expression showed that in MEN1 parathyroid adenomas that conserved one copy of the MEN1 wild-type allele, there was around 50% reduction of MEN1 mRNA expression with respect to the control samples (normal parathyroid tissue and sporadic adenomas with the homozygous wild-type MEN1 allele), while expression of MEN1 mRNA was strongly reduced in MEN1 parathyroid adenomas with LOH where wild-type MEN1 gene was lost (Fig. 4A). The gene discussed is MEN1; the disease is parathyroid gland adenoma.