Multiple endocrine neoplasm type 1 (MEN1) syndrome predisposes to the development of endocrine and non-endocrine tumors with an autosomal dominant pattern of inheritance. Different mutations have been found throughout the gene with a variable phenotype expression. The proband, a Caucasian man, was admitted to our department in 2001, at the age of 51 because of a 1-yr history of diarrhoea and hypertension. He reported a previous intestinal resection for bowel occlusion with a histological diagnosis of unspecified mesenchymal neoplasia. He had also undergone a left adrenalectomy for a large nonfunctioning adrenal adenoma. Subsequently, he had suffered from gastralgia and melena; a gastroduodenoscopy showed an erosive gastritis. His family history was negative for endocrine disorders. On physical examination, multiple abdominal cutaneous lipomas and facial angiofibromas were observed. Biochemical screening revealed a primary hyperparathyroidism and an increase in circulating levels of PRL, chromogranin-A, gastrin and glucagon. The whole body computed tomography (CT) scan, the 111In-octreotide scan and the pituitary magnetic resonance imaging (MRI) did not reveal any abnormality. The presence of small neuroendocrine tumors was suspected by a positron emission tomography uptake in the epigastric region. The endoscopic ultrasound revealed a pancreatic lesion sized 1.1 cm that is under evaluation. Direct DNA sequencing analysis of the proband MEN1 gene revealed the 579delG frameshift mutation in the exon 3. The genetic screening of the family revealed the same mutation in 3 out of 5 offspring. The biochemical screening revealed some features of the MEN1 syndrome in all three of them. In conclusion, a novel frameshift MEN1 mutation was found in kindred with an apparently negative family history. Our experience confirms that MEN1 syndrome is a complex and underestimated condition, unless specifically investigated by trained specialists.