OBJECTIVE: To report a new mutation of the multiple endocrine neoplasia type 1 (MEN1) gene in an Italian kindred. DESIGN: The study included the female proband, aged 50 years, affected by primary hyperparathyroidism, insulinoma and prolactinoma, and ten relatives. Blood samples were obtained for biochemical and genetic analyses. Clinical screening tests included serum glucose, ionized calcium, intact parathyroid hormone, GH, insulin and prolactin. The coding sequence, including nine coding exons and 16 splice sites, was amplified by PCR and directly sequenced. RESULTS: Two additional cases of primary hyperparathyroidism were identified among the paternal family members. The sequence analysis showed a heterozygous T to C transition at codon 444 in exon 9, resulting in a leucine to proline substitution (L444P) in the patient and in the two paternal family members with primary hyperparathyroidism. The L444P amino acid change was absent in 50 normal subjects. The mutation determined the loss of a BlnI restriction site of the wild-type sequence and the creation of a new restriction EcoRII site. The patient, but not her paternal affected relatives, also had a common heterozygous polymorphism (D418D) in exon 9. CONCLUSIONS: A new MEN1 mutation (L444P) in exon 9 has been identified; this substitution caused the loss of a BlnI restriction site and the creation of a new EcoRII site.
F Cetani, E Pardi, L Cianferotti, E Vignali, A Picone, P Miccoli, A Pinchera and C Marcocci
F Cetani, E Pardi, S Borsari, E Vignali, G Dipollina, V Braga, S Adami, A Pinchera and C Marcocci
OBJECTIVE: Calcium-sensing receptor (CaR) is a candidate gene for osteoporosis susceptibility. Several CaR polymorphisms have been identified and an association between the A986S genotype and serum calcium levels has been found in Canadian postmenopausal women. We investigated whether the presence of 986S allele was associated with bone mineral density (BMD) and osteoporotic fractures. DESIGN: The study group consisted of 164 Italian postmenopausal women without fragility fracture (Fx(-)) and 55 women with fracture (Fx(+)). METHODS: A fragment of exon 7 of CaR gene containing three polymorphisms (A986S, R990G and Q1011E) was amplified by PCR and sequenced. Anthropometric characteristics and BMD were evaluated. RESULTS: The A986S polymorphism was the most commonly observed (27.9%), whereas the other two CaR polymorphisms, R990G and Q1011E, occurred in a minority of cases (8.8 and 5.5% respectively). There was no significant difference in the frequency distribution of any CaR allele between Fx(-) and Fx(+) patients. Body mass index was found to predict BMD at the lumbar spine and femoral neck. The A986S polymorphism and Years since menopause were not independent predictors of BMD at any site. As far as fracture occurrence, there was no statistically significant difference in the prevalence of fractures between women carrying or not carrying the 986S allele. CONCLUSIONS: Our data do not support a role of A986S CaR polymorphism in BMD and in the prevalence of fragility fractures in Italian postmenopausal women.