Familial isolated primary hyperparathyroidism--a multiple endocrine neoplasia type 1 variant?

Abstract

Objective: Familial isolated primary hyperparathyroidism (FIHP) is de®ned as hereditary primary hyperparathyroidism without the association of other diseases or tumors. Linkage analyses suggest that different genotypes can lead to the same phenotype of primary hyperparathyroidism. Hereditary syndromes associated with primary hyperparathyroidism are multiple endocrine neoplasia type 1 and type 2 (MEN 1 and MEN 2). In MEN 1, multiple parathyroid adenomas occur in more than 90% of the patients. Therefore, it has been suggested that FIHP could represent a variant or partial expression of MEN 1. Design: We report on a large FIHP kindred with a MEN1 gene mutation. Nineteen family members (aged 10 to 87 years) were screened. Furthermore, statistical comparison by Fisher's exact tests of FIHP families with MEN1 gene mutations and MEN 1 families with two or more endocrinopathies was carried out to investigate genotype±phenotype correlations. Methods: Mutational analysis of leucocyte DNA was carried out by direct sequencing of the complete coding region of the MEN1 gene. Screening of MEN 1 manifestations was carried out by determination of serum calcium, phosphate, parathyroid hormone, prolactin, ACTH, cortisol, IGF-I, gastrin, glucose, insulin, glucagon, serum potassium, aldosterone, plasma renin and urinary hydroxyindoleacetic acid. Results: We detected an in-frame deletion mutation in exon 8 of the MEN1 gene resulting in the deletion of one glutamine acid residue at position 363. It was found in eight individuals. Two of these family members (aged 42 and 60 years) were operated for primary hyperparathyroidism, and three (aged 13 to 40 years) showed mild hypercalcemia and parathyroid hormone levels within the upper normal range or slightly elevated, without any clinical symptoms. Two individuals (aged 12 and 19 years) were normocalcemic. One could not be tested. None of them had clinical evidence of other MEN 1 manifestations. Statistical comparison of the mutation types in families with FIHP and families with two or more MEN 1-associated endocrinopathies reported in other studies reveals a signi®cant difference. In families with FIHP, missense/in-frame mutations have been found in 87.5% of cases whereas in families with tumors in various endocrine glands these mutation types occur much less frequently (21±34%, P , 0X05). Conclusions: These studies indicate that FIHP can represent a partial MEN 1 variant and is often caused by missense/in-frame mutations. European Journal of Endocrinology 145 155±160

Menin Links Estrogen Receptor Activation to Histone H3K4 Trimethylation

“…To determine the clinical relevance of the menin-ERa interaction, 11 disease-related MEN1 mutants were tested in the yeast two-hybrid assay. These mutations have all been reported in the literature (25)(26)(27)(28)(29)(30). Most mutations disrupted the liganddependent interaction between menin and ERa (Fig.…”

Highly penetrant hereditary cancer syndromes

“…On the other hand, as its name suggests, FIHP is characterized by isolated primary HPT with no additional endocrine features, and in some families, FIHP is the initial diagnosis of what later develops into MEN 1. While 20% of families with a clinical diagnosis of FIHP carry germline MEN1 mutations (Miedlich et al, 2001), the recent identification of germline HRPT2 mutations in other FIHP families is of interest (Carpten et al, 2002). Given the differential risks between these three conditions as well as the increased risk of parathyroid carcinoma in HPT-JT, genetic diagnosis in a patient presenting with early-onset primary HPT may play a larger role in the management of these patients and their families.…”

Hiperparatireoidismo primário familiar isolado: análise e descrição de uma família com seis casos índices

“…Estudos recentes sustentam essa hipótese, demonstrando nova mutação missense no gene da NEM 1 (1,7,8) e a associação da alta freqüência dessas mutações com o HFI (7,9). A heterogeneidade genética entre as famílias com HFI não pode ser desprezada, sendo possível que algumas famílias representem, de fato variantes, verdadeiras da NEM 1 (9). Mustapha e cols.…”