Purpose: The UK 100,000 Genomes Project offered participants screening for additional findings (AFs) in genes associated with familial hypercholesterolemia (FH) or hereditary cancer syndromes including breast/ovarian cancer (HBOC), Lynch, familial adenomatous polyposis, MYH-associated polyposis, multiple endocrine neoplasia (MEN), and von Hippel-Lindau. Here, we report disclosure processes, manifestation of AF-related disease, outcomes, and costs.
Methods: An observational study in an area representing one-fifth of England.
Familial hypocalciuric hypercalcemia type 2 (FHH2) and autosomal dominant hypocalcemia type 2 (ADH2) are due to loss- and gain-of-function mutations, respectively, of the GNA11 gene that encodes the G protein subunit Gα11, a signaling partner of the calcium-sensing receptor (CaSR). To date, four probands with FHH2-associated Gα11 mutations and eight probands with ADH2-associated Gα11 mutations have been reported. In a 10-year period, we identified 37 different germline GNA11 variants in >1200 probands referred for investigation of genetic causes for hypercalcemia or hypocalcemia, comprising 14 synonymous, 12 noncoding, and 11 nonsynonymous variants.
View Article and Find Full Text PDFObjective: The autoimmune polyendocrine syndrome type 1 (APS-1) is an autosomal recessive disorder characterised by immune dysregulation and autoimmune endocrine gland destruction. APS-1 is caused by biallelic mutations affecting the autoimmune regulator (AIRE) gene on chromosome 21q22.3, which facilitates immunological self-tolerance.
View Article and Find Full Text PDFpathogenic germline variants (PGVs) are identified in up to 10% of patients with paraganglioma and phaeochromocytoma and up to 30% with wild-type gastrointestinal stromal tumours. Most PGV carriers present with an apparently sporadic tumour, but often the pathogenic variant has been inherited from parent who has the variant, but has not developed any clinical features. Studies of PGV carriers suggest that lifetime penetrance for SDHA-associated tumours is low, particularly when identified outside the context of a family history.
View Article and Find Full Text PDFMultiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined occurrence of parathyroid tumors, pituitary adenomas, and pancreatic neuroendocrine neoplasms (PNENs). MEN1 is caused by germline mutations in > 75% of patients, and the remaining 25% of patients may have mutations in unidentified genes or represent phenocopies with mutations in genes such as cell cycle division 73 (, the calcium sensing receptor (, and cyclin-dependent kinase inhibitor 1B (, which are associated with the hyperparathyroidism-jaw tumor syndrome, familial hypocalciuric hypercalcemia type 1, and MEN4, respectively. Here, we report a heterozygous c.
View Article and Find Full Text PDFAdvances in technology have led to a massive expansion in the capacity for genomic analysis, with a commensurate fall in costs. The clinical indications for genomic testing have evolved markedly; the volume of clinical sequencing has increased dramatically; and the range of clinical professionals involved in the process has broadened. There is general acceptance that our early dichotomous paradigms of variants being pathogenic-high risk and benign-no risk are overly simplistic.
View Article and Find Full Text PDFContext: Familial hypocalciuric hypercalcemia type 1 (FHH1) is caused by loss-of-function mutations of the calcium-sensing receptor (CaSR) and is considered a benign condition associated with mild-to-moderate hypercalcemia. However, the children of parents with FHH1 can develop a variety of disorders of calcium homeostasis in infancy.
Objective: The objective of this work is to characterize the range of calcitropic phenotypes in the children of a mother with FHH1.
Context: Autosomal dominant hypocalcemia types 1 and 2 (ADH1 and ADH2) are caused by germline gain-of-function mutations of the calcium-sensing receptor (CaSR) and its signaling partner, the G-protein subunit α 11 (Gα 11), respectively. More than 70 different gain-of-function CaSR mutations, but only 6 different gain-of-function Gα 11 mutations are reported to date.
Methods: We ascertained 2 additional ADH families and investigated them for CaSR and Gα 11 mutations.
The calcium-sensing receptor (CaSR) is a homodimeric G-protein-coupled receptor that signals via intracellular calcium (Ca2+i) mobilisation and phosphorylation of extracellular signal-regulated kinase 1/2 (ERK) to regulate extracellular calcium (Ca2+e) homeostasis. The central importance of the CaSR in Ca2+e homeostasis has been demonstrated by the identification of loss- or gain-of-function CaSR mutations that lead to familial hypocalciuric hypercalcaemia (FHH) or autosomal dominant hypocalcaemia (ADH), respectively. However, the mechanisms determining whether the CaSR signals via Ca2+i or ERK have not been established, and we hypothesised that some CaSR residues, which are the site of both loss- and gain-of-function mutations, may act as molecular switches to direct signalling through these pathways.
View Article and Find Full Text PDFContext: Acromegaly usually is suspected on clinical grounds. Biochemical confirmation is required to optimize therapy, but there are other differential diagnoses.
Case Description: We describe a 24-year-old Uzbek man who presented with many clinical symptoms and signs of apparent acromegaly.
G-protein subunit α-11 (Gα ) couples the calcium-sensing receptor (CaSR) to phospholipase C (PLC)-mediated intracellular calcium (Ca ) and mitogen-activated protein kinase (MAPK) signaling, which in the parathyroid glands and kidneys regulates parathyroid hormone release and urinary calcium excretion, respectively. Heterozygous germline loss-of-function Gα mutations cause familial hypocalciuric hypercalcemia type 2 (FHH2), for which effective therapies are currently not available. Here, we report a novel heterozygous Gα germline mutation, Phe220Ser, which was associated with hypercalcemia in a family with FHH2.
View Article and Find Full Text PDFPurpose: Several new gene mutations have been reported in recent years to be associated with a risk of familial pheochromocytoma. However, it is unclear as to whether extensive genetic testing is required in all patients.
Methods: The clinical data of consecutive patients operated for pheochromocytoma over a decade in a tertiary referral center were reviewed.
Bilateral adrenal macronodular hyperplasia (BMAH) is a rare form of Cushing's syndrome characterised by the presence of bilateral secretory adrenal nodules and hypercortisolism. Familial studies support a genetic basis for BMAH, and the disease has been linked to mutations in ARMC5, a gene shown to have a tumour suppressor-like action in the development of adrenal nodules. This study aimed to investigate whether ARMC5 mutations play a role in the development of incidentally discovered bilateral adrenal nodules.
View Article and Find Full Text PDFAutosomal dominant hypocalcemia (ADH) is characterized by hypocalcemia, inappropriately low serum parathyroid hormone concentrations and hypercalciuria. ADH is genetically heterogeneous with ADH type 1 (ADH1), the predominant form, being caused by germline gain-of-function mutations of the G-protein coupled calcium-sensing receptor (CaSR), and ADH2 caused by germline gain-of-function mutations of G-protein subunit α-11 (Gα11 ). To date Gα11 mutations causing ADH2 have been reported in only five probands.
View Article and Find Full Text PDFFamilial hypocalciuric hypercalcemia (FHH) is a genetically heterogeneous disorder with three variants, FHH1 to FHH3. FHH1 is caused by loss-of-function mutations of the calcium-sensing receptor (CaSR), a G-protein coupled receptor that predominantly signals via G-protein subunit alpha-11 (Gα11 ) to regulate calcium homeostasis. FHH2 is the result of loss-of-function mutations in Gα11 , encoded by GNA11, and to date only two FHH2-associated Gα11 missense mutations (Leu135Gln and Ile200del) have been reported.
View Article and Find Full Text PDFThe adaptor protein-2 sigma subunit (AP2σ2) is pivotal for clathrin-mediated endocytosis of plasma membrane constituents such as the calcium-sensing receptor (CaSR). Mutations of the AP2σ2 Arg15 residue result in familial hypocalciuric hypercalcaemia type 3 (FHH3), a disorder of extracellular calcium (Ca(2+) o) homeostasis. To elucidate the role of AP2σ2 in Ca(2+) o regulation, we investigated 65 FHH probands, without other FHH-associated mutations, for AP2σ2 mutations, characterized their functional consequences and investigated the genetic mechanisms leading to FHH3.
View Article and Find Full Text PDFContext: Pituitary adenomas and pheochromocytomas/paragangliomas (pheo/PGL) can occur in the same patient or in the same family. Coexistence of the two diseases could be due to either a common pathogenic mechanism or a coincidence.
Objective: The objective of the investigation was to study the possible coexistence of pituitary adenoma and pheo/PGL.
Succinate Dehydrogenase-B (SDH-B) gene mutations constitute one of the most frequent forms of hereditary paragangliomas (PGL). Genetic study is advised in all cases for the evaluation of tumour behaviour, the selection of optimal management and the surveillance of the first degree relatives. There are limited data on the genetic characteristics of patients with PGLs from Middle East countries, and to our knowledge this is the first study from Iran.
View Article and Find Full Text PDFJ Clin Endocrinol Metab
September 2014
Context: Bilateral macronodular adrenal hyperplasia (BMAH) is a rare form of adrenal Cushing's syndrome. Familial cases have been reported, but at the time we conducted this study, the genetic basis of BMAH was unknown. Recently, germline variants of armadillo repeat containing 5 (ARMC5) in patients with isolated BMAH and somatic, second-hit mutations in tumor nodules, were identified.
View Article and Find Full Text PDFContext: CDC73 mutations frequently underlie the hyperparathyroidism-jaw tumor syndrome, familial isolated hyperparathyroidism (FIHP), and parathyroid carcinoma. It has also been suggested that CDC73 deletion analysis should be performed in those patients without CDC73 mutations.
Objective: To investigate for CDC73 deletion in a family with FIHP previously reported not to have CDC73 mutations.
Context: Autosomal dominant hypocalcemia (ADH) types 1 and 2 are due to calcium-sensing receptor (CASR) and G-protein subunit-α11 (GNA11) gain-of-function mutations, respectively, whereas CASR and GNA11 loss-of-function mutations result in familial hypocalciuric hypercalcemia (FHH) types 1 and 2, respectively. Loss-of-function mutations of adaptor protein-2 sigma subunit (AP2σ 2), encoded by AP2S1, cause FHH3, and we therefore sought for gain-of-function AP2S1 mutations that may cause an additional form of ADH, which we designated ADH3.
Objective: The objective of the study was to investigate the hypothesis that gain-of-function AP2S1 mutations may cause ADH3.
Objective: Multiple endocrine neoplasia 2 (MEN2) is an autosomal dominant disorder characterized by medullary thyroid carcinoma (MTC), pheochromocytoma, and hyperparathyroidism, with mutations at codon 634 in exon 11 of the RET (REarranged during Transfection) proto-oncogene identified as the most common genetic defect.
Methods: We present a patient diagnosed with a left adrenal pheochromocytoma at a young age in whom we identified a mutation at codon 635 of the RET gene. No MTC has been clinically detected during a 6-year follow-up.