[show abstract][hide abstract] ABSTRACT: We report on an adult woman with rare coexistence of acromegaly, pheochromocytoma (PHEO), gastrointestinal stromal tumor (GIST), intestinal polyposis, and thyroid follicular adenoma. At the age of 56, she was diagnosed with acromegaly caused by a pituitary macroadenoma, treated by transsphenoidal surgery, radiotherapy, and octreotide. During routine colonoscopy, multiple polyps were identified as tubular adenomas with high-grade dysplasia on histology. Years later, an abdominal mass of 8.0 x 6.2 cm was detected by routine ultrasound. Surgical exploration revealed an adrenal mass and another tumor adhered to the lesser gastric curvature, which were removed. Pathology confirmed the diagnosis of PHEO and GIST. PHEO immunohistochemistry was negative for GHRH. During follow-up, nodular goiter was found with normal levels of calcitonin and inconclusive cytology. Near-total thyroidectomy was performed, revealing a follicular adenoma. Her family history was negative for all of these tumor types. Genetic analysis for PHEO/paraganglioma genes (SDH A-D, SDHAF2, RET, VHL, TMEM127, and MAX), and pituitary-related genes (AIP, MEN1, and p27) were negative. Though the finding of PHEO and acromegaly with multiple other tumors could be a fortuitous coexistence, we suggest that this case may represent a new variant of MEN syndrome with a de novo germline mutation in a not yet identified gene. Arq Bras Endocrinol Metab. 2012;56(8):507-12.
Arquivos brasileiros de endocrinologia e metabologia 11/2012; 56(8):507-12. · 0.68 Impact Factor
[show abstract][hide abstract] ABSTRACT: Familial isolated pituitary adenoma (FIPA), defined as the occurrence of at least two cases of pituitary adenoma in a family that does not exhibit features of syndromic diseases, such as Carney complex or Multiple Endocrine Neoplasia type 1 or 4, is a rare autosomal dominant disease with low penetrance. About 20 % of the families with FIPA harbor inactivating mutation in aryl hydrocarbon receptor-interacting protein gene (AIP) associated with loss of heterozygosity of the same genetic locus (11q13) in the tumor. Rarely different types of extra-pituitary tumors have been described in the setting of AIP mutation-positive FIPA. We present the case of a patient who was diagnosed with acromegaly due to the AIP mutation c.241C>T (p.R81X) at the age of 34 years, and treated by transsphenoidal surgery. At the age of 43 years she was diagnosed with a meningioma, and at age 46 had recurrence of the somatotropinoma. Genetic studies demonstrated loss of the normal allele (by sequencing and microsatellite analysis) in DNA from the pituitary adenoma but not from the meningioma, suggesting a selective involvement of AIP mutation in the pathogenesis of the pituitary adenoma, and a casual association with the meningioma. Further investigations are required to define the exact role of AIP in non-pituitary tumorigenesis.
[show abstract][hide abstract] ABSTRACT: Alagille syndrome is a multisystem disorder characterized by highly variable expressivity, most frequently caused by heterozygous JAG1 gene mutations. Classic diagnostic criteria combine the presence of bile duct paucity on liver biopsy with three of five systems affected; liver, heart, skeleton, eye and dysmorphic facies. The aim of this study was to determine the prevalence and distribution of JAG1 mutations in patients referred for routine clinical diagnostic testing. Clinical data were available for 241 patients from 135 families. The index cases were grouped according to the number of systems affected (heart, liver, skeletal, eye and facies) and the mutation frequency calculated for each group. JAG1 mutations were identified in 59/135 (44%) probands. The highest mutation detection rates were observed in patients with the most frequent presenting features of Alagille syndrome; ranging from 20% (one system) to 86% (five systems). The overall mutation pick-up rate in a clinical diagnostic setting was lower than in previous research studies. Identification of a JAG1 gene mutation is particularly useful for those patients with atypical or mild Alagille syndrome who do not meet classic diagnostic criteria as it provides a definite molecular diagnosis and allows accurate genetic counselling for the family.
[show abstract][hide abstract] ABSTRACT: Gigantism results when a growth hormone-secreting pituitary adenoma is present before epiphyseal fusion. In 1909, when Harvey Cushing examined the skeleton of an Irish patient who lived from 1761 to 1783, he noted an enlarged pituitary fossa. We extracted DNA from the patient's teeth and identified a germline mutation in the aryl hydrocarbon-interacting protein gene (AIP). Four contemporary Northern Irish families who presented with gigantism, acromegaly, or prolactinoma have the same mutation and haplotype associated with the mutated gene. Using coalescent theory, we infer that these persons share a common ancestor who lived about 57 to 66 generations earlier.
New England Journal of Medicine 01/2011; 364(1):43-50. · 51.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: Familial isolated pituitary adenoma (FIPA) is an autosomal dominant condition with variable genetic background and incomplete penetrance. Germline mutations of the aryl hydrocarbon receptor interacting protein (AIP) gene have been reported in 15-40% of FIPA patients. Limited data are available on the functional consequences of the mutations or regarding the regulation of the AIP gene. We describe a large cohort of FIPA families and characterize missense and silent mutations using minigene constructs, luciferase and beta-galactosidase assays, as well as in silico predictions. Patients with AIP mutations had a lower mean age at diagnosis (23.6+/-11.2 years) than AIP mutation-negative patients (40.4+/-14.5 years). A promoter mutation showed reduced in vitro activity corresponding to lower mRNA expression in patient samples. Stimulation of the protein kinase A-pathway positively regulates the AIP promoter. Silent mutations led to abnormal splicing resulting in truncated protein or reduced AIP expression. A two-hybrid assay of protein-protein interaction of all missense variants showed variable disruption of AIP-phosphodiesterase-4A5 binding. In summary, exonic, promoter, splice-site, and large deletion mutations in AIP are implicated in 31% of families in our FIPA cohort. Functional characterization of AIP changes is important to identify the functional impact of gene sequence variants.
Human Mutation 08/2010; 31(8):950-60. · 5.21 Impact Factor
[show abstract][hide abstract] ABSTRACT: Hepatocyte nuclear factor-1beta (HNF-1beta) is a critical transcription factor in pancreatic and renal development. Our previous report identified HNF-1beta mutations in 23/160 patients with unexplained renal disease. The most common phenotype is renal cysts, which is frequently associated with early-onset diabetes in the renal cysts and diabetes (RCAD) syndrome. HNF-1beta gene deletions have recently been shown to cause renal malformations and early-onset diabetes.
We developed a multiplex ligation-dependent probe amplification (MLPA) assay for HNF-1beta gene dosage analysis and tested patients with unexplained renal disease in whom mutations had not been found by sequencing.
Whole HNF-1beta gene deletions were detected in 15/133 probands. Renal cysts were present in 13/15, including three with glomerulocystic kidney disease and one with cystic renal dysplasia. Renal function ranged from normal to transplantation aged 3 years. Ten probands had diabetes (nine having RCAD). In addition, four had abnormal liver function tests, two showed pancreatic atrophy and 3/10 female probands had uterine malformations. Whole HNF-1beta gene deletions are a common cause of developmental renal disease, particularly renal cystic disease with or without diabetes.
The phenotype associated with deletions or coding region/splicing mutations is very similar suggesting that haploinsufficiency is the underlying mechanism. Patients with features suggestive of the HNF-1beta clinical phenotype should be tested for mutations both by sequence and dosage analysis.
[show abstract][hide abstract] ABSTRACT: Macrosomia is associated with considerable neonatal and maternal morbidity. Factors that predict macrosomia are poorly understood. The increased rate of macrosomia in the offspring of pregnant women with diabetes and in congenital hyperinsulinaemia is mediated by increased foetal insulin secretion. We assessed the in utero and neonatal role of two key regulators of pancreatic insulin secretion by studying birthweight and the incidence of neonatal hypoglycaemia in patients with heterozygous mutations in the maturity-onset diabetes of the young (MODY) genes HNF4A (encoding HNF-4alpha) and HNF1A/TCF1 (encoding HNF-1alpha), and the effect of pancreatic deletion of Hnf4a on foetal and neonatal insulin secretion in mice.
We examined birthweight and hypoglycaemia in 108 patients from families with diabetes due to HNF4A mutations, and 134 patients from families with HNF1A mutations. Birthweight was increased by a median of 790 g in HNF4A-mutation carriers compared to non-mutation family members (p < 0.001); 56% (30/54) of HNF4A-mutation carriers were macrosomic compared with 13% (7/54) of non-mutation family members (p < 0.001). Transient hypoglycaemia was reported in 8/54 infants with heterozygous HNF4A mutations, but was reported in none of 54 non-mutation carriers (p = 0.003). There was documented hyperinsulinaemia in three cases. Birthweight and prevalence of neonatal hypoglycaemia were not increased in HNF1A-mutation carriers. Mice with pancreatic beta-cell deletion of Hnf4a had hyperinsulinaemia in utero and hyperinsulinaemic hypoglycaemia at birth.
HNF4A mutations are associated with a considerable increase in birthweight and macrosomia, and are a novel cause of neonatal hypoglycaemia. This study establishes a key role for HNF4A in determining foetal birthweight, and uncovers an unanticipated feature of the natural history of HNF4A-deficient diabetes, with hyperinsulinaemia at birth evolving to decreased insulin secretion and diabetes later in life.
PLoS Medicine 04/2007; 4(4):e118. · 15.25 Impact Factor