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Open access

Syed Ali Imran, Khaled A Aldahmani, Lynette Penney, Sidney E Croul, David B Clarke, David M Collier, Donato Iacovazzo and Márta Korbonits

Summary

Early-onset acromegaly causing gigantism is often associated with aryl-hydrocarbon-interacting receptor protein (AIP) mutation, especially if there is a positive family history. A15y male presented with tiredness and visual problems. He was 201 cm tall with a span of 217 cm. He had typical facial features of acromegaly, elevated IGF-1, secondary hypogonadism and a large macroadenoma. His paternal aunt had a history of acromegaly presenting at the age of 35 years. Following transsphenoidal surgery, his IGF-1 normalized and clinical symptoms improved. He was found to have a novel AIP mutation destroying the stop codon c.991T>C; p.*331R. Unexpectedly, his father and paternal aunt were negative for this mutation while his mother and older sister were unaffected carriers, suggesting that his aunt represents a phenocopy.

Learning points:

  • Typical presentation for a patient with AIP mutation with excess growth and eunuchoid proportions.

  • Unusual, previously not described AIP variant with loss of the stop codon.

  • Phenocopy may occur in families with a disease-causing germline mutation.

Open access

Elena Carrillo, Amparo Lomas, Pedro J Pinés and Cristina Lamas

Summary

Mutations in hepatocyte nuclear factor 1β gene (HNF1B) are responsible for a multisystemic syndrome where monogenic diabetes (classically known as MODY 5) and renal anomalies, mostly cysts, are the most characteristic findings. Urogenital malformations, altered liver function tests, hypomagnesemia or hyperuricemia and gout are also part of the syndrome. Diabetes in these patients usually requires early insulinization. We present the case of a young non-obese male patient with a personal history of renal multicystic dysplasia and a debut of diabetes during adolescence with simple hyperglycemia, negative pancreatic autoimmunity and detectable C-peptide levels. He also presented epididymal and seminal vesicle cysts, hypertransaminasemia, hyperuricemia and low magnesium levels. In the light of these facts we considered the possibility of a HNF1B mutation. The sequencing study of this gene confirmed a heterozygous mutation leading to a truncated and less functional protein. Genetic studies of his relatives were negative; consequently, it was classified as a de novo mutation. In particular, our patient maintained good control of his diabetes on oral antidiabetic agents for a long period of time. He eventually needed insulinization although oral therapy was continued alongside, allowing reduction of prandial insulin requirements. The real prevalence of mutations in HNF1B is probably underestimated owing to a wide phenotypical variability. As endocrinologists, we should consider this possibility in young non-obese diabetic patients with a history of chronic non-diabetic nephropathy, especially in the presence of some of the other characteristic manifestations.

Learning points:

  • HNF1B mutations are a rare cause of monogenic diabetes, often being a part of a multisystemic syndrome.

  • The combination of young-onset diabetes and genitourinary anomalies with slowly progressive nephropathy of non-diabetic origin in non-obese subjects should rise the suspicion of such occurrence. A family history may not be present.

  • Once diagnosis is made, treatment of diabetes with oral agents is worth trying, since the response can be sustained for a longer period than the one usually described. Oral treatment can help postpone insulinization and, once this is necessary, can help reduce the required doses.

Open access

Bronwen E Warner, Carol D Inward and Christine P Burren

Summary

This case, presenting with bilateral impalpable testes, illustrates the relevance of a broad differential disorders of sex development case management. It provides new insights on hypothalamic–pituitary–gonadal (HPG) axis and testicular function abnormalities in the multisystem disorder of Lowe syndrome. Lowe syndrome, also known as oculocerebrorenal syndrome, is a rare disorder characterised by eye abnormalities, central nervous system involvement and proximal renal tubular acidosis. There are a handful of reports of pubertal delay, infertility and cryptorchidism in Lowe syndrome. Biochemistry aged 72 h: testosterone 6.4 nmol/L, LH <0.5 IU/L and FSH <0.5 IU/L. Gonadotropin-releasing hormone stimulation test identified significantly raised baseline LH = 45.4 IU/L (contrasts with earlier undetectable LH), with a 20% increase on stimulation, while baseline FSH = 4.3 IU/L with no increase on stimulation. Day 14 HCG stimulation test produced an acceptable 50% increase in testosterone. The constellation of further abnormalities suggested Lowe syndrome: hypotonia, bilateral cataracts (surgical extraction and intraocular lens implantation) and renal tubular acidosis (microscopic haematuria, hypercalciuria, proteinuria, generalised aminoaciduria, hypophosphataemia and metabolic acidosis). DNA sequencing identified de novo hemizygous frameshift mutation OCRL c.2409_2410delCT in exon 22. Interpretation of initial and repeat GnRH and HCG testing indicates the likelihood of testicular failure. Partial testicular descent occurred but left orchidopexy was required. Improving long-term gonadal function in Lowe syndrome assumes increased importance for current cohorts as advances in renal replacement therapy have greatly improved life expectancy. Noting HPG axis abnormalities in Lowe syndrome in infancy can identify cases requiring increased surveillance of pubertal progress for earlier detection and management.

Learning points:

  • Clinical endocrine problems in Lowe syndrome has been reported, but has focused on abnormalities in adolescence and young adulthood: pubertal delay and infertility.

  • We present an infant with isolated LH elevation at baseline and on GnRH stimulation testing who also had bilateral impalpable testes.

  • Early testing of the HPG axis in patients with Lowe syndrome may help predict gonadal abnormalities from a younger age, which will enhance the overall case management into adolescence.

Open access

Kohei Saitoh, Takako Yonemoto, Takeshi Usui, Kazuhiro Takekoshi, Makoto Suzuki, Yoshiharu Nakashima, Koji Yoshimura, Rieko Kosugi, Tatsuo Ogawa and Tatsuhide Inoue

Summary

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare tumours with a heterogeneous genetic background. Up to 40% of apparently sporadic PCC/PGL cases carry 1 of the 12 gene germline mutations conferring genetic susceptibility to PCC/PGL. Although the precise mechanisms are unclear, TMEM127 is one of the rare responsible genes for PCC/PGL. Here we report the case of a patient with familial PCC having a novel TMEM127 variant (c.119C > T, p.S40F). In silico prediction analysis to evaluate the functional significance of this variant suggested that it is a disease-causing variant. A PCC on the left side was considered to be the dominant lesion, and unilateral adrenalectomy was performed. The histopathologic findings were consistent with benign PCC. A loss of heterogeneity of the TMEM127 variant was detected in the surgically removed tumour.

Learning points:

  • c.119C > T (p.S40F) is a novel TMEM127 variant that can cause pheochromocytoma.

  • The tumour showed loss of heterozygosity of this TMEM127 variant.

  • The clinical phenotype of this mutation is putative bilateral pheochromocytoma in the 4th decade.

  • Unilateral adrenalectomy may be performed as the initial surgery in such cases.

Open access

Teresa Rego, Fernando Fonseca, Stéphanie Espiard, Karine Perlemoine, Jérôme Bertherat and Ana Agapito

Summary

PBMAH is a rare etiology of Cushing syndrome (CS). Familial clustering suggested a genetic cause that was recently confirmed, after identification of inactivating germline mutations in armadillo repeat-containing 5 (ARMC5) gene. A 70-year-old female patient was admitted due to left femoral neck fracture in May 2014, in Orthopedics Department. During hospitalization, hypertension (HTA) and hypokalemia were diagnosed. She presented with clinical signs of hypercortisolism and was transferred to the Endocrinology ward for suspected CS. Laboratory workup revealed: ACTH <5 pg/mL; urinary free cortisol (UFC), 532 µg/24 h (normal range: 20–90); failure to suppress the low-dose dexamethasone test (0.5 mg every 6 h for 48 h): cortisol 21 µg/dL. Abdominal magnetic resonance imaging (MRI) showed enlarged nodular adrenals (right, 55 × 54 × 30 mm; left, 85 × 53 × 35 mm), and she was submitted to bilateral adrenalectomy. In 2006, this patient’s 39-year-old daughter had been treated by one of the authors. She presented with severe clinical and biological hypercortisolism. Computed tomography (CT) scan showed massively enlarged nodular adrenals with maximal axis of 15 cm for both. Bilateral adrenalectomy was performed. In this familial context of PBMAH, genetic study was performed. Leucocyte DNA genotyping identified in both patients the same germline heterozygous ARMC5 mutation in exon 1 c.172_173insA p.I58Nfs*45. The clinical cases herein described have an identical phenotype with severe hypercortisolism and huge adrenal glands, but different ages at the time of diagnosis. Current knowledge of inheritance of this disease, its insidious nature and the well-known deleterious effect of hypercortisolism favor genetic study to timely identify and treat these patients.

Learning points:

  • PBMAH is a rare etiology of CS, characterized by functioning adrenal macronodules and variable cortisol secretion.

  • The asymmetric/asynchronous involvement of only one adrenal gland can also occur, making disease diagnosis a challenge.

  • Familial clustering suggests a genetic cause that was recently confirmed, after identification of inactivating germline mutations in armadillo repeat-containing 5 (ARMC5) gene.

  • The insidious nature of this disease and the well-known deleterious effect of hypercortisolism favor genetic study of other family members, to diagnose and treat these patients timely.

  • As ARMC5 is expressed in many organs and recent findings suggest an association of PBMAH and meningioma, a watchful follow-up is required.

Open access

Whitney L Stuard, Bryan K Gallerson and Danielle M Robertson

Summary

The use of in vivo confocal microscopy (IVCM) is rapidly emerging as an important clinical tool to evaluate changes in corneal sensory nerves as a surrogate measure for diabetic peripheral neuropathy. Commonly used metrics to document and grade the severity of diabetes and risk for diabetic peripheral neuropathy include nerve fiber length, density, branching and tortuosity. In addition to corneal nerves, thinning of the retinal fiber layer has been shown to correlate with the severity of diabetic disease. Here, we present a case report on a pre-diabetic 60-year-old native American woman with abnormal corneal nerve morphology and retinal nerve fiber layer thinning. Her past medical history was positive for illicit substance abuse. IVCM showed a decrease in nerve fiber density and length, in addition to abnormally high levels of tortuosity. OCT revealed focal areas of reduced retinal nerve fiber layer thickness that were asymmetric between eyes. This is the first report of abnormally high levels of tortuosity in the corneal sub-basal nerve plexus in a patient with a past history of cocaine abuse. It also demonstrates, for the first time, that illicit substance abuse can have long-term adverse effects on ocular nerves for years following discontinued use of the drug. Studies using IVCM to evaluate changes in corneal nerve morphology in patients with diabetes need to consider a past history of illicit drug use as an exclusionary measure.

Learning points:

  • Multiple ocular and systemic factors can impede accurate assessment of the corneal sub-basal nerve plexus by IVCM in diabetes.

  • Although current history was negative for illicit substance abuse, past history can have longstanding effects on corneal nerves and the retinal nerve fiber layer.

  • Illicit drug use must be considered an exclusionary measure when evaluating diabetes-induced changes in corneal nerve morphology and the retinal nerve fiber layer.

Open access

María Clemente, Alejandro Vargas, Gema Ariceta, Rosa Martínez, Ariadna Campos and Diego Yeste

Summary

HNF4A gene mutations have been reported in cases of transient and persistent hyperinsulinaemic hypoglycaemia of infancy (HHI), particularly in families with adulthood diabetes. The case of a patient with HHI, liver impairment and renal tubulopathy due to a mutation in HNF4A is reported.

Learning points:

  • Urine specimen study in cases of HHI with diazoxide response is necessary to rule out specific metabolic conditions (l-3-hydroxyacyl-coenzyme A dehydrogenase deficiency) or tubular renal involvement.

  • Hyperinsulinaemic hypoglycaemia due to the heterozygous mutation (p.Arg63Trp, c. 187C > T) in the HNF4A gene is associated with renal tubulopathy and liver involvement.

  • Follow-up of patients diagnosed of HHI is mandatory to detect associated conditions.

Open access

Anil Piya, Jasmeet Kaur, Alan M Rice and Himangshu S Bose

Summary

Cholesterol transport into the mitochondria is required for synthesis of the first steroid, pregnenolone. Cholesterol is transported by the steroidogenic acute regulatory protein (STAR), which acts at the outer mitochondrial membrane prior to its import. Mutations in the STAR protein result in lipoid congenital adrenal hyperplasia (CAH). Although the STAR protein consists of seven exons, biochemical analysis in nonsteroidogenic COS-1 cells showed that the first two were not essential for pregnenolone synthesis. Here, we present a patient with ambiguous genitalia, salt-lossing crisis within two weeks after birth and low cortisol levels. Sequence analysis of the STAR, including the exon–intron boundaries, showed the complete deletion of exon 1 as well as more than 50 nucleotides upstream of STAR promoter. Mitochondrial protein import with the translated protein through synthesis cassette of the mutant STAR lacking exon 1 showed protein translation, but it is less likely to have synthesized without a promoter in our patient. Thus, a full-length STAR gene is necessary for physiological mitochondrial cholesterol transport in vivo.

Learning points:

  • STAR exon 1 deletion caused lipoid CAH.

  • Exon 1 substitution does not affect biochemical activity.

  • StAR promoter is responsible for gonadal development.

Open access

Liudmila Rozhinskaya, Ekaterina Pigarova, Ekaterina Sabanova, Elizaveta Mamedova, Iya Voronkova, Julia Krupinova, Larisa Dzeranova, Anatoly Tiulpakov, Vera Gorbunova, Nadezhda Orel, Artur Zalian, Galina Melnichenko and Ivan Dedov

Summary

Parathyroid carcinoma is an extremely rare disorder with little treatment options. It could be misdiagnosed in medical centers with little experience in management of such cases. Our clinical case shows that the initial misdiagnosis of a parathyroid carcinoma in a young woman has led to the development of multiple lung metastases, thus making its treatment hardly possible. Initiation of treatment with sorafenib – a multi-kinase inhibitor approved for treatment of different types of cancer but not parathyroid carcinoma – has led to a significant decrease in the size of lung metastases and has prevented the progression of hyperparathyroidism, which is usually severe in cases of parathyroid carcinoma. The detection of a germline CDC73 mutation in this patient has raised additional concerns about the necessity of periodic screening for early detection of renal, jaw and uterine lesions.

Learning points:

  • Diagnosis of parathyroid carcinoma may be challenging due to the absence of reliable diagnostic criteria. Thus, thorough histological examination is needed using immunohistochemical staining of resected tissue in suspicious cases.

  • CDC73 genetic testing should be considered in patients with parathyroid carcinoma.

  • Sorafenib may be a promising treatment of patients with parathyroid carcinoma with distant metastases.

Open access

Rowena Speak, Jackie Cook, Barney Harrison and John Newell-Price

Mutations of the rearranged during transfection (RET) proto-oncogene, located on chromosome 10q11.2, cause multiple endocrine neoplasia type 2A (MEN2A). Patients with mutations at the codon 609 usually exhibit a high penetrance of medullary thyroid cancer (MTC), but a sufficiently low penetrance of phaeochromocytoma that screening for this latter complication has been called to question. Patients with other RET mutations are at higher risk of younger age onset phaeochromocytoma if they also possess other RET polymorphisms (L769L, S836S, G691S and S904S), but there are no similar data for patients with 609 mutations. We investigated the unusual phenotypic presentation in a family with MEN2A due to a C609Y mutation in RET. Sanger sequencing of the entire RET-coding region and exon–intron boundaries was performed. Five family members were C609Y mutation positive: 3/5 initially presented with phaeochromocytoma, but only 1/5 had MTC. The index case aged 73 years had no evidence of MTC, but presented with phaeochromocytoma. Family members also possessed the G691S and S904S RET polymorphisms. We illustrate a high penetrance of phaeochromocytoma and low penetrance of MTC in patients with a RET C609Y mutation and polymorphisms G691S and S904S. These data highlight the need for life-long screening for the complications of MEN2A in these patients and support the role for the screening of RET polymorphisms for the purposes of risk stratification.

Learning points:

  • C609Y RET mutations may be associated with a life-long risk of phaeochromocytoma indicating the importance of life-long screening for this condition in patients with MEN2A.

  • C609Y RET mutations may be associated with a lower risk of MTC than often quoted, questioning the need for early prophylactic thyroid surgery discussion at the age of 5 years.

  • There may be a role for the routine screening of RET polymorphisms, and this is greatly facilitated by the increasing ease of access to next-generation sequencing.