The molecular landscape of osteogenesis imperfecta in a Brazilian tertiary service cohort.

We have sought the molecular diagnosis of OI in 38 Brazilian cases through targeted sequencing of 15 candidate genes. While 71% had type 1 collagen-related OI, defects in FKBP10, PLOD2 and SERPINF1, and a potential digenic P3H1/WNT1 interaction were prominent causes of OI in this underrepresented population. INTRODUCTION: Defects in type 1 collagen reportedly account for 85-90% of osteogenesis imperfecta (OI) cases, but most available molecular data has derived from Sanger sequencing-based approaches in developed countries. Massively parallel sequencing (MPS) allows for systematic and comprehensive analysis of OI genes simultaneously. Our objective was to obtain the molecular diagnosis of OI in a single Brazilian tertiary center cohort. METHODS: Forty-nine individuals (84% adults) with a clinical diagnosis of OI, corresponding to 30 sporadic and 8 familial cases, were studied. Sixty-three percent had moderate to severe OI, and consanguinity was common (26%). Coding regions and 25-bp boundaries of 15 OI genes (COL1A1, COL1A2, IFITM5 [plus 5'UTR], SERPINF1, CRTAP, P3H1, PPIB, SERPINH1, FKBP10, PLOD2, BMP1, SP7, TMEM38B, WNT1, CREB3L1) were analyzed by targeted MPS and variants of interest were confirmed by Sanger sequencing or SNP array. RESULTS: A molecular diagnosis was obtained in 97% of cases. COL1A1/COL1A2 variants were identified in 71%, whereas 26% had variants in other genes, predominantly FKBP10, PLOD2, and SERPINF1. A potential digenic interaction involving P3H1 and WNT1 was identified in one case. Phenotypic variability with collagen defects could not be explained by evident modifying variants. Four consanguineous cases were associated to heterozygous COL1A1/COL1A2 variants, and two nonconsanguineous cases had compound PLOD2 heterozygosity. CONCLUSIONS: Novel disease-causing variants were identified in 29%, and a higher proportion of non-collagen defects was seen. Obtaining a precise diagnosis of OI in underrepresented populations allows expanding our understanding of its molecular landscape, potentially leading to improved personalized care in the future.

Value of insoluble PABPN1 accumulation in the diagnosis of oculopharyngeal muscular dystrophy.

BACKGROUND AND PURPOSE: The aim was to assess the value of insoluble PABPN1 muscle fibre nuclei accumulation in the diagnosis of atypical cases of oculopharyngeal muscular dystrophy (OPMD). METHODS: Muscle biopsies from a selected cohort of 423 adult patients from several Italian neuromuscular centres were analysed by immunofluorescence: 30 muscle biopsies of genetically proven OPMD, 30 biopsies from patients not affected by neuromuscular disorders, 220 from genetically undiagnosed patients presenting ptosis or swallowing disturbances, progressive lower proximal weakness and/or isolated rimmed vacuoles at muscle biopsy and 143 muscle biopsies of patients affected by other neuromuscular diseases. RESULTS: The detection of insoluble nuclear PABPN1 accumulation is rapid, sensitive (100%) and specific (96%). The revision of our cohort allowed us to discover 23 new OPMD cases out of 220 patients affected with nonspecific muscle diseases. CONCLUSIONS: Oculopharyngeal muscular dystrophy is often misdiagnosed leading to diagnosis delay, causing waste of time and resources. A great number of these cases present symptoms and histological findings frequently overlapping with other muscle diseases, i.e. inclusion body myositis and progressive external ophthalmoplegia. PABPN1 nuclear accumulation is a reliable method for diagnostic purposes and it is safe and useful in helping pathologists and clinicians to direct genetic analysis in the case of suspected OPMD, even when clinical and histological clues are deceptive.

Identification of the first homozygous 1-bp deletion in GDF9 gene leading to primary ovarian insufficiency by using targeted massively parallel sequencing.

Targeted massively parallel sequencing (TMPS) has been used in genetic diagnosis for Mendelian disorders. In the past few years, the TMPS has identified new and already described genes associated with primary ovarian insufficiency (POI) phenotype. Here, we performed a targeted gene sequencing to find a genetic diagnosis in idiopathic cases of Brazilian POI cohort. A custom SureSelectXT DNA target enrichment panel was designed and the sequencing was performed on Illumina NextSeq sequencer. We identified 1 homozygous 1-bp deletion variant (c.783delC) in the GDF9 gene in 1 patient with POI. The variant was confirmed and segregated using Sanger sequencing. The c.783delC GDF9 variant changed an amino acid creating a premature termination codon (p.Ser262Hisfs*2). This variant was not present in all public databases (ExAC/gnomAD, NHLBI/EVS and 1000Genomes). Moreover, it was absent in 400 alleles from fertile Brazilian women screened by Sanger sequencing. The patient's mother and her unaffected sister carried the c.783delC variant in a heterozygous state, as expected for an autosomal recessive inheritance. Here, the TMPS identified the first homozygous 1-bp deletion variant in GDF9. This finding reveals a novel inheritance pattern of pathogenic variant in GDF9 associated with POI, thus improving the genetic diagnosis of this disorder.

PDX1 -MODY and dorsal pancreatic agenesis: New phenotype of a rare disease.

Maturity-Onset Diabetes of the Young (MODY) type 4 or PDX1 -MODY is a rare form of monogenic diabetes caused by heterozygous variants in PDX1 . Pancreatic developmental anomalies related to PDX1 are reported only in neonatal diabetes cases. Here, we describe dorsal pancreatic agenesis in 2 patients with PDX1 -MODY. The proband presented with diabetes since 14 years of age and maintained regular glycemic control with low doses of basal insulin and detectable C-peptide levels after 38 years with diabetes. A diagnosis of MODY was suspected. Targeted next-generation sequencing identified a heterozygous variant in PDX1 : c.188delC/p.Pro63Argfs*60. Computed tomography revealed caudal pancreatic agenesis. Low fecal elastase indicated exocrine insufficiency. His son had impaired glucose tolerance, presented similar pancreatic agenesis, and harbored the same allelic variant. The unusual presentation in this Brazilian family enabled expansion upon a rare disease phenotype, demonstrating the possibility of detecting pancreatic malformation even in cases of PDX1 -related diabetes diagnosed after the first year of life. This finding can improve the management of MODY4 patients, leading to precocious investigation of pancreatic dysgenesis and exocrine dysfunction.

DAX1 Overexpression in Pediatric Adrenocortical Tumors: A Synergic Role with SF1 in Tumorigenesis.

DAX1 transcription factor is a key determinant of adrenogonadal development, acting as a repressor of SF1 targets in steroidogenesis. It was recently demonstrated that DAX1 regulates pluripotency and differentiation in murine embryonic stem cells. In this study, we investigated DAX1 expression in adrenocortical tumors (ACTs) and correlated it with SF1 expression and clinical parameters. DAX1 and SF1 protein expression were assessed in 104 ACTs from 34 children (25 clinically benign and 9 malignant) and 70 adults (40 adenomas and 30 carcinomas). DAX1 gene expression was studied in 49 ACTs by quantitative real-time PCR. A strong DAX1 protein expression was demonstrated in 74% (25 out of 34) and 24% (17 out of 70) of pediatric and adult ACTs, respectively (χ(2)=10.1, p=0.002). In the pediatric group, ACTs with a strong DAX1 expression were diagnosed at earlier ages than ACTs with weak expression [median 1.2 (range, 0.5-4.5) vs. 2.2 (0.9-9.4), p=0.038]. DAX1 expression was not associated with functional status in ACTs. Interestingly, a positive correlation was observed between DAX1 and SF1 protein expression in both pediatric and adult ACTs (r=0.55 for each group separately; p<0.0001). In addition, DAX1 gene expression was significantly correlated with SF1 gene expression (p<0.0001, r=0.54). In conclusion, DAX1 strong protein expression was more frequent in pediatric than in adult ACTs. Additionally, DAX1 and SF1 expression positively correlated in ACTs, suggesting that these transcription factors might cooperate in adrenocortical tumorigenesis.

Relationship between glycemic control and coronary artery disease severity, prevalence and plaque characteristics by computed tomography coronary angiography in asymptomatic type 2 diabetic patients.

Evaluate whether glycemic control in type 2 diabetes (DM2) asymptomatic for coronary artery disease (CAD) affects not only the presence and magnitude of CAD but also the characteristics of plaque vulnerability using multidetector row computed coronary tomography (MDCT). Acute coronary syndrome (ACS) is frequently observed in asymptomatic DM2 patients. Positive vessel remodeling (PR) and low-attenuation plaques (LAP) identified by MDCT have been demonstrated to be characteristics of subsequent culprit lesions of ACS. However, little is known regarding plaque characteristics in asymptomatic diabetic patients and their relationship with glycemic control. Ninety asymptomatic DM2 patients, aged 40-65 years old, underwent MDCT. The presence of atherosclerotic obstruction, defined as coronary stenosis ≥50 %, and plaque characteristics were compared between two groups of patients with A1c < 7 and A1c ≥ 7 %. Of the 90 patients, 38 (42.2 %) presented with coronary atherosclerotic plaques, 11 had A1c < 7 % and 27 had A1c ≥ 7 % (p = 0.0006). Fourteen patients had significant lumen obstruction higher than 50 %: 3 in the A1c < 7 % group and 11 in the A1c ≥ 7 % group (p = 0.02). Non-calcified plaque was more prevalent in the A1c ≥ 7 % group (p = 0.005). In eleven patients, the simultaneous presence of two vulnerability plaque characteristics (PR and LAP) were observed more frequently in the A1c ≥ 7 group (n = 8) than in the A1c < 7 group (n = 3) (p = 0.04). Asymptomatic DM2 patients with A1c ≥ 7 % have a higher frequency of CAD and a higher proportion of vulnerable atherosclerotic coronary plaque by MDCT compared to patients with DM2 with A1c < 7 in our study.

Sequential studies of glucose tolerance and red blood cell insulin receptors in normal human pregnancy.

Insulin binding to erythrocytes was sequentially studied in 12 healthy pregnant women during the anabolic (11-22 wk) and the catabolic (31-38 wk) gestational phases. For comparison, we studied 12 nonpregnant subjects at mid-luteal and mid-follicular menstrual phases. Oral glucose tolerance tests were also performed during these studies. There was a progressive worsening of the glucose tolerance from the anabolic to the catabolic phase associated with fasting hypoglycemia and hyperinsulinemia. The worsening of glucose tolerance was accompanied by a progressive increment of insulin secretion. Insulin binding to red blood cells increased progressively from the anabolic to the catabolic phase, due to an increased number of receptors per cell, associated with a reduction in the apparent affinity at the low occupancy levels. We concluded that the insulin resistance of pregnancy was not accompanied by an impaired binding of insulin to its receptors, at least in the RBC. The data suggest that the defect of insulin action lies at a site distal to the receptor.

Insulin resistance in Cushing's disease. Evaluation by studies of insulin binding to erythrocytes.

Studies of 125I -insulin binding to erythrocytes (RBC) from 5 patients with Cushing's disease were performed in an attempt to evaluate the insulin resistance in this disease. Five obese, nondiabetic patients and six normal subjects served as controls. Insulin resistance was present in both the obese, nondiabetic subjects and in the patients with Cushing's disease. Patients with Cushing's disease showed insulin resistance out of proportion to obesity, and of greater severity than in the obese subjects. As in previous studies, the insulin resistance of the obese subjects could be at least partially ascribed to a reduced number of receptors. In contrast, in our patients with Cushing's disease, no physiologically significant changes in the parameters of insulin-receptor interaction could be demonstrated. This suggests that the RBC insulin receptor is not involved in this type of insulin resistance.

Radiographic Characteristics of Adrenal Masses Preceding the Diagnosis of Adrenocortical Cancer.

Incidentally discovered adrenal masses are common and the clinical evaluation and surveillance aims to diagnose hormone excess and malignancy. Adrenocortical cancer (ACC) is a very rare malignancy. This study aims to define the imaging characteristics of adrenal tumors preceding the diagnosis of ACC. Patients with prior (>5 months) adrenal tumors (<6 cm) subsequently diagnosed with ACC were identified in a large registry at a tertiary referral center. Retrospective chart and image review for patient characteristics and initial, interval, and diagnostic imaging characteristics (size, homogeneity, borders, density, growth rate, etc.) was conducted. Twenty patients with a diagnosis of ACC and a prior adrenal tumor were identified among 422 patients with ACC. Of these, 17 patients were initially imaged with CT and 3 with MR. Only 2 of the 20 patients had initial imaging characteristics suggestive of a benign lesion. Of initial tumors, 25% were <2 cm in size. Surveillance led to the diagnosis of ACC within 24 months in 50% of patients. The growth pattern was variable with some lesions showing long-term stability (up to 8 years) in size. In conclusion, antecedent lesions in patients with a diagnosis of ACC are often indeterminate by imaging criteria and can be small. Surveillance over 2 years detected only 50% of ACCs. Current practice and guidelines are insufficient in diagnosing ACCs. Given the rarity of ACC, the increased risk and health care costs of additional evaluation may not be warranted.

New evidence for an acute role of protein kinase in hCG action.

The present experiments were designed to study whether exogenous hCG could elicit acute changes in the ovarian concentration of soluble cAMP-dependent protein kinases temporally related to binding of hCG and intracellular accumulation of cAMP. Cyclic AMP dependent protein kinase activity decreased five-fold within 5 to 30 min after intravenous administration of highly purified hCG to pseudopregnant rats. Moreover cAMP dependent protein kinase activity was totally suppressed with 0.5 IU hCG, whereas tissue concentration of cAMP continued to increase throughout the dose range (0.05-5.0 IU) of hCG used in the present studies. A marked fall in cAMP-dependent protein kinase activity had occurred before there was a significant change in intracellular accumulation of cAMP, possibly reflecting intracellular compartmentalization of cAMP. Inhibitors of protein did not affect the hCG-induced changes in tissue concentrations of cAMP and soluble cAMP dependent protein kinase activity but did suppress the recovery of cAMP dependent protein kinase activity to pretreatment levels. Cyclic AMP dependent protein kinases appear to play a significant role in mediating hormonal action in vivo. In addition the present studies suggest that, protein kinases may protect the cell from excessive hormonal stimulation.

Estimation of body fat and lean tissue distribution by dual energy X-ray absorptiometry and abdominal body fat evaluation by computed tomography in Cushing's disease.

Body composition determined by dual energy x-ray absorptiometry and the abdominal visceral fat component determined by computed tomographic scanning were examined in women with Cushing's disease and compared with those in obese women with the same anthropometric parameters and those in nonobese women. Patients with Cushing's had no increase in total body fat or the trunk region (android) component, but had a higher intraabdominal fat area compared to the obese subjects. The total lean tissue mass was slightly reduced in Cushing's compared to that in the obese subjects due to a significant decrease in the muscle of the legs and arms; the reduced amounts of fat and lean tissue masses in the arms were the most significant findings in hypercortisolism. The body mineral and bone calcium contents were slightly reduced in Cushing's compared to those in the obese controls. Thus, although obese subjects had more fat and lean tissue and mineral masses than their normal weight counterparts, the Cushing's patients, with the same total fat mass and its components (except in the arms) as obese individuals, present total lean tissue and fractions, including body mineral and bone calcium contents, similar to those in nonobese subjects due to the depletion of the protein depots, as seen in hypercortisolism.

Preparation of iodine-125-labeled insulin for radioimmunoassay: comparison of lactoperoxidase and chloramine-T iodination.

The enzymatic radioiodination of porcine insulin by a system consisting of lactoperoxidase, hydrogen peroxide, and Na125I was compared with a modified chloramine-T technique. Satisfactory specific activity of the labeled hormone was obtained with the enzymatic iodination, with much greater immunoreactivity and stability than after chloramine-T, besides being quite suitable for the measurement of low plasma insulin levels. There was a positive and highly significant correlation between the insulin concentrations measured with the two tracers, with the regression line defined by the equation: y (chloramine-T) = 8.34 + 0.99 x (lactoperoxidase).

Erythrocyte insulin-like growth factor-I receptor evaluation in normal subjects, acromegalics, and growth hormone-deficient and insulin-dependent diabetic children.

Insulin-like growth factor-I (IGF-I) receptors are characterized in several animal and human tissues. IGF-I receptor studies performed in erythrocytes to assess IGF-I receptor status at target-cell tissues are potentially useful for clinical studies, since tissue biopsies or cultures are not required. However, validation of results is challenged by some investigators on the basis of discrepancies described in comparative studies with other cell types, probably related to populations of different cell ages affecting binding to red blood cells (RBCs). By correcting cell age for creatine, we studied IGF-I receptor status in 24 normal subjects (11 adults and 13 children, eight prepubertal and five pubertal) and 33 patients with pathologic conditions (five adult acromegalics, six children with pituitary dwarfism, and 22 type I diabetic children, 15 prepubertal and seven pubertal). Acromegalic patients with higher plasma IGF-I and insulin levels presented lower IGF-I specific binding ([Bo] mean +/- SEM, 6.1% +/- 0.8%) and affinity ([ED50] 28.5 +/- 2.2 ng/mL) than normal adults (Bo, 10.9% +/- 0.7%; ED50, 16.4 +/- 0.9 ng/mL; P < .001), and growth hormone (GH)-deficient children showed higher IGF-I binding 24.6% +/- 1.7%, P < .001) without significant affinity alterations than normal prepubertal children (Bo, 14.7% +/- 1.0%). Both prepubertal and pubertal type I diabetic children with higher GH levels presented decreased IGF-I binding (11.4% +/- 0.9% for prepubertal, P < .05; 10.0% +/- 1.1% for pubertal, P < .05) to RBC receptors in comparison to the respective control group (14.7% +/- 10% and 14.9% +/- 1.3%, prepubertal and pubertal, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Mechanism of action of phenethylbiguanide (phenformin) in man. III. interrelationship between ethanol and phenethylibiguanide (PBG) in normal and diabetic subjects.

A standard 4-hr ethanol infusion (236 mg/min) after a 3-day fast with and without phenformin (25 mg q.i.d.), with blood drawn every hour for 8 hr, was performed on five normal subjects, eight obese nondiabetics, seven obese chemical diabetics, and four nonobese diabetics. Control infusion induced in all subjects a decline in blood sugar levels during and/or after the alcohol challenge, with a parallel decrease in basal plasma insulin. Hypoglycemia and the decrease in insulin secretion were associated with increased plasma free fatty acid concentration. Addition of phenethylbiguanide (PBG) to the preparatory 3-day fast resulted in a greater drop in the blood glucose levels of the normal control subjects, obese and nonobese diabetics; in the obese nondiabetics, however, significantly lower degree of blood glucose decrease than control was elicited. Furthermore, obese nondiabetics altered their blood glucose-insulin interaction with apparent increased responsivess of the B cells of PBG. The results suggest that effects of phenformin on blood glucose levels are more dependent on the metabolic state of the patient than on a property of the drug itself.

Risk factors in obese women, with particular reference to visceral fat component.

Possible associations between increased visceral fat component and serum lipid concentrations, glucose tolerance and insulinaemia (specific radioimmunoassay) were studied as risk factors for cardiovascular disease in 50 adult obese women without known diabetes and 11 lean normal women. Visceral abdominal fat areas were evaluated by computed tomography and "true" insulin concentrations. Diabetes was observed in 6 obese women (12%) and impaired glucose tolerance in 13 (26%). In obese women, visceral fat area correlated significantly with VLDL-cholesterol, triglycerides, and systolic and diastolic blood pressure, whereas subcutaneous area correlated negatively with cholesterol and LDL-cholesterol. Insulinaemia was not increased in visceral obesity nor correlated with other risk factors. An association between increased visceral fat accumulation, dyslipidaemia and increased diastolic blood pressure was observed, but no significant correlations were noted between fasting "true" insulin or insulin response on an oral glucose tolerance test and intra-abdominal fat areas or dyslipidemia. The gender of the patients could have been an important factor in these last observations.

Preparation of high-quality iodine-125-labelled pituitary human follicle-stimulating hormone (hFSH) for radioimmunoassay: comparison of enzymatic and chloramine-T iodination.

A method is described for the enzymatic radioiodination of human follicle-stimulating hormone (hFSH) by a system consisting of lactoperoxidase, hydrogen peroxide and Na125I. It was compared with the Chloramine-T modified technique. A satisfactory specific activity of the labelled hormone was obtained with the enzymatic iodination with much greater immunoreactivity was stability than after Chloramine-T.

Comparison of plasma progesterone assay in women by competitive protein binding (CPB) and radioimmunoassay (RIA).

Plasma progesterone levels during the follicular and luteal phases were compared when measured simultaneously by competitive protein binding (using guinea pig sera as binding agent) and radioimmunoassay (antiserum against progesterone-11-alpha-succinyl bovine serum albumin in rabbits), the values obtained were significantly different within each technique, depending on whether previous thin-layer chromatographic purification of the extracts was employed or not. No significant differences were noticed between CPB and RIA when the chromatographic step was used, but when it was omitted, CPB was greater than RIA at the follicular but not at the luteal phase.

Effect of fat distribution on the pharmacokinetics of cortisol in obesity.

OBJECTIVE: Patients with predominantly upper body obesity are at greater risk for developing diabetes mellitus, hyperlipidemia, hypertension, and cardiovascular disease. Little is known about the mechanisms involved in the regulation of regional body distribution. It has been accepted that the accumulation of fat into adipose tissue depends on regional metabolic regulation of adipocytes and that glucocorticoids play a role in this mechanism. The aim of the present study is to investigate how the pharmacokinetics of cortisol correlate to intraabdominal and subcutaneous fat distribution in obese patients. METHODS: A group of 24 obese patients (13 males and 11 females) were submitted to a CT scan for intraabdominal and subcutaneous fat area evaluation. A 30-min cortisol infusion (0.25 mg/kg) was administered and plasma cortisol was measured over 6 hours. RESULTS: Patients with larger intraabdominal fat areas were found to have a higher cortisol clearance than those with lower intraabdominal fat areas. Cortisol clearance (both, absolute and body-weight corrected) showed a statistically significant correlation with intraabdominal fat area, either expressed by waist-hip ratio or obtained by computerized tomography. CONCLUSIONS: These findings indicate a more effective clearance capability for cortisol in patients with central obesity resulting in lowered cortisol plasma levels despite an increased cortisol secretion observed in this patient group.

[Treatment of growth hormone deficiency patients with authentic recombinant growth hormone]. / Tratamento de pacientes portadores de deficiência de hormônio de crescimento (DHC) com hormônio de crescimento recombinante autêntico.

Eleven growth hormone deficient (GHD) subjects were treated regularly for 3 years with an authentic recombinant growth hormone preparation (0.35 to 0.5U/kg/week). Growth velocity (GV) increased from a mean o 2.91 +/- 1.58cm/year during the 1st year to 8.62 +/- 2.81cm/y in the 2nd and 7.63 +/- 1.84cm/y in the 3th year of follow up. During that period height age (delta HA) increased by 4.9 +/- 1 years while bone age advanced 4.3 +/- 1.4 year (delta BA) resulting in a delta HA/delta BA of 1.1 +/- 0.2. Since the height increment was associated with BA advancement the final height within normal range could not be attained. Thus, GHr therapy should be instituted before the height deficit would became intense as it happened in the majority of our patients. Early diagnosis and therapy of GHD is important, when growth retardation is less severe, in order to allow a better final height.