Whole-exome sequencing for mutation detection in pediatric disorders of insulin secretion: Maturity onset diabetes of the young and congenital hyperinsulinism.

BACKGROUND: To assess the utility of whole-exome sequencing (WES) for mutation detection in maturity-onset diabetes of the young (MODY) and congenital hyperinsulinism (CHI). MODY and CHI are the two commonest monogenic disorders of glucose-regulated insulin secretion in childhood, with 13 causative genes known for MODY and 10 causative genes identified for CHI. The large number of potential genes makes comprehensive screening using traditional methods expensive and time-consuming. METHODS: Ten subjects with MODY and five with CHI with known mutations underwent WES using two different exome capture kits (Nimblegen SeqCap EZ Human v3.0 Exome Enrichment Kit, Nextera Rapid Capture Exome Kit). Analysis was blinded to previously identified mutations, and included assessment for large deletions. The target capture of five exome capture technologies was also analyzed using sequencing data from >2800 unrelated samples. RESULTS: Four of five MODY mutations were identified using Nimblegen (including a large deletion in HNF1B). Although targeted, one mutation (in INS) had insufficient coverage for detection. Eleven of eleven mutations (six MODY, five CHI) were identified using Nextera Rapid (including the previously missed mutation). On reconciliation, all mutations concorded with previous data and no additional variants in MODY genes were detected. There were marked differences in the performance of the capture technologies. CONCLUSIONS: WES can be useful for screening for MODY/CHI mutations, detecting both point mutations and large deletions. However, capture technologies require careful selection.

The genetic associations of acute anterior uveitis and their overlap with the genetics of ankylosing spondylitis.

Acute anterior uveitis (AAU) involves inflammation of the iris and ciliary body of the eye. It occurs both in isolation and as a complication of ankylosing spondylitis (AS). It is strongly associated with HLA-B*27, but previous studies have suggested that further genetic factors may confer additional risk. We sought to investigate this using the Illumina Exomechip microarray, to compare 1504 cases with AS and AAU, 1805 with AS but no AAU and 21 133 healthy controls. We also used a heterogeneity test to test the differences in effect size between AS with AAU and AS without AAU. In the analysis comparing AS+AAU+ cases versus controls, HLA-B*27 and HLA-A*02:01 were significantly associated with the presence of AAU (P<10(-300) and P=6 × 10(-8), respectively). Secondary independent association with PSORS1C3 (P=4.7 × 10(-5)) and TAP2 (P=1.1 × 10(-5)) were observed in the major histocompatibility complex. There was a new suggestive association with a low-frequency variant at zinc-finger protein 154 in the AS without AAU versus control analysis (zinc-finger protein 154 (ZNF154), P=2.2 × 10(-6)). Heterogeneity testing showed that rs30187 in ERAP1 has a larger effect on AAU compared with that in AS alone. These findings also suggest that variants in ERAP1 have a differential impact on the risk of AAU when compared with AS, and hence the genetic risk for AAU differs from AS.

COL1A1 C-propeptide cleavage site mutation causes high bone mass, bone fragility and jaw lesions: a new cause of gnathodiaphyseal dysplasia?

Gnathodiaphyseal dysplasia (GDD) is a rare autosomal dominant condition characterized by bone fragility, irregular bone mineral density (BMD) and fibro-osseous lesions in the skull and jaw. Mutations in Anoctamin-5 (ANO5) have been identified in some cases. We aimed to identify the causative mutation in a family with features of GDD but no mutation in ANO5, using whole exome capture and massive parallel sequencing (WES). WES of two affected individuals (a mother and son) and the mother's unaffected parents identified a mutation in the C-propeptide cleavage site of COL1A1. Similar mutations have been reported in individuals with osteogenesis imperfecta (OI) and paradoxically increased BMD. C-propeptide cleavage site mutations in COL1A1 may not only cause 'high bone mass OI', but also the clinical features of GDD, specifically irregular sclerotic BMD and fibro-osseous lesions in the skull and jaw. GDD patients negative for ANO5 mutations should be assessed for mutations in type I collagen C-propeptide cleavage sites.

Whole exome sequencing is an efficient, sensitive and specific method for determining the genetic cause of short-rib thoracic dystrophies.

Short-rib thoracic dystrophies (SRTDs) are congenital disorders due to defects in primary cilium function. SRTDs are recessively inherited with mutations identified in 14 genes to date (comprising 398 exons). Conventional mutation detection (usually by iterative Sanger sequencing) is inefficient and expensive, and often not undertaken. Whole exome massive parallel sequencing has been used to identify new genes for SRTD (WDR34, WDR60 and IFT172); however, the clinical utility of whole exome sequencing (WES) has not been established. WES was performed in 11 individuals with SRTDs. Compound heterozygous or homozygous mutations were identified in six confirmed SRTD genes in 10 individuals (IFT172, DYNC2H1, TTC21B, WDR60, WDR34 and NEK1), giving overall sensitivity of 90.9%. WES data from 993 unaffected individuals sequenced using similar technology showed two individuals with rare (minor allele frequency <0.005) compound heterozygous variants of unknown significance in SRTD genes (specificity >99%). Costs for consumables, laboratory processing and bioinformatic analysis were

The fate of the chemical warfare agent during DNA extraction.

Forensic laboratories do not have the infrastructure to process or store contaminated DNA samples that have been recovered from a crime scene contaminated with chemical or biological warfare agents. Previous research has shown that DNA profiles can be recovered from blood exposed to several chemical warfare agents after the agent has been removed. The fate of four toxic agents, sulfur mustard, sodium 2-fluoroacetate, sarin, and diazinon, in a lysis buffer used in Promega DNA IQ extraction protocol was studied to determine if extraction would render the samples safe. Two independent analytical methods were used per agent, selected from GC-MS, 1H NMR, 19F NMR, (31)P NMR, or LC-ES MS. The methods were validated before use. Determinations were carried out in a semi-quantitative way, by direct comparison to standards. Agent levels in the elution buffer were found to be below the detectable limits for mustard, sarin, sodium 2-fluoroacetate or low (<0.02 mg/mL) for diazinon. Therefore, once extracted these DNA samples could be safely processed in a forensic laboratory.

Comparative knowledge and practice of emergency physicians, cardiologists, and primary care practitioners regarding drug therapy for acute myocardial infarction.

OBJECTIVES: This study assesses the knowledge and practice of emergency physicians regarding the treatment of acute myocardial infarction (AMI) and compares the results with previously published data on cardiologists and primary care practitioners. BACKGROUND: Debate surrounding the respective roles of emergency physicians, primary care practitioners, and specialists figures prominently in discussions regarding the nation's evolving health-care system. Data are lacking about the comparative knowledge and practice of emergency physicians, cardiologists, and primary care practitioners regarding conditions commonly treated by all three groups, eg, AMI. METHODS: A survey of 1,045 emergency physicians, nationally, was conducted in 1995 regarding five short-term pharmacologic interventions employed for many years in the standard treatment of AMI. The emergency physicians were questioned about the effect on survival of each intervention and the likelihood that they would prescribe each intervention. The findings were then compared with previously published data on the knowledge and practice of cardiologists and primary care practitioners obtained in New York and Texas in 1993. Identical clinical queries and eligibility criteria were employed in all groups. RESULTS: The responding emergency physicians' knowledge was similar or significantly greater than that of responding cardiologists for the effect on survival of most of the short-term interventions, and their practice patterns were similar or significantly better than responding cardiologists for all interventions studied. Emergency physicians and cardiologists had significantly better knowledge and practice in this area compared with responding primary care practitioners. CONCLUSIONS: For the management of AMI, emergency physicians, on average, have a similar or greater awareness of the effects on survival and similar or better practice patterns regarding most acute pharmacologic interventions when compared with those of cardiologists; both groups, on average, have a superior knowledge and practice when compared with primary care practitioners. These results illustrate the importance of emergency medicine and support further consideration of an expanding role for the emergency physician in the nation's evolving health-care system.

Serial electrocardiograms for chest pain patients with initial nondiagnostic electrocardiograms: implications for thrombolytic therapy.

OBJECTIVES: To determine the proportion of acute myocardial infarction (AMI) patients without ST-segment elevation who subsequently develop ST-segment elevation during their hospital courses; and to compare demographics and presenting features of AMI patient subgroups: those with initial ST-segment elevation, those with in-hospital ST-segment elevation, and those with no ST-segment elevation. METHODS: A retrospective cohort analysis of admitted chest pain patients who had a hospital discharge diagnosis of AMI was performed. Each chart was examined for initial ECG interpretation, serial ECG analysis, patient age, gender, cardiac risk factors, in-hospital survival, time between sequential ECGs, and number of ECGs performed within the first 48 hours of hospital admission. RESULTS: Of the 114 charts reviewed, 20 patients had ECGs meeting thrombolytic criteria on arrival. Of the 94 AMI patients who had nondiagnostic ECGs on arrival, 19 (20%) subsequently developed ECG changes meeting thrombolytic criteria. Seven patients developed these changes within eight hours of the initial ECG, four from eight to 12 hours after, two from 12 to 24 hours after, and six more than 24 hours after. Most patients who had documented AMIs did not develop ECG criteria for thrombolytic therapy during their hospitalizations. Male gender and smoking history were more commonly associated with late ST-segment elevation for those presenting with nondiagnostic ECGs. All the patients who had late diagnostic ECG changes survived to hospital discharge. Serial ECGs were performed more frequently in the group who had initially diagnostic ECGs and least frequently in the group who did not develop ST-segment elevation during their hospitalizations. CONCLUSIONS: Most patients with AMI do not meet ECG criteria for the administration of thrombolytic therapy. A significant minority (20%) of the admitted chest pain patients with subsequently confirmed AMIs developed ECG criteria for thrombolytics during their hospitalizations. Further attention to such patients who have delayed ST-segment elevation is warranted. A standardized in-hospital serial ECG protocol should be considered to identify admitted patients who develop criteria for thrombolytic or other coronary revascularization therapy.

Postoperative mitral valve abscess. A case report.

The authors report a case of a patient with postoperative perimitral bioprosthetic abscess and probable systemic embolization. The location of the abscess is not common and the use of porcine bioprostheses is supposedly associated with a low rate of embolic complications. Because of the high mortality and morbidity, it is stressed that patients with prosthetic valve endocarditis should be managed aggressively with surgery.

Complications from the use of thrombolytic agents in patients with cocaine associated chest pain.

Previous investigators have noted that patients with cocaine associated chest pain frequently have abnormal electrocardiograms, including ST segment elevation, in the absence of ongoing myocardial ischemia. The effects of these nonischemic ST segment elevations have not been evaluated. We report two patients with cocaine associated chest pain and ST segment elevations who received thrombolytic agents in the absence of myocardial ischemia. Neither patient sustained a myocardial infarction, nor had clinical evidence of reperfusion. The ST segment elevations persisted after resolution of chest pain in both patients, and both of the patients experienced complications of thrombolytic therapy. One patient sustained a hemorrhagic stroke and one had minor oral-pharyngeal bleeding. Given the lack of documented efficacy, concerns about safety, and poor specificity of the electrocardiogram for myocardial ischemia in patients with cocaine associated chest pain, thrombolytic therapy should be used with caution in these patients.

The role of serum phosphate level and acute ischemic bowel disease.

The objectives of this study were to determine whether an elevated serum phosphate level is predictive of acute ischemic bowel disease and whether it serves as a prognostic indicator in patients with intestinal ischemia. A retrospective chart review was performed at an urban teaching hospital emergency department. Twenty-three patients with documented acute ischemic bowel disease from 1990 through 1994 were compared with 27 patients with acute abdominal disease entities unrelated to intestinal ischemia. The sensitivity, specificity, and positive and negative predictive values of serum phosphate were 26%, 85%, 60%, and 58% respectively. Levels of phosphate in patients with intestinal ischemia versus controls were 4.20 versus 3.41 mg/dL (P = .1338). The length of bowel necrosis in the experimental group with elevated phosphate versus normal phosphate level was 57.53 cm versus 99.00 cm (P = .4132). Although not statistically significant, linear regression revealed slightly positive correlations in those with elevated phosphate versus normal phosphate level (in the experimental group) with the length of bowel necrosis and duration of hospital stay as r= .155 (P = .4813) and r= .134 (P= .5418), respectively. Serum phosphate level independently has no diagnostic or prognostic value in acute ischemic bowel disease.

Hemolytic uremic syndrome: just another case of gastroenteritis?

Hemolytic uremic syndrome (HUS), the most common cause of acute renal failure in childhood, has the potential to progress to a life-threatening illness. Its incidence in North America is increasing. Several studies have shown that Escherichia coli O157:H7 is associated with HUS. Although this pathogen was first recognized more than 10 years ago and is relatively common, many physicians are not aware of this diagnosis let alone the spectrum of illness associated with the bacteria. This case exemplifies what appears initially as gastroenteritis but, ultimately, becomes the final diagnosis of HUS. A case is presented to provide additional education to ensure the E coli O157:H7 infection is considered in the differential diagnosis of persons who present with bloody diarrhea.

Heroin bodypacking.

Drug smuggling by internal bodily concealment is a well-recognized international problem, particularly in view of the difficulty of its detection and the potential for large financial gains. This mode of transport can have serious medical complications, including drug intoxication--sometimes fatal--as well as intestinal obstruction by foreign bodies (FBs). We discuss a case of heroin 'bodypacking' (the ingestion of heroin filled condoms) with its resultant complications. The initial medical management and indications for surgery are discussed, and the relevant literature reviewed.

Cocaine-associated intestinal gangrene in a pregnant woman.

A 31-year-old pregnant woman who was an active cocaine abuser presented to our emergency department five times in 1 week for abdominal pain and vomiting. She continued to use cocaine regularly despite having abdominal pain. Her fifth admission was for seizures. There were no objective signs of peritoneal inflammation and the rectal guiac examination was repeatedly negative. The patient progressed to severe septic shock. Intraabdominal sepsis and/or bowel perforation was suspected. Exploratory laporatomy revealed gangrene and perforation of the small intestine and fecal peritonitis. She rapidly developed multiorgan failure and died. Gastrointestinal complications resulting from cocaine use are uncommon. Our case is unique in that the patient was pregnant, used cocaine by the intranasal route, and lacked objective signs of acute abdomen. Emergency physicians should be aware of the morbidity associated with the use of cocaine.

Phenylpropanolamine and associated myocardial injury.

We report the cases of two patients without significant past medical history in whom developed myocardial injury attributed to the use of anorectic agents containing phenylpropanolamine. The pharmacologic properties of phenylpropanolamine and the current management of common adverse reactions to phenylpropanolamine are briefly reviewed.

The utility of maternal creatine kinase in the evaluation of ectopic pregnancy.

This investigation was designed to evaluate the utility of maternal creatine phosphokinase (CPK) in predicting the presence of an ectopic pregnancy (EP) in an emergency department (ED) setting. Twenty-one patients with the diagnosis of EP were randomly matched (1:1) with pregnant patients who subsequently ruled-out for EP. Serum CPK values at presentation were compared between the groups using two-tailed ANOVA, odds ratio, and frequency tables were generated using our a priori hypothesis that a serum CPK of >70 mlU/dL may be useful as a predictor of EP. The mean serum CPK was 118mlU/dL in the EP group and 64 mlU/dL in the non-EP group (P < .0031). Controlling for age, race, and gestational age, there was an association between elevated serum CPK and EP in our study population (with an odds ratio of 6.5). The categorical evaluation (with 95% confidence interval [CI]) of CPK (>70 mIU/dL) as a predictor of EP follows: sensitivity - 100% (80.8 to 100); specificity-- 61.9% (38.7 to 81); PV(+) - 72.4% (52.5 to 88.6); PV(-) - 100% (71.7 to 100). We therefore conclude that a CPK level >70 mIU/dL may serve as an important adjuvant diagnostic tool in ruling-out EP.

Collisional frequency shifts in 133Cs fountain clocks.

We present a theoretical analysis of the density dependent frequency shift in Cs fountain clocks using the highly constrained binary collision model described by Leo et al. [Phys. Rev. Lett. 85, 2721 (2000)]. We predict a reversal in the clock shift at temperatures near 0.08 microK. Our results show that s waves dominate the collision process. However, as a consequence of the large scattering lengths in Cs the clock shift is strongly temperature dependent and does not reach a constant Wigner-law value until temperatures are less than 0.1 nK.