Does genetic testing offer utility as a supplement to traditional family health history intake for inherited disease risk?

CONTENT

This study examines the potential utility of genetic testing as a supplement to family health history to screen for increased risk of inherited disease. Medical conditions are often misreported or misunderstood, especially those related to different forms of cardiac disease (arrhythmias vs. structural heart disease vs. coronary artery disease), female organ cancers (uterine vs. ovarian vs. cervical), and type of cancer (differentiating primary cancer from metastases to other organs). While these nuances appear subtle, they can dramatically alter medical management. For example, different types of cardiac failure (structural, arrhythmia, and coronary artery disease) have inherited forms that are managed with vastly different approaches.

METHODS

Using a dataset of over 6,200 individuals who underwent genetic screening, we compared the ability of genetic testing and traditional family health history to identify increased risk of inherited disease. A further, in-depth qualitative study of individuals for whom risk identified through each method was discordant, explored whether this discordance could be addressed through changes in family health history intake.

FINDINGS

Of 90 individuals for whom genetic testing indicated significant increased risk for inherited disease, two-thirds (66%) had no corroborating family health history. Specifically, we identify cardiomyopathy, arrhythmia, and malignant hyperthermia as conditions for which discordance between genetic testing and traditional family health history was greatest, and familial hypercholesterolaemia, Lynch syndrome, and hereditary breast and ovarian cancer as conditions for which greater concordance existed.

CONCLUSION

We conclude that genetic testing offers utility as a supplement to traditional family health history intake over certain conditions.

Information-seeking preferences in diverse patients receiving a genetic testing result in the Clinical Sequencing Evidence-Generating Research (CSER) study

PURPOSE

Accurate and understandable information after genetic testing is critical for patients, family members, and professionals alike.

METHODS

As part of a cross-site study from the Clinical Sequencing Evidence-Generating Research consortium, we investigated the information-seeking practices among patients and family members at 5 to 7 months after genetic testing results disclosure, assessing the perceived utility of a variety of information sources, such as family and friends, health care providers, support groups, and the internet.

RESULTS

We found that individuals placed a high value on information obtained from genetics professionals and health care workers, independent of genetic testing result case classifications as positive, inconclusive, or negative. The internet was also highly utilized and ranked. Study participants rated some information sources as more useful for positive results compared with inconclusive or negative outcomes, emphasizing that it may be difficult to identify helpful information for individuals receiving an uncertain or negative result. There were few data from non-English speakers, highlighting the need to develop strategies to reach this population.

CONCLUSION

Our study emphasizes the need for clinicians to provide accurate and comprehensible information to individuals from diverse populations after genetic testing.

A study of elective genome sequencing and pharmacogenetic testing in an unselected population

BACKGROUND

Genome sequencing (GS) of individuals without a medical indication, known as elective GS, is now available at a number of centers around the United States. Here we report the results of elective GS and pharmacogenetic panel testing in 52 individuals at a private genomics clinic in Alabama.

METHODS

Individuals seeking elective genomic testing and pharmacogenetic testing were recruited through a private genomics clinic in Huntsville, AL. Individuals underwent clinical genome sequencing with a separate pharmacogenetic testing panel.

RESULTS

Six participants (11.5%) had pathogenic or likely pathogenic variants that may explain one or more aspects of their medical history. Ten participants (19%) had variants that altered the risk of disease in the future, including two individuals with clonal hematopoiesis of indeterminate potential. Forty-four participants (85%) were carriers of a recessive or X-linked disorder. All individuals with pharmacogenetic testing had variants that affected current and/or future medications.

CONCLUSION

Our study highlights the importance of collecting detailed phenotype information to interpret results in elective GS.

SYT1-associated neurodevelopmental disorder: a case series

Synaptotagmin 1 (SYT1) is a critical mediator of fast, synchronous, calcium-dependent neurotransmitter release and also modulates synaptic vesicle endocytosis. This paper describes 11 patients with de novo heterozygous missense mutations in SYT1. All mutations alter highly conserved residues, and cluster in two regions of the SYT1 C2B domain at positions Met303 (M303K), Asp304 (D304G), Asp366 (D366E), Ile368 (I368T) and Asn371 (N371K). Phenotypic features include infantile hypotonia, congenital ophthalmic abnormalities, childhood-onset hyperkinetic movement disorders, motor stereotypies, and developmental delay varying in severity from moderate to profound. Behavioural characteristics include sleep disturbance and episodic agitation. Absence of epileptic seizures and normal orbitofrontal head circumference are important negative features. Structural MRI is unremarkable but EEG disturbance is universal, characterized by intermittent low frequency high amplitude oscillations. The functional impact of these five de novo SYT1 mutations has been assessed by expressing rat SYT1 protein containing the equivalent human variants in wild-type mouse primary hippocampal cultures. All mutant forms of SYT1 were expressed at levels approximately equal to endogenous wild-type protein, and correctly localized to nerve terminals at rest, except for SYT1M303K, which was expressed at a lower level and failed to localize at nerve terminals. Following stimulation, SYT1I368T and SYT1N371K relocalized to nerve terminals at least as efficiently as wild-type SYT1. However, SYT1D304G and SYT1D366E failed to relocalize to nerve terminals following stimulation, indicative of impairments in endocytic retrieval and trafficking of SYT1. In addition, the presence of SYT1 variants at nerve terminals induced a slowing of exocytic rate following sustained action potential stimulation. The extent of disturbance to synaptic vesicle kinetics is mirrored by the severity of the affected individuals' phenotypes, suggesting that the efficiency of SYT1-mediated neurotransmitter release is critical to cognitive development. In summary, de novo dominant SYT1 missense mutations are associated with a recognizable neurodevelopmental syndrome, and further cases can now be diagnosed based on clinical features, electrophysiological signature and mutation characteristics. Variation in phenotype severity may reflect mutation-specific impact on the diverse physiological functions of SYT1.

Effect of warning on feigned malingering on the WAIS-R in college samples

Research indicates claimant malingering of cognitive deficits to be common in personal injury litigation. Efforts have been made to either detect such tendencies or deter efforts at malingering. The present study examined whether warning people that feigned malingering efforts would be detected results in more valid profiles on the Wechsler Adult Intelligence Scale-Revised. Undergraduates (N = 48) were randomly assigned to one of three conditions: feigned malingerers without warning, feigned malingerers with warning, and controls. Analysis indicated both feigned malingerer groups performed significantly worse than the control group; however, feigned malingerers with warning did not perform significantly better than those without warning. Unlike previous research using the Wechsler Memory Scale-Revised, results did not support effectiveness of warning in reducing feigned malingering scores.

Prospective 10-year evaluation of hypobetalipoproteinemia in a cohort of 772 firefighters and cross-sectional evaluation of hypocholesterolemia in 1,479 men in the National Health and Nutrition Examination Survey I

Our specific aim in a 10-year prospective study of 772 Cincinnati firemen (predominantly aged 26 to 46 years) was to determine the prevalence, attributes, and etiology of persistent hypobetalipoproteinemia, defined by entry low-density lipoprotein cholesterol (LDLC) less than 75 mg/dL. A second specific aim was to cross-sectionally assess hypocholesterolemia (defined by total serum cholesterol [TC] < 130 mg/dL) in 1,314 white and 165 black men aged 26 to 46 years in the National Health and Nutrition Examination Survey (NHANES I). The 141 black and 631 white firemen had 4,973 person-years of follow-up time (median, 7.1 yr/man). Of 772 men, 44 (5.7%) had entry LDL levels less than 75 mg/dL; they had a mean follow-up time of 7.3 yr/man. Of these 44 men, there were 12 (1.8% of the cohort) with entry LDLC less than 75 mg/dL, and at least 67% of their follow-up LDLC levels were less than 75. Their mean entry TC and LDLC levels were low (130 and 58 mg/dL), mean triglyceride (TG) was low (63 mg/dL), and mean high-density lipoprotein cholesterol (HDLC) was high (60 mg/dL), LDLC remained at less than 75 mg/dL in 81% of their follow-up samples. Their mean entry and follow-up cholesterol and LDLC did not differ (P > .1, 130 v 133 mg/dL and 58 v 63 mg/dL). Compared with 32 men with entry LDLC less than 75 mg/dL but with less than 87% of follow-up LDLC less than 75 mg/dL, the 12 men with persistently low LDLC had lower mean Quetelet indices and diastolic blood pressure at entry (2.36 v 2.58, P = .056; 73 v 80 mm Hg, P = .03) and on follow-up study (2.45 v 2.69, P = .04; 72 v 79 mm Hg, P = .05). Of 12 men with persistently low LDLC, two had truncated apolipoprotein (apo) B (familial hypobetalipoproteinemia, two had the apo E genotype 2/3, and two had acquired hypobetalipoproteinemia that antedated mortality from melanoma by 9 years and from alcoholism by 2 years. Comparable to white and black firemen aged 26 to 46 years, 2.9% and 3.6% of whom had entry serum TC less than 130 mg/dL, of 1,314 white and 165 black men in the NHANES I study (aged 26 to 46), 1.8% and 3.6% had hypocholesterolemia (entry TC < 130 mg/dL). Daily mean calorie, fat, and protein intake (grams per day) did not differ (P > .05) in men with entry TC less than 130 mg/dL compared with those with TC 130 to 230 or greater than 230 mg/dL. Hypocholesterolemia in white and black men in NHANES I could not be attributed to hypocaloric intake or to protein, fat, or carbohydrate undernutrition. There appear to be racial differences in the prevalence of hypocholesterolemia. Blacks comprised 18% of the firemen's cohort but 42% of those with persistent hypobetalipoproteinemia; among NHANES I subjects, 3.6% of blacks were hypocholesterolemic versus 1.8% of whites. Unless persistent hypobetalipoproteinemia reflects an underlying disease, alcoholism, etc., it is often heritable, and may be associated with a reduced likelihood of coronary heart disease (CHD) and with increased longevity.

Risk factors for coronary heart disease among firefighters in Cincinnati

Since 1984, coronary heart disease (CHD) risk factors have been prospectively assessed among Cincinnati firefighters free of CHD at study entry. In total, 806 firemen with a mean age of 37 years at entry have been followed for 6.4 years on average, contributing 5,173 person-years. CHD risk factors were measured every 1-4 years and included weight, blood pressure, cigarette use, fasting glucose, and lipid profile. When, in aggregate, these CHD risk factors were found to be in a high risk range, suggestions were made serially to reduce CHD risk. A composite high CHD risk factor score led to an exercise electrocardiogram (ECG) with thallium scan, which was repeated every 1-4 years. Myocardial infarction (MI) occurred in 7 men, with 1.35 MIs/1,000 man-years; 15 others developed CHD, with 4.25 MI + CHD/1,000 man-years. The firefighters' MI event rate (1.35 MIs/1,000 man-years) was lower (but not significantly, p > 0.1) than that for employed 30- to 39-year-old men free of CHD at entry (2.07/1,000 man years), who had an average follow-up of 5.4 years in the NHANES I study. At study entry, the 22 men who later developed CHD (vs. the 784 who did not develop CHD) were older (p = .0001), smoked more (p = .0001), and were more likely to have first degree relatives with CHD before age 60 (p = .017). After covariance adjusting for age, race, and Quetelet index, men with CHD (vs. those CHD free) had higher systolic and diastolic blood pressures (p = .0001, .0001), higher LDL cholesterol (p = .04), higher total cholesterol (p = .014), and higher triglycerides (p = .03). By Poisson regression, significant independent predictors of CHD events were age (p = .0007), cigarette smoking (p = .001), diastolic blood pressure (p = .056), and family history of CHD at age < or = 60 (p = .048). Men who later developed CHD and those without CHD did not differ by history of smoke inhalation (p > 0.3). The calculated ratio of savings to cost attributable to the program per year was 5.9/1 ($258,500/$43,600). In the current study, firefighting as an occupation was not associated with increased CHD event rates. CHD events that did develop were, for the most part, associated with modifiable CHD risk factors.

Replication initiator protein of plasmid R6K autoregulates its own synthesis at the transcriptional step

The replication initiator protein of plasmid R6K preferentially repressed transcription initiated in vitro from the promoter of the initiator protein cistron. DNase I protection experiments revealed that the sequences in the region of the promoter recognized by the initiator protein partially overlapped the sequences of the same promoter recognized by RNA polymerase of Escherichia coli. Competitive DNase I protection experiments revealed that the initiator not only prevented the RNA polymerase from binding to the promoter sequence but also displaced RNA polymerase from preformed enzyme-promoter binary complexes. Thus, the initiator protein acts as a transcriptional repressor of its own cistron by either preventing RNA polymerase from binding to the promoter or by displacing RNA polymerase from promoter-enzyme complexes.

Bacillus stearothermophilus Disc Assay for Detection of Inhibitors in Milk: Collaborative Study

A 2-part (A and B) collaborative study was conducted on a Bacillus stearothermophilus paper disc (12.7 mm) method to detect residual inhibitors in milk. The 18 participating collaborators assayed raw milk samples spiked with a beta-lactam (penicillin G). Of the 18 collaborators, 14 participated in part A and 16 in part B. Part A demonstrated that either Antibiotic Medium No. 4 or PM Indicator Agar is suitable for use in the assay. The lowest concentration detectable, not significantly different from 100% at the α = 0.05 level, was 0.008 unit/mL with either medium. Part B demonstrated that the sensitivity of the method is equal to that of the current AOAC method (16.131- 16.136). The concentration of beta-lactam detected by 50% of the analysts was 0.003-0.005 unit/mL in this study, compared with 0.005 unit/mL reported in an earlier collaborative study on the current AOAC method. No false positive results were reported in part A or part B. All samples found positive by the confirmatory test in part B were correctly identified as a beta-lactam with commercial Penase discs. The lowest concentration detectable by the method, not significantly different from 100% at the α = 0.05 level, was 0.008 unit/mL. The method was adopted official first action.

Metastatic adenocarcinoma of synovium presenting as an acute arthritis. Diagnosis by closed synovial biopsy

An acute arthritis may accompany the onset of cancer. A case of metastatic adenocarcinoma of the synovium presenting as an acute arthritis is described. The diagnostic importance of a careful synovial fluid analysis and the use of closed synovial biopsy are emphasized.