Myotonic dystrophy type 1 testing, 2024 revision: A technical standard of the American College of Medical Genetics and Genomics (ACMG).

Myotonic dystrophy type 1 (DM1) is a form of muscular dystrophy causing progressive muscle loss and weakness. Although clinical features can manifest at any age, it is the most common form of muscular dystrophy with onset in adulthood. DM1 is an autosomal dominant condition, resulting from an unstable CTG expansion in the 3'-untranslated region of the myotonic dystrophy protein kinase (DMPK) gene. The age of onset and the severity of the phenotype are roughly correlated with the size of the CTG expansion. Multiple methodologies can be used to diagnose affected individuals with DM1, including polymerase chain reaction, Southern blot, and triplet repeat-primed polymerase chain reaction. Recently, triplet repeat interruptions have been described, which may affect clinical outcomes of a fully-variable allele in DMPK. This document supersedes the Technical Standards and Guidelines for Myotonic Dystrophy originally published in 2009 and reaffirmed in 2015. It is designed for genetic testing professionals who are already familiar with the disease and the methods of analysis.

Systematic evidence-based review: The application of noninvasive prenatal screening using cell-free DNA in general-risk pregnancies.

PURPOSE: Noninvasive prenatal screening (NIPS) using cell-free DNA has been assimilated into prenatal care. Prior studies examined clinical validity and technical performance in high-risk populations. This systematic evidence review evaluates NIPS performance in a general-risk population. METHODS: Medline (PubMed) and Embase were used to identify studies examining detection of Down syndrome (T21), trisomy 18 (T18), trisomy 13 (T13), sex chromosome aneuploidies, rare autosomal trisomies, copy number variants, and maternal conditions, as well as studies assessing the psychological impact of NIPS and the rate of subsequent diagnostic testing. Random-effects meta-analyses were used to calculate pooled estimates of NIPS performance (P < .05). Heterogeneity was investigated through subgroup analyses. Risk of bias was assessed. RESULTS: A total of 87 studies met inclusion criteria. Diagnostic odds ratios were significant (P < .0001) for T21, T18, and T13 for singleton and twin pregnancies. NIPS was accurate (≥99.78%) in detecting sex chromosome aneuploidies. Performance for rare autosomal trisomies and copy number variants was variable. Use of NIPS reduced diagnostic tests by 31% to 79%. Conclusions regarding psychosocial outcomes could not be drawn owing to lack of data. Identification of maternal conditions was rare. CONCLUSION: NIPS is a highly accurate screening method for T21, T18, and T13 in both singleton and twin pregnancies.

Laboratory testing for fragile X, 2021 revision: a technical standard of the American College of Medical Genetics and Genomics (ACMG).

Molecular genetic testing of the FMR1 gene is commonly performed in clinical laboratories. Pathogenic variants in the FMR1 gene are associated with fragile X syndrome, fragile X-associated tremor ataxia syndrome (FXTAS), and fragile X-associated primary ovarian insufficiency (FXPOI). This document provides updated information regarding FMR1 pathogenic variants, including prevalence, genotype-phenotype correlations, and variant nomenclature. Methodological considerations are provided for Southern blot analysis and polymerase chain reaction (PCR) amplification of FMR1, including triplet repeat-primed and methylation-specific PCR.The American College of Medical Genetics and Genomics (ACMG) Laboratory Quality Assurance Committee has the mission of maintaining high technical standards for the performance and interpretation of genetic tests. In part, this is accomplished by the publication of the document ACMG Technical Standards for Clinical Genetics Laboratories, which is now maintained online ( http://www.acmg.net ). This subcommittee also reviews the outcome of national proficiency testing in the genetics area and may choose to focus on specific diseases or methodologies in response to those results. Accordingly, the subcommittee selected fragile X syndrome to be the first topic in a series of supplemental sections, recognizing that it is one of the most frequently ordered genetic tests and that it has many alternative methods with different strengths and weaknesses. This document is the fourth update to the original standards and guidelines for fragile X testing that were published in 2001, with revisions in 2005 and 2013, respectively.This versionClarifies the clinical features associated with different FMRI variants (Section 2.3)Discusses important reporting considerations (Section 3.3.1.3)Provides updates on technology (Section 4.1).

The Use of a Game-Based Decision Aid to Educate Pregnant Women about Prenatal Screening: A Randomized Controlled Study.

PURPOSE: This project developed and evaluated the efficacy of a game decision aid among pregnant women about prenatal screening in a randomized controlled study. STUDY DESIGN: Participants were recruited from an obstetric clinic of an academic urban medical center and randomized (n = 73) to one of two study groups: the control group (n = 39) that used a brochure or the intervention group (n = 34) that also used a game decision aid. RESULT: Participants who played the game had higher knowledge scores (m = 21.41, standard deviation [SD] = 1.74) than participants in the control group (m = 19.59; SD = 3.31), p = 0.004. The median time of game playing was 6:43 minutes (range: 2:17-16:44). The groups were similar in frequency of completing screening after the study, control = 6 (15%) versus intervention = 11 (32%), p = 0.087. However, the more interaction with the game resulted in more positive attitudes toward screening. CONCLUSION: The addition of a game decision aid was effective in educating pregnant women about prenatal screening. As other genetic testing decisions continue to increase within clinical care, game-based decision tools may be a constructive method of informed decision-making.

Obstetric and gynecologic ultrasound curriculum and competency assessment in residency training programs: consensus report.

Ultrasound imaging has become integral to the practice of obstetrics and gynecology. With increasing educational demands and limited hours in residency programs, dedicated time for training and achieving competency in ultrasound has diminished substantially. The American Institute of Ultrasound in Medicine assembled a multisociety task force to develop a consensus-based, standardized curriculum and competency assessment tools for obstetric and gynecologic ultrasound training in residency programs. The curriculum and competency assessment tools were developed based on existing national and international guidelines for the performance of obstetric and gynecologic ultrasound examinations and thus are intended to represent the minimum requirement for such training. By expert consensus, the curriculum was developed for each year of training, criteria for each competency assessment image were generated, the pass score was established at, or close to, 75% for each, and obtaining a set of 5 ultrasound images with pass score in each was deemed necessary for attaining each competency. Given the current lack of substantial data on competency assessment in ultrasound training, the task force expects that the criteria set forth in this document will evolve with time. The task force also encourages use of ultrasound simulation in residency training and expects that simulation will play a significant part in the curriculum and the competency assessment process. Incorporating this training curriculum and the competency assessment tools may promote consistency in training and competency assessment, thus enhancing the performance and diagnostic accuracy of ultrasound examination in obstetrics and gynecology.

How to Integrate Cell-Free DNA Screening With Sonographic Markers for Aneuploidy: An Update.

OBJECTIVE: The sonologist detects a so-called "soft marker" during approximately 10% of routine second-trimester anatomy examinations and is often uncertain about what further management is appropriate. This article will specifically address the management of patients with sonographic markers for six common entities: choroid plexus cysts (CPCs), ventriculomegaly (VM), echogenic intracardiac focus (EIF), urinary tract dilation (UTD), fetal echogenic bowel (FEB), and femoral and humeral shortening. The use of cell-free DNA screening and its relationship to these sonographic findings will be reviewed. CONCLUSION: The era of ultrasound markers as a screen for fetal aneuploidy is coming to a close. The detection of these markers on an ultrasound examination should simply serve as a reminder to ensure that the patient was offered cell-free DNA screening or conventional analyte screening. Cell-free DNA testing is revolutionizing screening. With normal results on a cell-free DNA test, many isolated soft markers-including CPCs, EIF, mild rhizomelic limb shortening, and mild pyelectasis-are irrelevant from a genetic standpoint. However, further counseling and workup are indicated for VM, true FEB, femur or humerus length measurement that is less than 2.5-percentile value, and pyelectasis to evaluate for the nongenetic associations with these findings. Finally, cell-free DNA testing is currently a screening test; positive results require definitive diagnostic testing with amniocentesis or chorionic villus sampling.

Obstetric and Gynecologic Ultrasound Curriculum and Competency Assessment in Residency Training Programs: Consensus Report.

Ultrasound imaging has become integral to the practice of obstetrics and gynecology. With increasing educational demands and limited hours in residency programs, dedicated time for training and achieving competency in ultrasound has diminished substantially. The American Institute of Ultrasound in Medicine assembled a multisociety task force to develop a consensus-based, standardized curriculum and competency assessment tools for obstetric and gynecologic ultrasound training in residency programs. The curriculum and competency assessment tools were developed based on existing national and international guidelines for the performance of obstetric and gynecologic ultrasound examinations and thus are intended to represent the minimum requirement for such training. By expert consensus, the curriculum was developed for each year of training, criteria for each competency assessment image were generated, the pass score was established at, or close to, 75% for each, and obtaining a set of 5 ultrasound images with pass score in each was deemed necessary for attaining each competency. Given the current lack of substantial data on competency assessment in ultrasound training, the task force expects that the criteria set forth in this document will evolve with time. The task force also encourages use of ultrasound simulation in residency training and expects that simulation will play a significant part in the curriculum and the competency assessment process. Incorporating this training curriculum and the competency assessment tools may promote consistency in training and competency assessment, thus enhancing the performance and diagnostic accuracy of ultrasound examination in obstetrics and gynecology.

Diagnostic cytogenetic testing following positive noninvasive prenatal screening results: a clinical laboratory practice resource of the American College of Medical Genetics and Genomics (ACMG).

Disclaimer: ACMG Clinical Laboratory Practice Resources are developed primarily as an educational tool for clinical laboratory geneticists to help them provide quality clinical laboratory genetic services. Adherence to these practice resources is voluntary and does not necessarily assure a successful medical outcome. This Clinical Laboratory Practice Resource should not be considered inclusive of all proper procedures and tests or exclusive of other procedures and tests that are reasonably directed to obtaining the same results. In determining the propriety of any specific procedure or test, the clinical laboratory geneticist should apply his or her own professional judgment to the specific circumstances presented by the individual patient or specimen. Clinical laboratory geneticists are encouraged to document in the patient's record the rationale for the use of a particular procedure or test, whether or not it is in conformance with this Clinical Laboratory Practice Resource. They also are advised to take notice of the date any particular guideline was adopted, and to consider other relevant medical and scientific information that becomes available after that date. It also would be prudent to consider whether intellectual property interests may restrict the performance of certain tests and other procedures.Noninvasive prenatal screening (NIPS) using cell-free DNA has been rapidly adopted into prenatal care. Since NIPS is a screening test, diagnostic testing is recommended to confirm all cases of screen-positive NIPS results. For cytogenetics laboratories performing confirmatory testing on prenatal diagnostic samples, a standardized testing algorithm is needed to ensure that the appropriate testing takes place. This algorithm includes diagnostic testing by either chorionic villi sampling or amniocentesis samples and encompasses chromosome analysis, fluorescence in situ hybridization, and chromosomal microarray.

Cell-free DNA, inflammation, and the initiation of spontaneous term labor.

BACKGROUND: Hypomethylated cell-free DNA from senescent placental trophoblasts may be involved in the activation of the inflammatory cascade to initiate labor. OBJECTIVE: To determine the changes in cell-free DNA concentrations, the methylation ratio, and inflammatory markers between women in labor at term vs women without labor. STUDY DESIGN: In this prospective cohort study, eligible participants carried a nonanomalous singleton fetus. Women with major medical comorbidity, preterm labor, progesterone use, aneuploidy, infectious disease, vaginal bleeding, abdominal trauma, or invasive procedures during the pregnancy were excluded. Maternal blood samples were collected at 28 weeks, 36 weeks, and at admission for delivery. Total cell-free DNA concentration, methylation ratio, and interleukin-6 were analyzed. The primary outcome was the difference in methylation ratio in women with labor vs without labor. Secondary outcomes included the longitudinal changes in these biomarkers corresponding to labor status. RESULTS: A total of 55 women were included; 20 presented in labor on admission and 35 presented without labor. Women in labor had significantly greater methylation ratio (P = .001) and interleukin-6 (P < .001) on admission for delivery than women without labor. After we controlled for body mass index and maternal age, methylation ratio (adjusted relative risk, 1.38; 95% confidence interval, 1.13 to 1.68) and interleukin-6 (adjusted relative risk, 1.12, 95% confidence interval, 1.07 to 1.17) remained greater in women presenting in labor. Total cell-free DNA was not significantly different in women with labor compared with women without. Longitudinally, total cell-free DNA (P < .001 in labor, P = .002 without labor) and interleukin-6 (P < .001 in labor, P = .01 without labor) increased significantly across gestation in both groups. The methylation ratio increased significantly in women with labor from 36 weeks to delivery (P = .02). CONCLUSION: Spontaneous labor at term is associated with a greater cell-free DNA methylation ratio and interleukin-6 compared with nonlabored controls. As gestation advances, total cell-free DNA concentrations and interleukin-6 levels increase. A greater methylation ratio reflects a greater maternal contribution (vs placental) in women with labor, likely resulting from greater levels of neutrophils, lymphocytes, and uterine activation proteins at the time of labor. Although not significant, women in labor had a greater total cell-free DNA concentration and thus could theoretically have more hypomethylated DNA available for interaction with the inflammatory cascade. Larger studies are needed to investigate this theory.

Experiences among Women with Positive Prenatal Expanded Carrier Screening Results.

The offering and acceptance of expanded carrier screening is increasing among pregnant women including women without an increased risk based on race, ethnicity or family history. The chances of a positive screening test have been reported to be as high as 24 % when multiple conditions are screened. Yet, little is known about the way these tests are offered and how patients are affected by a positive test result. To explore this area of genetic testing, interviews (n = 17) were conducted among women who received positive expanded carrier results in the context of obstetric care. A content analysis was conducted on the transcript data from the interviews. Outcomes of this research suggest that educational interventions are needed to improve maternal understanding of positive carrier screening results. Most of the participants in this study confused the results with other prenatal screening test options. In addition, the way the results were discussed varied greatly, and influenced participants' thoughts about reproductive decisions that led to a range of emotional uncertainty. Our data suggests that genetic counseling improved participants' understanding of positive results. More research is needed to further understand if our results are consistent within a larger, more diverse sample, and to explore how to best provide education about expanded carrier screening.

Genetic Screening and the Obese Gravida.

Obesity compromises all forms of genetic screening. Although the risk for fetal aneuploidy is not altered by obesity, the risk for significant birth defects is increased. Therefore, the obese gravida is at an increased risk of fetal malformations with a diminished ability to be screened effectively by all screening methods: ultrasound, traditional serum analyte screening, and cell-free DNA screening. This chapter outlines both the current options and limitations of screening in the obese gravida. The offering of screening and diagnostic testing should not be altered in obese women despite the compromises placed on accurate fetal assessment.

What parents want to know about the storage and use of residual newborn bloodspots.

Many state newborn screening programs retain residual newborn screening bloodspots for a variety of purposes including quality assurance, biomedical research, and forensic applications. This project was designed to determine the information that prospective parents want to know about this practice. Eleven focus groups were conducted in four states. Pregnant women and their partners and parents of young children (N = 128) were recruited from the general public. Focus group participants viewed two educational movies on newborn screening and DBS retention and use. Transcripts were analyzed with qualitative methods and the results were synthesized to identify key information items. We identified 14 categories of information from the focus groups that were synthesized into seven items prospective parents want to know about residual DBS. The items included details about storage, potential uses, risks and burdens, safeguards, anonymity, return of results, and parental choice. For those state programs that retain residual dried bloodspots, inclusion of the seven things parents want to know about residual dried bloodspots in educational materials may improve parental understanding, trust, and acceptance of the retention and use of stored bloodspots.

The impact of noninvasive fetal evaluation: its effect on education, training, and the maintenance of clinical competence in prenatal diagnosis.

PURPOSE OF REVIEW: To highlight the evolution of prenatal diagnosis from invasive procedures to noninvasive assessments and to describe the efforts to educate both trainees and experienced physicians via simulation techniques. RECENT FINDINGS: The rapid development of noninvasive serum analyte screening as well as molecular genetic and sonographic techniques to evaluate the fetus has altered our ability to both educate trainees as well as to maintain physician competence to perform invasive procedures. Simulation-based learning is being incorporated into medical training across a broad range of specialties, including obstetrics and gynecology. SUMMARY: Prenatal diagnosis procedures will continue to be necessary for direct fetal assessment but on a much more limited scale. It is possible that all trainees will not be able to become competent in amniocentesis and other even less common procedures. Furthermore, experienced physicians may lose competence, given the lack of available procedures for skill retention. Innovative methods of skill acquisition and maintenance may be required in the near future. Although long-term assessments of efficacy are currently lacking, the introduction of comprehensive, simulation-based curriculia has the potential to both educate trainees and help maintain physician competence.

The impact of utilization of early aneuploidy screening on amniocenteses available for training in obstetrics and fetal medicine.

OBJECTIVE: First-trimester aneuploidy screening has high detection rates and low false-positive rates. Their use as well as the implementation of non-invasive prenatal testing may affect specialty training in prenatal diagnosis procedures. STUDY DESIGN: Descriptive study of first-trimester aneuploidy screening and amniocentesis in an obstetric training program. Screening methods were tracked from their introduction in 2004 through 2011. The volume of amniocentesis procedures from 2000 to 2011 was evaluated. RESULTS: First-trimester screening tests increased from 283 to 1225 between 2005 and 2011, whereas genetic amniocenteses declined from 460 to 168 during the same period. The percent of older women who chose a first-trimester screen test rose from 12.7% to 44.2% CONCLUSION: First-trimester screening options reduce genetic amniocenteses available for training. Fetal medicine and general obstetrics training programs need to evaluate their clinical experience and determine whether simulation training methods are needed for education.