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Hearing loss affects 1 to 3 per 1000 infants born in the United States. More than half of early childhood hearing loss has a genetic etiology. Rapid advances in gene discovery and mutation identification have revealed extensive genetic heterogeneity.1 Recognizing the need for comprehensive continuing education in this fast moving area of clinical and molecular genetics, a slide set on early childhood hearing loss was developed under the direction of the ACMG Education and CME committee in 2000. Quickly outdated by the continuing accomplishments in the field, the original slide set was revised in early 2002 by a six-member working group, with comments from a four-member review panel and the Education and CME committee of the ACMG. The revised slide set was approved by the ACMG Board of Directors in January 2003.

This newly revised slide set is intended as an educational resource for both self-directed learning and in support of medical genetics teaching activities.1 As a self-directed learning tool, it provides comprehensive coverage of the clinical and molecular genetic aspects of hearing loss, complete with references and resources for further study. As a resource for teaching activities, it includes talking points for speakers and teaching tools such as learning objectives (Table 1), sample review questions (Table 2), and a content outline (Table 3).

Table 1 Learning objectives
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Table 2 Slide set review questions
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Table 3 Slide set content outline
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The charge and mission of the Education and CME committee of the ACMG includes a responsibility to “plan, organize and conduct various educational activities of the College.” The development of this slide set supports this educational mission. It is the first in a series of educational slide sets planned by the ACMG. At the present time, the College does not plan to offer credit for review of the slide set.

Format

The slide set is produced in Microsoft PowerPoint 2002 and is available on CD. The CD is compatible with both Mac and PC platforms. The CD is programmed to auto-launch the slide set in the Notes Page View format of PowerPoint. Additional instructions for manually launching the program are provided on the back of the CD’s cover sleeve. The notes sections of the slides can also be accessed manually, by selecting “View” and “Notes Page” from the top menu bar of PowerPoint. System requirements for running the CD are as follows: PC—Windows 98 or greater, Microsoft PowerPoint 97 or greater; Macintosh—OS 9 or greater, Microsoft PowerPoint 97 or greater. The slide set contains 68 slides and is extensively illustrated with diagrams, images, and photographs. Due to its comprehensive content and numerous illustrations, the size of the PowerPoint file is ≈20 megabytes.

Background material for each slide is provided in the Notes Page View format of PowerPoint. It includes learning objectives (Table 1), review questions (Table 2) with answers and explanations, a content outline (Table 3), explanations of each slide, detailed descriptions of the clinical and scientific content, figure legends, talking points for speakers who use the slides in teaching activities, citations for images, funding sources, suggested reading, and references.

When the slide set is used in teaching presentations, users can select “View” and “Slide Show” from the top menu bar of PowerPoint, or click on the slide show icon in the lower menu bar of PowerPoint. This will launch the slide show presentation, hiding the notes sections of the slides, and showing only the presentation content of the slides.

Content

Focused primarily on early childhood hearing loss, the slide set contains a comprehensive review of genetic hearing loss, highlights its extreme etiologic and phenotypic heterogeneity, and includes a discussion of genetic forms of hearing loss characterized by later onset.

The slide set opens with introductory materials including the title slide, recognition of the working group and reviewers, and a legal statement slide. The notes sections of these slides contain the learning objectives (Table 1), review questions (Table 2), and content outline (Table 3).

The slide set continues with an idealized case (Fig. 1 and Table 4), an introduction to the biomechanics of hearing, and a description of the basic tools of audiology. The incidence and etiologies of early childhood hearing loss are described, as are the various patterns of inheritance of genetic traits and conditions.

Fig. 1
figure 1

Case presentation. Idealized click ABR evaluation for a child with moderate to severe sensorineural hearing loss. X-axis shows the decibels (dB) normed to hearing level. Y-axis shows the Wave V Latency in milliseconds. The gray area delineates normal ranges. Wave V latency was not obtained below 50 dB (decibels). Response to 500-Hz tone burst occurred at 50 dB. No response to tone burst at 8000 Hz was obtained. Bone and air conduction thresholds were matching, indicating a sensorineural hearing loss. The 50-dB click threshold indicates a moderate to severe hearing loss.

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Table 4 Case presentation
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Several common forms of syndromic hearing loss and their genetic bases are highlighted including branchio-oto-renal (BOR) syndrome, Waardenburg syndrome, Pendred syndrome, Jervell and Lange-Nielsen syndrome (JLNS), Alport syndrome, and Usher syndrome, among others. The genes known to be associated with nonsyndromic hearing loss are delineated and a description of Internet resources for additional information and continued learning is provided.

The most common cause of nonsyndromic genetic hearing loss, mutations in the gene GJB2, encoding Connexin 26, is explored. The slides describe gap junction channel function and provide a possible explanation of GJB2-based hearing loss. The frequency of GJB2-based hearing loss and a summary of common genetic mutations in GJB2 are also discussed.

ACMG statements and guidelines on newborn screening for hearing loss and the etiologic diagnosis of congenital hearing loss are reiterated, highlighting the clinical applications of knowledge about the molecular genetics of hearing loss.2,3 Also included are descriptions of the role of clinical genetics and genetic counseling in evaluation and care of patients with hearing loss and other genetic disorders, the potential benefits of clinical genetics consultation, resources for the identification and utilization of clinical genetics services, the capabilities, limitations, benefits and risks of genetic testing, and mechanisms for identifying and utilizing laboratory genetics services.

In the conclusion slides, the case presented earlier (Fig. 1 and Table 4) is resolved through the presentation of DNA test results, with interpretation of the results, their implications, and limitations. Additional resources for information and continuing education are provided, as is a series of summary slides. Acknowledgments, additional online resources, suggested reading, references, and answers to review questions are found in the notes sections of these final slides.

Availability

The slide set is available through the Web site of the American College of Medical Genetics: http://www.acmg.net. The slide set is offered for $20, plus $5 shipping and handling ($10 shipping and handling for overseas or express rate shipping) and applicable sales tax.

Four sample slides, in Notes Page View Format, are available via the ArticlePlus feature at the Web site of the journal Genetics in Medicine, 2003: http://www.geneticsinmedicine.org

Future ACMG slide sets

Working groups are assembled to develop additional educational slide sets in a format similar to this one. Slide sets are planned on cystic fibrosis, newborn screening, and the genetics of cardiovascular disease. Suggestions on topics for future slide sets are welcome and can be directed to Raye Lynn Alford, PhD, FACMG, Chair of the 2003 ACMG Education and CME committee.