Guidelines for Audiologists on the Benefits and Limitations of Genetic Testing

Abstract

Audiologists are in a unique position to facilitate investigation into the etiology of a patient's hearing loss. This is of high importance in genetic etiologies because the diagnosis can provide information on recurrence risks and other potential health implications. Suggestions are made to help audiologists recognize when a genetics referral is warranted, counsel patients and their parents about the benefits and limitations of genetic testing, and interpret genetic test results.

Detailed Audiological Evaluation of a Patient with Xeroderma Pigmentosum with Neural Degeneration

“…Inclusion of early, middle, and late evoked potentials may be useful in assessment of these patients, though insufficient data exist to make this determination. Our case demonstrates the value of the audiologist in the facilitation of an accurate diagnosis through referral of patients with unusual clinical findings to geneticists, as appropriate (Mercer, 2015). Hearing loss is part of the clinical presentation in over 400 genetic syndromes (Angeli et al, 2012), including XP with neural degeneration and CMT.…”

Delayed diagnosis of a patient with Usher syndrome 1C in a Louisiana Acadian family highlights the necessity of timely genetic testing for the diagnosis and management of congenital hearing loss

“…In addition, related individuals with the exact same genetic mutation may express reduced penetrance or variable expressivity. 1 …”

“…In the United States, about 3–4/1000 children are born with complete sensorineural hearing loss (SNHL), with 50%–80% of cases due to genetic mutations. 1 Although genetic testing for hearing loss has been available since the 1990s, more recent advancements in DNA sequencing technology (next-generation sequencing) and diagnostic panels have become increasingly reliable and less expensive for clinical use. 2 , 3 Despite these developments, the diagnosis of genetic SNHL still presents challenges for healthcare providers.…”

“… 4 , 5 Another complication is that some genetic forms of SNHL demonstrate variable expressivity, in which the same genetic mutation can cause a different phenotype in two different patients, even within the same family. 1 …”

“…In the remaining 70% of these individuals, the SNHL is the only clinical presentation (non-syndromic hearing loss). 1 , 2 , 6 , 7 An early diagnosis is vital for proper management and care, as some clinical manifestations of syndromic SNHL are not apparent at birth and have a delayed age of onset. 6 Identifying the cause of deafness can benefit patients and their families by allowing clinicians to offer the proper interventions to improve patient quality of life as well as an estimate of recurrence risks for future family planning.…”