Genes Implicated in Rare Congenital Inner Ear and Cochleovestibular Nerve Malformations.
Elina Kari, Lorida Llaci, John L Go and 8 others
PMID 31985533WHAT IT FOUND
Rare DNA variants in candidate genes were found in some children with absent or small cochleovestibular nerves, but not in four families.
Device outcomes varied, so these genes are not yet usable predictors.
Key findings
01Whole-exome sequencing in 12 families found rare candidate variants in some children with abnormal cochleovestibular nerves, but no compelling variants were found in four families.
02Rare candidate variants were identified in RIF1, HSPG2, TAF1, GREB1L, MASP1, and SIX1.
03Device outcomes varied across hearing aids, cochlear implants, and auditory brainstem implants, including no responses to hearing aids, no benefit from a cochlear implant, no benefit from both a cochlear implant and an auditory brainstem implant, moderate thresholds after a cochlear implant, mild thresholds on a cochlear implant ear with a hearing aid on the other ear, and unknown outcomes after an auditory brainstem implant.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study describes 12 families and does not provide prospective evidence that the identified variants predict hearing device outcomes. Four families had no compelling candidate variants, so the genetic cause was not found for all children. Some children had unknown outcomes after auditory brainstem implantation, so the paper cannot describe the full device course for every child. For three families, DNA was available from only one unaffected parent, which limits the inheritance analysis. Some children had major developmental, motor, balance, or feeding problems, and the extent of cognitive delays was not known for a child. The variants were rare, conserved, and predicted damaging, but the paper does not prove they caused the inner ear or nerve malformations. Four previously reported families were included, so some findings come from earlier reports.
Declared interests
The funding and conflicts section states that the authors have no conflicts of interest to disclose.
The easy way to misread this
Do not conclude that genetic testing can now predict cochlear implant benefit in children with abnormal cochleovestibular nerves. The study is descriptive, four families had no candidate variants, and the authors state the data are preliminary and need prospective research.