Mutations in SLC26A4 cause nonsyndromic hearing loss associated with an enlarged vestibular aqueduct (EVA, also known as DFNB4) and Pendred syndrome (PS), the most common type of autosomal-recessive syndromic deafness. In many patients with an EVA/PS phenotype, mutation screening of SLC26A4 fails to identify two disease-causing allele variants. That a sizable fraction of patients carry only one SLC26A4 mutation suggests that EVA/PS is a complex disease involving other genetic factors. Here, we show that mutations in the inwardly rectifying K(+) channel gene KCNJ10 are associated with nonsyndromic hearing loss in carriers of SLC26A4 mutations with an EVA/PS phenotype. In probands from two families, we identified double heterozygosity in affected individuals. These persons carried single mutations in both SLC26A4 and KCNJ10. The identified SLC26A4 mutations have been previously implicated in EVA/PS, and the KCNJ10 mutations reduce K(+) conductance activity, which is critical for generating and maintaining the endocochlear potential. In addition, we show that haploinsufficiency of Slc26a4 in the Slc26a4(+/-) mouse mutant results in reduced protein expression of Kcnj10 in the stria vascularis of the inner ear. Our results link KCNJ10 mutations with EVA/PS and provide further support for the model of EVA/PS as a multigenic complex disease.

We conducted an exploratory study of the experiences of genetic counselors who have either trained or supervised in a second language to assess the relevance of this issue to genetic counseling training and supervision. Two hundred-thirty NSGC members, CAGC members and genetic counseling students completed the online questionnaire. Many of the respondents reported that training and supervision differed when another language was involved. Supervisors reported difficulty in assessing students' counseling skills and discomfort with an incomplete understanding of session content. Students described a greater focus on vocabulary at the expense of psychosocial dimensions. Despite this, most felt that using another language enhanced their training experience. As such, training programs might consider increasing support to these learners and supervisors by explicitly acknowledging the challenges they face, providing students with language tools to aid in their acquisition of basic skills and providing supervisors with new methods for assessing student counseling skills when using other languages.

Due to a production error, the following text was erroneously changed from the original text. The corrections are as follows: & On page 3, in the 2nd paragraph under the subhead Instrumentation, where it says "Purpose of the Study" it should read "Section 1 of the questionnaire." In the same paragraph, where it says "Methods," it should read "Section 2 of the questionnaire." And where it says "Results," it should read "section 3 of the questionnaire." & On page 5, in the first sentence under the subhead Students' Responses, "Purpose of the Study " and "Methods" should read "Sections 1 and 2." & Additionally, on page 5, in the first sentence under the header Quantitative Analysis of Supervisors' Responses to Close-Ended Questions, where it says "Results" it should read "section 3." Springer regrets the errors.

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