PurposeAutosomal recessive non-syndromic deafness (ARNSD) is characterized by a high degree of genetic heterogeneity with reported mutations in 58 different genes. This study was designed to detect deafness causing variants in a multiethnic cohort with ARNSD by using whole-exome sequencing (WES).MethodsAfter excluding mutations in the most common gene, GJB2, we performed WES in 160 multiplex families with ARNSD from Turkey, Iran, Mexico, Ecuador and Puerto Rico to screen for mutations in all known ARNSD genes.ResultsWe detected ARNSD-causing variants in 90 (56%) families, 54% of which had not been previously reported. Identified mutations were located in 31 known ARNSD genes. The most common genes with mutations were MYO15A (13%), MYO7A (11%), SLC26A4 (10%), TMPRSS3 (9%), TMC1 (8%), ILDR1 (6%) and CDH23 (4%). Nine mutations were detected in multiple families with shared haplotypes suggesting founder effects.ConclusionWe report on a large multiethnic cohort with ARNSD in which comprehensive analysis of all known ARNSD genes identifies causative DNA variants in 56% of the families. In the remaining families, WES allows us to search for causative variants in novel genes, thus improving our ability to explain the underlying etiology in more families.

Supernumerary teeth (ST) are odontostomatologic anomaly characterized by as the existence excessive number of teeth in relation to the normal dental formula. This condition is commonly seen with several congenital genetic disorders such as Gardner's syndrome, cleidocranial dysostosis and cleft lip and palate. Less common syndromes that are associated with ST are; Fabry Disease, Ellis-van Creveld syndrome, Nance-Horan syndrome, Rubinstein-Taybi Syndrome and Trico–Rhino–Phalangeal syndrome. ST can be an important component of a distinctive disorder and an important clue for early diagnosis. Certainly early detecting the abnormalities gives us to make correct management of the patient and also it is important for making well-informed decisions about long-term medical care and treatment. In this review, the genetic syndromes that are related with ST were discussed.

BackgroundMutations in the POU3F4 gene cause X-linked deafness type 3 (DFN3), which is characterized by inner ear anomalies.MethodsThree Turkish, one Ecuadorian, and one Nigerian families were included based on either inner ear anomalies detected in probands or X-linked family histories. Exome sequencing and/or Sanger sequencing were performed in order to identify the causative DNA variants in these families.ResultsFour novel, c.707A>C (p.(Glu236Ala)), c.772delG (p.(Glu258ArgfsX30)), c.902C>T (p.(Pro301Leu)), c.987T>C (p.(Ile308Thr)), and one previously reported mutation c.346delG (p.(Ala116ProfsX26)) in POU3F4, were identified. All mutations identified are predicted to affect the POU-specific or POU homeo domains of the protein and co-segregated with deafness in all families.ConclusionsExpanding the spectrum of POU3F4 mutations in different populations along with their associated phenotypes provides better understanding of their clinical importance and will be helpful in clinical evaluation and counseling of the affected individuals.Electronic supplementary materialThe online version of this article (doi:10.1186/s12881-015-0149-2) contains supplementary material, which is available to authorized users.