De novo variants in GREB1L are associated with non-syndromic inner ear malformations and deafness.

Congenital inner ear malformations affecting both the osseous and membranous labyrinth can have a devastating impact on hearing and language development. With the exception of an enlarged vestibular aqueduct, non-syndromic inner ear malformations are rare, and their underlying molecular biology has thus far remained understudied. To identify molecular factors that might be important in the developing inner ear, we adopted a family-based trio exome sequencing approach in young unrelated subjects with severe inner ear malformations. We identified two previously unreported de novo loss-of-function variants in GREB1L [c.4368G>T;p.(Glu1410fs) and c.982C>T;p.(Arg328*)] in two affected subjects with absent cochleae and eighth cranial nerve malformations. The cochlear aplasia in these affected subjects suggests that a developmental arrest or problem at a very early stage of inner ear development exists, e.g., during the otic pit formation. Craniofacial Greb1l RNA expression peaks in mice during this time frame (E8.5). It also peaks in the developing inner ear during E13-E16, after which it decreases in adulthood. The crucial function of Greb1l in craniofacial development is also evidenced in knockout mice, which develop severe craniofacial abnormalities. In addition, we show that Greb1l-/- zebrafish exhibit a loss of abnormal sensory epithelia innervation. An important role for Greb1l in sensory epithelia innervation development is supported by the eighth cranial nerve deficiencies seen in both affected subjects. In conclusion, we demonstrate that GREB1L is a key player in early inner ear and eighth cranial nerve development. Abnormalities in cochleovestibular anatomy can provide challenges for cochlear implantation. Combining a molecular diagnosis with imaging techniques might aid the development of individually tailored therapeutic interventions in the future.

Oritavancin: A Novel Lipoglycopeptide.

OBJECTIVE: To review the pharmacology, pharmacokinetics, drug interactions, microbiologic profile, dosage and administration, safety, clinical efficacy, and potential place in therapy for the new lipoglycopetide, oritavancin. DATA SOURCES: MEDLINE and PubMed searches of available literature in English were conducted for oritavancin. Principal supplementary sources include the Food and Drug Administration (FDA) package insert, and FDA/European Medicines Agency guidances on acute bacterial skin and skin structure infections (ABSSSI). STUDY SELECTION AND DATA EXTRACTION: Information from all stages of clinical development was evaluated to provide an overview of oritavancin, from in vitro susceptibility, to early human studies, to the latter stages of clinical trials. DATA SYNTHESIS: Oritavancin is a lipoglycopeptide antibiotic that has a mechanism of action and broad-spectrum gram-positive coverage similar to other glycopeptides. Compared with other glycopeptides, oritavancin minimum inhibitory concentrations tend to be lower. Oritavancin also has coverage against glycopeptide-resistant gram-positive organisms. Oritavancin does not require dose adjustment for mild-to-moderate hepatic or renal impairment, and its prolonged half-life of 245 hours allows for a one-time administration in the treatment of ABSSSI. In phase 2 and 3 clinical trials, oritavancin was shown to be well-tolerated in addition to being noninferior to vancomycin for the treatment of ABSSSI. The most common side effects experienced were gastrointestinal in nature. CONCLUSIONS: Oritavancin was approved by FDA for the treatment of ABSSSI in August 2014 and is marketed under the trade name Orbactiv. Its reduced dosing and monitoring requirements and efficacy against resistant gram-positive pathogens provide a unique profile that distinguishes it from current options in the treatment of ABSSSI.