A Start Codon Variant in NOG Underlies Symphalangism and Ossicular Chain Malformations Affecting Both the Incus and the Stapes

We performed exome sequencing to evaluate the underlying molecular cause of a patient with bilateral conductive hearing loss due to multiple ossicular abnormalities as well as symphalangism of the fifth digits. This leads to the identification of a novel heterozygous start codon variant in the NOG g...

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Main Authors: Nathan R. Lindquist, Eric N. Appelbaum, Anushree Acharya, Jeffrey T. Vrabec, Suzanne M. Leal, Isabelle Schrauwen
Format: Article
Language:English
Published: Wiley 2019-01-01
Series:Case Reports in Genetics
Online Access:http://dx.doi.org/10.1155/2019/2836263
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author Nathan R. Lindquist
Eric N. Appelbaum
Anushree Acharya
Jeffrey T. Vrabec
Suzanne M. Leal
Isabelle Schrauwen
author_facet Nathan R. Lindquist
Eric N. Appelbaum
Anushree Acharya
Jeffrey T. Vrabec
Suzanne M. Leal
Isabelle Schrauwen
author_sort Nathan R. Lindquist
collection DOAJ
description We performed exome sequencing to evaluate the underlying molecular cause of a patient with bilateral conductive hearing loss due to multiple ossicular abnormalities as well as symphalangism of the fifth digits. This leads to the identification of a novel heterozygous start codon variant in the NOG gene (c.2T>C:p.Met1?) that hinders normal translation of the noggin protein. Variants in NOG lead to a spectrum of otologic, digit, and joint abnormalities, a combination suggested to be referred to as NOG‐related‐symphalangism spectrum disorder (NOG‐SSD). Conductive hearing loss from such variants may stem from stapes footplate ankylosis, fixation of the malleoincudal joint, or fixation of the incus short process. In this case, the constellation of both stapes and incus fixation, an exceptionally tall stapes suprastructure, thickened long process of the incus, and enlarged incus body was encountered, leading to distinct challenges during otologic surgery to improve hearing thresholds. This case highlights multiple abnormalities to the ossicular chain in a patient with a start codon variant in NOG. We provide detailed imaging data on these malformations as well as surgical considerations and outcomes.
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spelling doaj-art-c6bd20ce8e624abaa3450bca26103da52025-08-20T03:23:19ZengWileyCase Reports in Genetics2090-65442090-65522019-01-01201910.1155/2019/28362632836263A Start Codon Variant in NOG Underlies Symphalangism and Ossicular Chain Malformations Affecting Both the Incus and the StapesNathan R. Lindquist0Eric N. Appelbaum1Anushree Acharya2Jeffrey T. Vrabec3Suzanne M. Leal4Isabelle Schrauwen5Department of Otolaryngology, Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, USADepartment of Otolaryngology, Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, USACenter for Statistical Genetics, Department of Neurology, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USADepartment of Otolaryngology, Houston Methodist Hospital, Houston, Texas, USACenter for Statistical Genetics, Department of Neurology, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USACenter for Statistical Genetics, Department of Neurology, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USAWe performed exome sequencing to evaluate the underlying molecular cause of a patient with bilateral conductive hearing loss due to multiple ossicular abnormalities as well as symphalangism of the fifth digits. This leads to the identification of a novel heterozygous start codon variant in the NOG gene (c.2T>C:p.Met1?) that hinders normal translation of the noggin protein. Variants in NOG lead to a spectrum of otologic, digit, and joint abnormalities, a combination suggested to be referred to as NOG‐related‐symphalangism spectrum disorder (NOG‐SSD). Conductive hearing loss from such variants may stem from stapes footplate ankylosis, fixation of the malleoincudal joint, or fixation of the incus short process. In this case, the constellation of both stapes and incus fixation, an exceptionally tall stapes suprastructure, thickened long process of the incus, and enlarged incus body was encountered, leading to distinct challenges during otologic surgery to improve hearing thresholds. This case highlights multiple abnormalities to the ossicular chain in a patient with a start codon variant in NOG. We provide detailed imaging data on these malformations as well as surgical considerations and outcomes.http://dx.doi.org/10.1155/2019/2836263
spellingShingle Nathan R. Lindquist
Eric N. Appelbaum
Anushree Acharya
Jeffrey T. Vrabec
Suzanne M. Leal
Isabelle Schrauwen
A Start Codon Variant in NOG Underlies Symphalangism and Ossicular Chain Malformations Affecting Both the Incus and the Stapes
Case Reports in Genetics
title A Start Codon Variant in NOG Underlies Symphalangism and Ossicular Chain Malformations Affecting Both the Incus and the Stapes
title_full A Start Codon Variant in NOG Underlies Symphalangism and Ossicular Chain Malformations Affecting Both the Incus and the Stapes
title_fullStr A Start Codon Variant in NOG Underlies Symphalangism and Ossicular Chain Malformations Affecting Both the Incus and the Stapes
title_full_unstemmed A Start Codon Variant in NOG Underlies Symphalangism and Ossicular Chain Malformations Affecting Both the Incus and the Stapes
title_short A Start Codon Variant in NOG Underlies Symphalangism and Ossicular Chain Malformations Affecting Both the Incus and the Stapes
title_sort start codon variant in nog underlies symphalangism and ossicular chain malformations affecting both the incus and the stapes
url http://dx.doi.org/10.1155/2019/2836263
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