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Lo E, Blair J, Yamamoto N, Diaz-Miranda MA, Bedoukian E, Gray C, Lawrence A, Dedhia K, Elden LM, Germiller JA, Kazahaya K, Sobol SE, Luo M, Krantz ID, Hartman TR. Recurrent missense variant identified in two unrelated families with MPZL2-related hearing loss, expanding the variant spectrum associated with DFNB111. Am J Med Genet A 2024; 194:e63530. [PMID: 38197511 DOI: 10.1002/ajmg.a.63530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/17/2023] [Accepted: 12/22/2023] [Indexed: 01/11/2024]
Abstract
MPZL2-related hearing loss is a rare form of autosomal recessive hearing loss characterized by progressive, mild sloping to severe sensorineural hearing loss. Thirty-five previously reported patients had biallelic truncating variants in MPZL2, with the exception of one patient with a missense variant of uncertain significance and a truncating variant. Here, we describe the clinical characteristics and genotypes of five patients from four families with confirmed MPZL2-related hearing loss. A rare missense likely pathogenic variant [NM_005797.4(MPZL2):c.280C>T,p.(Arg94Trp)] located in exon 3 was confirmed to be in trans with a recurrent pathogenic truncating variant that segregated with hearing loss in three of the patients from two unrelated families. This is the first recurrent likely pathogenic missense variant identified in MPZL2. Apparently milder or later-onset hearing loss associated with rare missense variants in MPZL2 indicates that some missense variants in this gene may cause a milder phenotype than that resulting from homozygous or compound heterozygous truncating variants. This study, along with the identification of truncating loss of function and missense MPZL2 variants in several diverse populations, suggests that MPZL2-related hearing loss may be more common than previously appreciated and demonstrates the need for MPZL2 inclusion in hearing loss testing panels.
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Affiliation(s)
- Emma Lo
- Roberts Individualized Medical Genetics Center (RIMGC), Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Justin Blair
- Roberts Individualized Medical Genetics Center (RIMGC), Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Nobuko Yamamoto
- Roberts Individualized Medical Genetics Center (RIMGC), Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Otolaryngology, Department of Surgical Specialties, National Center for Children's Health and Development, Tokyo, Japan
| | - Maria Alejandra Diaz-Miranda
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Emma Bedoukian
- Roberts Individualized Medical Genetics Center (RIMGC), Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Christopher Gray
- Roberts Individualized Medical Genetics Center (RIMGC), Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Audrey Lawrence
- Roberts Individualized Medical Genetics Center (RIMGC), Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Kavita Dedhia
- Division of Otolaryngology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology - Head and Neck Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Lisa M Elden
- Division of Otolaryngology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology - Head and Neck Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John A Germiller
- Division of Otolaryngology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology - Head and Neck Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ken Kazahaya
- Division of Otolaryngology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology - Head and Neck Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Steven E Sobol
- Division of Otolaryngology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Otorhinolaryngology - Head and Neck Surgery, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Minjie Luo
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ian D Krantz
- Roberts Individualized Medical Genetics Center (RIMGC), Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Tiffiney R Hartman
- Roberts Individualized Medical Genetics Center (RIMGC), Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Translational Medicine and Human Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
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