1
|
Wang P, Wu P, Wang J, Zeng Y, Jiang Y, Wang Y, Li S, Xiao X, Zhang Q. Missense Mutations in MAB21L1: Causation of Novel Autosomal Dominant Ocular BAMD Syndrome. Invest Ophthalmol Vis Sci 2023; 64:19. [PMID: 36892533 PMCID: PMC10010443 DOI: 10.1167/iovs.64.3.19] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023] Open
Abstract
Purpose Biallelic MAB21L1 variants have been reported to cause autosomal recessive cerebellar, ocular, craniofacial, and genital syndrome (COFG), whereas only five heterozygous pathogenic variants have been suspected to cause autosomal dominant (AD) microphthalmia and aniridia in eight families. This study aimed to report an AD ocular syndrome (blepharophimosis plus anterior segment and macular dysgenesis [BAMD]) syndrome based on clinical and genetic findings from patients with monoallelic MAB21L1 pathogenic variants in our cohort and reported cases. Methods Potential pathogenic variants in MAB21L1 were detected from a large in-house exome sequencing dataset. Ocular phenotypes of the patients with potential pathogenic variants in MAB21L1 were summarized, and the genotype-phenotype correlation was analyzed through a comprehensive literature review. Results Three heterozygous missense variants in MAB21L1, predicted to be damaging, were detected in 5 unrelated families, including c.152G>T in 2, c.152G>A in 2, and c.155T>G in one. All were absent from gnomAD. The variants were de novo in two families, transmitted from affected parents to offspring in two families, and with an unknown origin in the other family, demonstrating strong evidence of AD inheritance. All patients revealed similar BAMD phenotypes, including blepharophimosis, anterior segment dysgenesis, and macular dysgenesis. Genotype-phenotype analysis suggested that patients with monoallelic MAB21L1 missense variants had only ocular anomalies (BAMD), whereas patients with biallelic variants presented both ocular and extraocular symptoms. Conclusions Heterozygous pathogenic variants in MAB21L1 account for a new AD BAMD syndrome, which is completely different from COFG caused by homozygous variants in MAB21L1. Nucleotide c.152 is likely a mutation hot spot, and the encoded residue of p.Arg51 might be critical for MAB21L1.
Collapse
Affiliation(s)
- Panfeng Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Pengsen Wu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Junwen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yiyan Zeng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yi Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yingwei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| |
Collapse
|
2
|
Meng F, Li X, Zhang J, Gao Z, Yang X, Liu Z, Liu Y, Guo T, Wang L, Yang L, Wang Z. Single amino acid variation in MAB21L1 is dominantly associated with congenital eye defects. J Med Genet 2022:jmg-2022-108506. [DOI: 10.1136/jmg-2022-108506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 10/19/2022] [Indexed: 11/30/2022]
Abstract
BackgroundDiagnosis of a genetic disease and determination of the causative molecular lesion rely on the availability of the disease-associated pedigrees. Microphthalmia is a congenital eye defect due to an insufficiently developed visual system; its prevalence is 1–3 in 10 000 live births.ObjectiveWe analysed a pedigree exhibiting autosomal dominant inheritance of microphthalmia to determine the genetic lesion; used AlphaFold2 to predict the changes in the protein’s 3-Dimensional structure; and compared wild-type and variant proteins in cultured cells or Drosophila model was used to explore the cellular or developmental function of the encoded product.ResultsWe identified a novel missense variation, F52L, in MAB21L1 that is absent in population databases and present exclusively in the individuals diagnosed with microphthalmia in this pedigree. Common structural changes were predicted for the disease-associated variants clustered at amino acids 49–52, and these variant products were also predominantly trapped in the cytoplasm of cultured human lens epithelia. To recapitulate its dominant effect in development, we expressed the Drosophila homologue corresponding to MAB21L1F52Land caused malformation of sensory organs.ConclusionMutations at the residues 49–52 of MAB21L1 compromise eye development. We recommend includingMAB21L1in the genetic testing panel for congenital eye disorders.
Collapse
|
3
|
Hall HN, Bengani H, Hufnagel RB, Damante G, Ansari M, Marsh JA, Grimes GR, von Kriegsheim A, Moore D, McKie L, Rahmat J, Mio C, Blyth M, Keng WT, Islam L, McEntargart M, Mannens MM, Heyningen VV, Rainger J, Brooks BP, FitzPatrick DR. Monoallelic variants resulting in substitutions of MAB21L1 Arg51 Cause Aniridia and microphthalmia. PLoS One 2022; 17:e0268149. [PMID: 36413568 PMCID: PMC9681113 DOI: 10.1371/journal.pone.0268149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 10/06/2022] [Indexed: 11/23/2022] Open
Abstract
Classical aniridia is a congenital and progressive panocular disorder almost exclusively caused by heterozygous loss-of-function variants at the PAX6 locus. We report nine individuals from five families with severe aniridia and/or microphthalmia (with no detectable PAX6 mutation) with ultrarare monoallelic missense variants altering the Arg51 codon of MAB21L1. These mutations occurred de novo in 3/5 families, with the remaining families being compatible with autosomal dominant inheritance. Mice engineered to carry the p.Arg51Leu change showed a highly-penetrant optic disc anomaly in heterozygous animals with severe microphthalmia in homozygotes. Substitutions of the same codon (Arg51) in MAB21L2, a close homolog of MAB21L1, cause severe ocular and skeletal malformations in humans and mice. The predicted nucleotidyltransferase function of MAB21L1 could not be demonstrated using purified protein with a variety of nucleotide substrates and oligonucleotide activators. Induced expression of GFP-tagged wildtype and mutant MAB21L1 in human cells caused only modest transcriptional changes. Mass spectrometry of immunoprecipitated protein revealed that both mutant and wildtype MAB21L1 associate with transcription factors that are known regulators of PAX6 (MEIS1, MEIS2 and PBX1) and with poly(A) RNA binding proteins. Arg51 substitutions reduce the association of wild-type MAB21L1 with TBL1XR1, a component of the NCoR complex. We found limited evidence for mutation-specific interactions with MSI2/Musashi-2, an RNA-binding proteins with effects on many different developmental pathways. Given that biallelic loss-of-function variants in MAB21L1 result in a milder eye phenotype we suggest that Arg51-altering monoallelic variants most plausibly perturb eye development via a gain-of-function mechanism.
Collapse
Affiliation(s)
- Hildegard Nikki Hall
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Hemant Bengani
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Robert B. Hufnagel
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States of America
| | | | - Morad Ansari
- South East Scotland Genetic Service, Western General Hospital, Edinburgh, United Kingdom
| | - Joseph A. Marsh
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Graeme R. Grimes
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Alex von Kriegsheim
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - David Moore
- South East Scotland Genetic Service, Western General Hospital, Edinburgh, United Kingdom
| | - Lisa McKie
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Jamalia Rahmat
- Ophthalmology Department, Hospital Kuala Lumpur, Kuala Lumpur, Malaysia
| | - Catia Mio
- Department of Medicine, University of Udine, Udine, Italy
| | - Moira Blyth
- University of Leeds, St. James’s University Hospital, Leeds, United Kingdom
| | - Wee Teik Keng
- Department of Genetics, Kuala Lumpur Hospital, Kuala Lumpur, Malaysia
| | - Lily Islam
- West Midlands Regional Genetics Service, Birmingham Women’s and Children’s NHS Foundation Trust, Birmingham, England
| | - Meriel McEntargart
- Medical Genetics, St George’s University Hospitals NHS Foundation Trust, London, United Kingdom
| | - Marcel M. Mannens
- Genome Diagnostics laboratory, Department of Clinical Genetics, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Veronica Van Heyningen
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Joe Rainger
- Roslin Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Brian P. Brooks
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States of America
| | - David R. FitzPatrick
- MRC Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| |
Collapse
|
4
|
Seese SE, Reis LM, Deml B, Griffith C, Reich A, Jamieson RV, Semina EV. Identification of missense MAB21L1 variants in microphthalmia and aniridia. Hum Mutat 2021; 42:877-890. [PMID: 33973683 PMCID: PMC8238893 DOI: 10.1002/humu.24218] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/29/2021] [Accepted: 04/27/2021] [Indexed: 12/14/2022]
Abstract
Microphthalmia, coloboma, and aniridia are congenital ocular phenotypes with a strong genetic component but often unknown cause. We present a likely causative novel variant in MAB21L1, c.152G>T p.(Arg51Leu), in two family members with microphthalmia and aniridia, as well as novel or rare compound heterozygous variants of uncertain significance, c.184C>T p.(Arg62Cys)/c.-68T>C, and c.658G>C p.(Gly220Arg)/c.*529A>G, in two additional probands with microphthalmia, coloboma and/or cataracts. All variants were predicted as damaging by in silico programs. In vitro studies of coding variants revealed normal subcellular localization but variable stability for the corresponding mutant proteins. In vivo complementation assays using the zebrafish mab21l2 Q48Sfs*5 loss-of-function line demonstrated that though overexpression of wild-type MAB21L1 messenger RNA (mRNA) compensated for the loss of mab21l2, none of the coding variant mRNAs produced a statistically significant rescue, with p.(Arg51Leu) showing the highest degree of functional deficiency. Dominant variants in a close homolog of MAB21L1, MAB21L2, have been associated with microphthalmia and/or coloboma and repeatedly involved the same Arg51 residue, further supporting its pathogenicity. The possible role of p.(Arg62Cys) and p.(Gly220Arg) in microphthalmia is similarly supported by the observed functional defects, with or without an additional impact from noncoding MAB21L1 variants identified in each patient. This study suggests a broader spectrum of MAB21L1-associated disease.
Collapse
Affiliation(s)
- Sarah E. Seese
- Department of Pediatrics and Children's Research Institute, Medical College of WisconsinChildren's of WisconsinMilwaukeeWIUSA
- Department of Cell Biology, Neurobiology, and AnatomyThe Medical College of WisconsinMilwaukeeWisconsinUSA
| | - Linda M. Reis
- Department of Pediatrics and Children's Research Institute, Medical College of WisconsinChildren's of WisconsinMilwaukeeWIUSA
| | - Brett Deml
- Department of Pediatrics and Children's Research Institute, Medical College of WisconsinChildren's of WisconsinMilwaukeeWIUSA
- Present address:
PreventionGeneticsMarshfieldWisconsinUSA
| | | | | | - Robyn V. Jamieson
- Eye Genetics Research Unit, Sydney Children's Hospitals Network and Children's Medical Research InstituteUniversity of SydneySydneyNew South WalesAustralia
| | - Elena V. Semina
- Department of Pediatrics and Children's Research Institute, Medical College of WisconsinChildren's of WisconsinMilwaukeeWIUSA
- Department of Cell Biology, Neurobiology, and AnatomyThe Medical College of WisconsinMilwaukeeWisconsinUSA
- Department of Ophthalmology and Visual SciencesMedical College of WisconsinMilwaukeeWisconsinUSA
| |
Collapse
|
5
|
Sutter PA, Karki S, Crawley I, Singh V, Bernt KM, Rowe DW, Crocker SJ, Bayarsaihan D, Guzzo RM. Mesenchyme-specific loss of Dot1L histone methyltransferase leads to skeletal dysplasia phenotype in mice. Bone 2021; 142:115677. [PMID: 33022452 PMCID: PMC7744341 DOI: 10.1016/j.bone.2020.115677] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/20/2020] [Accepted: 10/01/2020] [Indexed: 12/17/2022]
Abstract
Chromatin modifying enzymes play essential roles in skeletal development and bone maintenance, and deregulation of epigenetic mechanisms can lead to skeletal growth and malformation disorders. Here, we report a novel skeletal dysplasia phenotype in mice with conditional loss of Disruptor of telomeric silencing 1-like (Dot1L) histone methyltransferase in limb mesenchymal progenitors and downstream descendants. Phenotypic characterizations of mice with Dot1L inactivation by Prrx1-Cre (Dot1L-cKOPrrx1) revealed limb shortening, abnormal bone morphologies, and forelimb dislocations. Our in vivo and in vitro data support a crucial role for Dot1L in regulating growth plate chondrocyte proliferation and differentiation, extracellular matrix production, and secondary ossification center formation. Micro-computed tomography analysis of femurs revealed that partial loss of Dot1L expression is sufficient to impair trabecular bone formation and microarchitecture in young mice. Moreover, RNAseq analysis of Dot1L deficient chondrocytes implicated Dot1L in the regulation of key genes and pathways necessary to promote cell cycle regulation and skeletal growth. Collectively, our data show that early expression of Dot1L in limb mesenchyme provides essential regulatory control of endochondral bone morphology, growth, and stability.
Collapse
Affiliation(s)
- Pearl A Sutter
- Department of Neuroscience, School of Medicine, University of Connecticut Health, Farmington, CT, United States of America
| | - Sangita Karki
- Department of Neuroscience, School of Medicine, University of Connecticut Health, Farmington, CT, United States of America
| | - Ilan Crawley
- Department of Neuroscience, School of Medicine, University of Connecticut Health, Farmington, CT, United States of America
| | - Vijender Singh
- Bioinformatics, University of Connecticut, Storrs, CT, United States of America
| | - Kathrin M Bernt
- Division of Pediatric Oncology, Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania and Abramson Cancer Center, Philadelphia, PA, United States of America
| | - David W Rowe
- Department of Reconstructive Sciences, School of Dental Medicine, University of Connecticut Health, Farmington, CT, United States of America; Center for Regenerative Medicine and Skeletal Development, Farmington, CT, United States of America
| | - Stephen J Crocker
- Department of Neuroscience, School of Medicine, University of Connecticut Health, Farmington, CT, United States of America
| | - Dashzeveg Bayarsaihan
- Department of Reconstructive Sciences, School of Dental Medicine, University of Connecticut Health, Farmington, CT, United States of America; Center for Regenerative Medicine and Skeletal Development, Farmington, CT, United States of America
| | - Rosa M Guzzo
- Department of Neuroscience, School of Medicine, University of Connecticut Health, Farmington, CT, United States of America.
| |
Collapse
|
6
|
Morphometric analysis of the lens in human aniridia and mouse Small eye. Exp Eye Res 2020; 203:108371. [PMID: 33248069 DOI: 10.1016/j.exer.2020.108371] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/17/2020] [Accepted: 11/22/2020] [Indexed: 12/16/2022]
Abstract
Congenital aniridia is caused by heterozygous mutations in the PAX6 gene. In this disease, congenital iris and foveal hypoplasia is associated with juvenile onset cataract, glaucoma, and corneal keratopathy. In rodents, Pax6 mutations result in a congenital reduction in ocular size that is not typically described in human aniridia. Here, the ocular morphometry of aniridia patients is compared with the lens phenotype of Pax6+/tm1/Pgr mice to reveal whether there are species differences in Pax6 regulation of lens development and homeostasis. Ultrasound biometry (UBM) revealed that eleven percent of aniridia patients exhibited mild microphthalmia while the anterior chamber depth of aniridic eyes was significantly reduced from 6 months of age onward. Although aniridic lens thickness was normal from birth, it was significantly decreased in aniridic lenses older than 30. Notably, 86% of aniridic lenses exhibited cataractous changes in this cohort. In addition, a significant proportion of aniridia patients develop lens subluxation as they age associated with reduced lens diameter as measured by anterior segment optical coherence tomography (AS-OCT). Analysis of young adult Pax6+/tm1/Pgr mouse lenses by micro-computed tomography (microCT), bright field and dark field imaging revealed that they are reduced in size but did not exhibit overt cataracts at this age. Overall, this study reveals that congenital microphthalmia as assessed by axial length, or microphakia, as assessed by lens thickness, are not typical in human aniridia, although these are primary manifestations of Pax6 mutations in mice, suggesting that PAX6 regulates some aspects of lens development differently between these species.
Collapse
|
7
|
Abstract
The ability to edit DNA at the nucleotide level using clustered regularly interspaced short palindromic repeats (CRISPR) systems is a relatively new investigative tool that is revolutionizing the analysis of many aspects of human health and disease, including orthopaedic disease. CRISPR, adapted for mammalian cell genome editing from a bacterial defence system, has been shown to be a flexible, programmable, scalable, and easy-to-use gene editing tool. Recent improvements increase the functionality of CRISPR through the engineering of specific elements of CRISPR systems, the discovery of new, naturally occurring CRISPR molecules, and modifications that take CRISPR beyond gene editing to the regulation of gene transcription and the manipulation of RNA. Here, the basics of CRISPR genome editing will be reviewed, including a description of how it has transformed some aspects of molecular musculoskeletal research, and will conclude by speculating what the future holds for the use of CRISPR-related treatments and therapies in clinical orthopaedic practice. Cite this article: Bone Joint Res 2020;9(7):351–359.
Collapse
Affiliation(s)
- Jamie Fitzgerald
- Bone and Joint Center, Henry Ford Hospital, Integrative Biosciences Center, Detroit, Michigan, USA
| |
Collapse
|