1
|
Guo Q, Zhang P, Ying W, Wang Y, Zhu J, Li G, Wang H, Wang X, Lei C, Zhou W, Sun J, Wu B. Intron retention by a novel intronic mutation in DKC1 gene caused recurrent still birth and early death in a Chinese family. Mol Genet Genomic Med 2022; 10:e1934. [PMID: 35384376 PMCID: PMC9184655 DOI: 10.1002/mgg3.1934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 02/09/2022] [Accepted: 03/14/2022] [Indexed: 11/06/2022] Open
Abstract
Background DKC1, the dyskerin encoding gene, functions in telomerase activity and telomere maintenance. DKC1 mutations cause a multisystem disease, dyskeratosis congenita (DC), which is associated with immunodeficiency and bone marrow failure. Methods In this research, we reported a novel intronic mutation of DKC1 causing dyskerin functional loss in a Chinese family. Whole exome sequence (WES) of the proband and validation by sanger sequencing help us identify a pathogenic DKC1 mutation. Minigene splicing assays were performed to evaluate functional change of DKC1. Results A pathogenic DKC1 intronic mutation(c.84 + 7A > G) was identified in the proband, which was inherited from heterozygous mother and not reported before. We detected the novel transcript with a 7 bp intron retention through minigene splicing assay. The newly spliced transcript is so short that would be degraded by nonsense‐mediated mRNA decay in vitro and we infer that the novel DKC1 mutation would influences normal physiological function of dyskerin. Conclusions Our study identified a novel intronic mutation, which expands the spectrum of pathogenic DKC1 gene mutations and can be used in molecular diagnosis. The mutant allele was transmitted to the next generation with high frequency in the family and causes still birth or early death.
Collapse
Affiliation(s)
- Qiufang Guo
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China.,Berry Genomics Co., Beijing, China
| | - Ping Zhang
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Wenjing Ying
- Department of Allergy and Clinical Immunology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Yaqiong Wang
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Jitao Zhu
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Gang Li
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Huijun Wang
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Xiaochuan Wang
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Caixia Lei
- Prenatal Diagnosis Center, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China
| | - Wenhao Zhou
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Jinqiao Sun
- Department of Allergy and Clinical Immunology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Bingbing Wu
- Center of Molecular Medicine, Pediatrics Research Institute, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| |
Collapse
|
2
|
Lansdorp PM. Sex differences in telomere length, lifespan, and embryonic dyskerin levels. Aging Cell 2022; 21:e13614. [PMID: 35441417 PMCID: PMC9124296 DOI: 10.1111/acel.13614] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 03/20/2022] [Accepted: 04/03/2022] [Indexed: 01/22/2023] Open
Abstract
Telomerase levels in most human cells are insufficient to prevent loss of telomeric DNA with each replication cycle. The resulting “Hayflick” limit may have allowed lifespan to increase by suppressing the development of tumors early in life be it at the expense of compromised cellular responses late in life. At any given age, the average telomere length in leukocytes shows considerably variation between individuals with females having, on average, longer telomeres than males. Sex differences in average telomere length are already present at birth and correspond to reported differences in the average life expectancy between the sexes. Levels of telomerase RNA and dyskerin, encoded by DKC1, are known to limit telomerase activity in embryonic stem cells. X‐linked DKC1 is expressed from both alleles in female embryo cells and higher levels of dyskerin and telomerase could elongate telomeres prior to embryo implantation. The hypothesis that embryonic telomerase levels set the stage for the sex differences in telomere length and lifespan deserves further study.
Collapse
Affiliation(s)
- Peter M. Lansdorp
- Terry Fox Laboratory BC Cancer Agency Vancouver BC Canada
- Department of Medical Genetics University of British Columbia Vancouver BC Canada
| |
Collapse
|
3
|
Zeng T, Lv G, Chen X, Yang L, Zhou L, Dou Y, Tang X, Yang J, An Y, Zhao X. CD8 + T-cell senescence and skewed lymphocyte subsets in young Dyskeratosis Congenita patients with PARN and DKC1 mutations. J Clin Lab Anal 2020; 34:e23375. [PMID: 32452087 PMCID: PMC7521304 DOI: 10.1002/jcla.23375] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/16/2020] [Accepted: 05/01/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Dyskeratosis congenita (DC) is a syndrome resulting from defective telomere maintenance. Immunodeficiency associated with DC can cause significant morbidity and lead to premature mortality, but the immunological characteristics and molecular hallmark of DC patients, especially young patients, have not been described in detail. METHODS We summarize the clinical data of two juvenile patients with DC. Gene mutations were identified by whole-exome and direct sequencing. Swiss-PdbViewer was used to predict the pathogenicity of identified mutations. The relative telomere length was determined by QPCR, and a comprehensive analysis of lymphocyte subsets and CD57 expression was performed by flow cytometry. RESULTS Both patients showed typical features of DC without severe infection. In addition, patient 1 (P1) was diagnosed with Hoyeraal-Hreidarsson syndrome due to cerebellar hypoplasia. Gene sequencing showed P1 had a compound heterozygous mutation (c.204G > T and c.178-245del) in PARN and P2 had a novel hemizygous mutation in DKC1 (c.1051A > G). Lymphocyte subset analysis showed B and NK cytopenia, an inverted CD4:CD8 ratio, and decreased naïve CD4 and CD8 cells. A significant increase in CD21low B cells and skewed numbers of helper T cells (Th), regulatory T cells (Treg), follicular regulatory T cells (Tfr), and follicular helper T cells (Tfh) were also detected. Short telomere lengths, increased CD57 expression, and an expansion of CD8 effector memory T cells re-expressing CD45RA (TEMRA) were also found in both patients. CONCLUSION Unique immunologic abnormalities, CD8 T-cell senescence, and shortened telomere together as a hallmark occur in young DC patients before progression to severe disease.
Collapse
Affiliation(s)
- Ting Zeng
- Pediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and Disorders (Chongqing)China International Science and Technology Cooperation base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Chongqing Key Laboratory of Child Infection and ImmunityChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Ge Lv
- Pediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and Disorders (Chongqing)China International Science and Technology Cooperation base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Chongqing Key Laboratory of Child Infection and ImmunityChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Xuemei Chen
- Pediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and Disorders (Chongqing)China International Science and Technology Cooperation base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Chongqing Key Laboratory of Child Infection and ImmunityChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Lu Yang
- Pediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and Disorders (Chongqing)China International Science and Technology Cooperation base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Chongqing Key Laboratory of Child Infection and ImmunityChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Lina Zhou
- Pediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and Disorders (Chongqing)China International Science and Technology Cooperation base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Chongqing Key Laboratory of Child Infection and ImmunityChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Ying Dou
- Pediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and Disorders (Chongqing)China International Science and Technology Cooperation base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Chongqing Key Laboratory of Child Infection and ImmunityChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Department of Hematology and OncologyChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Xuemei Tang
- Pediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and Disorders (Chongqing)China International Science and Technology Cooperation base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Chongqing Key Laboratory of Child Infection and ImmunityChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Department of Rheumatology and ImmunologyChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Jun Yang
- Pediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and Disorders (Chongqing)China International Science and Technology Cooperation base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Chongqing Key Laboratory of Child Infection and ImmunityChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Department of Rheumatology and ImmunologyShenzhen Children's HospitalShenzhenChina
| | - Yunfei An
- Pediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and Disorders (Chongqing)China International Science and Technology Cooperation base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Chongqing Key Laboratory of Child Infection and ImmunityChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Department of Rheumatology and ImmunologyChildren's Hospital of Chongqing Medical UniversityChongqingChina
| | - Xiaodong Zhao
- Pediatric Research InstituteMinistry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and Disorders (Chongqing)China International Science and Technology Cooperation base of Child Development and Critical DisordersChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Chongqing Key Laboratory of Child Infection and ImmunityChildren's Hospital of Chongqing Medical UniversityChongqingChina
- Department of Rheumatology and ImmunologyChildren's Hospital of Chongqing Medical UniversityChongqingChina
| |
Collapse
|