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Pajusalu S, Vals MA, Mihkla L, Šamarina U, Kahre T, Õunap K. The Estimated Prevalence of N-Linked Congenital Disorders of Glycosylation Across Various Populations Based on Allele Frequencies in General Population Databases. Front Genet 2021; 12:719437. [PMID: 34447415 PMCID: PMC8383291 DOI: 10.3389/fgene.2021.719437] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 07/21/2021] [Indexed: 01/16/2023] Open
Abstract
Congenital disorders of glycosylation (CDG) are a widely acknowledged group of metabolic diseases. PMM2-CDG is the most frequently diagnosed CDG with a prevalence as high as one in 20,000. In contrast, the prevalence of other CDG types remains unknown. This study aimed to analyze the estimated prevalence of different N-linked protein glycosylation disorders. We extracted allele frequencies for diverse populations from The Genome Aggregation Database (gnomAD), encompassing variant frequency information from 141,456 individuals. To identify pathogenic variants, we used the ClinVar database as a primary source. High confidence loss-of-function variants as defined by the LOFTEE algorithm were also classified as pathogenic. After summing up population frequencies for pathogenic alleles, estimated disease birth prevalence values with confidence intervals were calculated using the Bayesian method. We first validated our approach using two more common recessive disorders (cystic fibrosis and phenylketonuria) by showing that the estimated prevalences calculated from population allele frequencies were in accordance with previously published epidemiological studies. Among assessed 27 autosomal recessive N-glycosylation disorders, the only disease with estimated birth prevalence higher than one in 100,000 was PMM2-CDG (in both, all gnomAD individuals and those with European ancestry). The combined prevalence of 27 different N-glycosylation disorders was around one in 22,000 Europeans but varied considerably across populations. We will show estimated prevalence data from diverse populations and explain the possible pitfalls of this analysis. Still, we are confident that these data will guide CDG research and clinical care to identify CDG across populations.
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Affiliation(s)
- Sander Pajusalu
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia.,Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
| | - Mari-Anne Vals
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia.,Children's Clinic, Tartu University Hospital, Tartu, Estonia
| | - Laura Mihkla
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia.,Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
| | - Ustina Šamarina
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
| | - Tiina Kahre
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia.,Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
| | - Katrin Õunap
- Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia.,Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
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Mandel H, Cohen Kfir N, Fedida A, Shuster Biton E, Odeh M, Kalfon L, Ben-Harouch S, Fleischer Sheffer V, Hoffman Y, Goldberg Y, Dinwiddie A, Dumin E, Eran A, Apel-Sarid L, Tiosano D, Falik-Zaccai TC. COG6-CDG: Expanding the phenotype with emphasis on glycosylation defects involved in the causation of male disorders of sex development. Clin Genet 2020; 98:402-407. [PMID: 32683677 DOI: 10.1111/cge.13816] [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: 06/16/2020] [Revised: 07/12/2020] [Accepted: 07/13/2020] [Indexed: 12/11/2022]
Abstract
COG6-congenital disorder of glycosylation (COG6-CDG) is caused by biallelic mutations in COG6. To-date, 12 variants causing COG6-CDG in less than 20 patients have been reported. Using whole exome sequencing we identified two siblings with a novel homozygous deletion of 26 bp in COG6, creating a splicing variant (c.518_540 + 3del) and a shift in the reading frame. The phenotype of COG6-CDG includes growth and developmental retardation, microcephaly, liver and gastrointestinal disease, hypohydrosis and recurrent infections. We report two patients with novel phenotypic features including bowel malrotation and ambiguous genitalia, directing attention to the role of glycoprotein metabolism in the causation of disorders of sex development (DSD). Searching the glycomic literature, we identified 14 CDGs including males with DSD, a feature not previously accentuated. This study broadens the genetic and phenotypic spectrum of COG6-CDG and calls for increasing awareness to the central role of glycosylation processes in development of human sex and genitalia.
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Affiliation(s)
- Hanna Mandel
- Institute of Human Genetics, Galilee Medical Center, Nahariya, Israel
| | - Nehama Cohen Kfir
- Institute of Human Genetics, Galilee Medical Center, Nahariya, Israel.,Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Ayalla Fedida
- Institute of Human Genetics, Galilee Medical Center, Nahariya, Israel.,Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | | | - Marwan Odeh
- Ultra-Sound Unit, Galilee Medical Center, Nahariya, Israel
| | - Limor Kalfon
- Institute of Human Genetics, Galilee Medical Center, Nahariya, Israel
| | - Shani Ben-Harouch
- Institute of Human Genetics, Galilee Medical Center, Nahariya, Israel
| | | | | | - Yael Goldberg
- Ultrasound Unit, Carmel Medical Center, Haifa, Israel
| | - April Dinwiddie
- Diagnostics Department, Center for Genomics and Transcriptomics (CeGaT) GmbH and Practice for Human Genetics, Tübingen, Germany
| | - Elena Dumin
- Clinical Biochemistry Laboratory, Rambam Health Care Campus, Haifa, Israel
| | - Ayelet Eran
- Neuroradiology Unit, Radiology Department, Rambam Health Care Campus, Haifa, Israel
| | - Liat Apel-Sarid
- Department of Pathology, Galilee Medical Center, Nahariya, Israel
| | - Dov Tiosano
- Pediatric Endocrinology Department, Rambam Health Care Campus, Haifa, Israel
| | - Tzipora C Falik-Zaccai
- Institute of Human Genetics, Galilee Medical Center, Nahariya, Israel.,Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
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