Hypomorphic homozygous mutations in phosphoglucomutase 3 (PGM3) impair immunity and increase serum IgE levels
- J Allergy Clin Immunol. 2014 May;133(5):1410-9, 1419.e1-13. doi: 10.1016/j.jaci.2014.02.025.
- 1. Laboratory of Immunopathology, Vaccinology and Molecular Genetics, Pasteur Institute of Tunis and University Tunis El Manar, Tunis, Tunisia.
- 2. Center for Chronic Immunodeficiency (CCI), University Medical Center Freiburg, Freiburg, Germany.
- 3. Department of Life Sciences, Imperial College London, London, United Kingdom.
- 4. Pediatrics Department, Bone Marrow Transplantation Center, Tunis, Tunisia.
- 5. Department of Pediatrics, Division of Pediatric Hematology and Oncology, Faculty of Medicine, Erciyes University, Kayseri, Turkey; Department of Pediatrics, Division of Pediatric Immunology, Faculty of Medicine, Erciyes University, Kayseri, Turkey.
- 6. Department of Pediatrics, Division of Pediatric Hematology and Oncology, Faculty of Medicine, Erciyes University, Kayseri, Turkey.
- 7. Department of Pediatric Infectious Diseases, CHU IBN ROCHD, Hassan II University, Casablanca, Morocco.
- 8. Laboratory of Venoms and Therapeutic Molecules, Institut Pasteur de Tunis, Tunis, Tunisia.
- 9. Department of Medicine I, Specialties: Hematology, Oncology, and Stem-Cell Transplantation, University Medical Center Freiburg, Freiburg, Germany.
- 10. Allergy Research Group, Department of Dermatology, University Medical Center Freiburg, Freiburg, Germany.
- 11. Pediatrics Department A, Children's Hospital of Tunis, Tunis, Tunisia.
- 12. Clinical Research Center, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Huddinge, Sweden.
- 13. Department of Immunology, Genetics and Pathology, Uppsala University, Rudbeck Laboratory, Uppsala, Sweden.
- 14. Department of Pediatrics, Division of Pediatric Immunology, Faculty of Medicine, Erciyes University, Kayseri, Turkey.
- 15. Royal Free Hospital, Institute of Immunity & Transplantation, University College London, London, United Kingdom.
- 16. Institute of Virology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
- 17. Division of Immunology, Labor Berlin and Institute of Medical Immunology, Charité, Campus Virchow Klinikum, Berlin, Germany.
- 18. Department of Genetics, Hassan II University, Casablanca, Morocco.
- 19. National Center for Biotechnology Information, National Institutes of Health, Department of Health and Human Services, Bethesda, Md.
- 20. Center for Chronic Immunodeficiency (CCI), University Medical Center Freiburg, Freiburg, Germany; Royal Free Hospital, Institute of Immunity & Transplantation, University College London, London, United Kingdom. Electronic address: [email protected].
Background: Recurrent Bacterial and Fungal infections, eczema, and increased serum IgE levels characterize patients with the hyper-IgE syndrome (HIES). Known genetic causes for HIES are mutations in signal transducer and activator of transcription 3 (STAT3) and dedicator of cytokinesis 8 (DOCK8), which are involved in signal transduction pathways. However, glycosylation defects have not been described in patients with HIES. One crucial enzyme in the glycosylation pathway is phosphoglucomutase 3 (PGM3), which catalyzes a key step in the synthesis of uridine diphosphate N-acetylglucosamine, which is required for the biosynthesis of N-glycans.
Objective: We sought to elucidate the genetic cause in patients with HIES who do not carry mutations in STAT3 or DOCK8.
Methods: After establishing a linkage interval by means of SNPchip genotyping and homozygosity mapping in 2 families with HIES from Tunisia, mutational analysis was performed with selector-based, high-throughput Sequencing. Protein expression was analyzed by means of Western blotting, and glycosylation was profiled by using mass spectrometry.
Results: Mutational analysis of candidate genes in an 11.9-Mb linkage region on chromosome 6 shared by 2 multiplex families identified 2 homozygous mutations in PGM3 that segregated with disease status and followed recessive inheritance. The mutations predict amino acid changes in PGM3 (p.Glu340del and p.Leu83Ser). A third homozygous mutation (p.Asp502Tyr) and the p.Leu83Ser variant were identified in 2 Other affected families, respectively. These hypomorphic mutations have an effect on the biosynthetic reactions involving uridine diphosphate N-acetylglucosamine. Glycomic analysis revealed an aberrant glycosylation pattern in leukocytes demonstrated by a reduced level of tri-antennary and tetra-antennary N-glycans. T-cell proliferation and differentiation were impaired in patients. Most patients had developmental delay, and many had psychomotor retardation.
Conclusion: Impairment of PGM3 function leads to a novel primary (inborn) error of development and immunity because biallelic hypomorphic mutations are associated with impaired glycosylation and a hyper-IgE-like phenotype.