Publications

• PGM3 mutations cause a congenital disorder of glycosylation with severe immunodeficiency and skeletal dysplasia.

  Baylor-Johns Hopkins Center for Mendelian Genomics, Stray-Pedersen A., Backe P.H., Sorte H.S., Moerkrid L., Chokshi N.Y., Erichsen H.C., Gambin T., Elgstoeen K.B., Bjoeraas M., Wlodarski M.W., Krueger M., Jhangiani S.N., Muzny D.M., Patel A., Raymond K.M., Sasa G.S., Krance R.A., Martinez C.A., Abraham S.M., Speckmann C., Ehl S., Hall P., Forbes L.R., Merckoll E., Westvik J., Nishimura G., Rustad C.F., Abrahamsen T.G., Roennestad A., Osnes L.T., Egeland T., Roedningen O.K., Beck C.R., Boerwinkle E.A., Gibbs R.A., Lupski J.R., Orange J.S., Lausch E., Hanson I.C.

  Human phosphoglucomutase 3 (PGM3) catalyzes the conversion of N-acetyl-glucosamine (GlcNAc)-6-phosphate into GlcNAc-1-phosphate during the synthesis of uridine diphosphate (UDP)-GlcNAc, a sugar nucleotide critical to multiple glycosylation pathways. We identified three unrelated children with recu ... >> More

  Human phosphoglucomutase 3 (PGM3) catalyzes the conversion of N-acetyl-glucosamine (GlcNAc)-6-phosphate into GlcNAc-1-phosphate during the synthesis of uridine diphosphate (UDP)-GlcNAc, a sugar nucleotide critical to multiple glycosylation pathways. We identified three unrelated children with recurrent infections, congenital leukopenia including neutropenia, B and T cell lymphopenia, and progression to bone marrow failure. Whole-exome sequencing demonstrated deleterious mutations in PGM3 in all three subjects, delineating their disease to be due to an unsuspected congenital disorder of glycosylation (CDG). Functional studies of the disease-associated PGM3 variants in E. coli cells demonstrated reduced PGM3 activity for all mutants tested. Two of the three children had skeletal anomalies resembling Desbuquois dysplasia: short stature, brachydactyly, dysmorphic facial features, and intellectual disability. However, these additional features were absent in the third child, showing the clinical variability of the disease. Two children received hematopoietic stem cell transplantation of cord blood and bone marrow from matched related donors; both had successful engraftment and correction of neutropenia and lymphopenia. We define PGM3-CDG as a treatable immunodeficiency, document the power of whole-exome sequencing in gene discoveries for rare disorders, and illustrate the utility of genomic analyses in studying combined and variable phenotypes. << Less

  Am. J. Hum. Genet. 95:96-107(2014) [PubMed] [EuropePMC]

• Autosomal recessive phosphoglucomutase 3 (PGM3) mutations link glycosylation defects to atopy, immune deficiency, autoimmunity, and neurocognitive impairment.

  Zhang Y., Yu X., Ichikawa M., Lyons J.J., Datta S., Lamborn I.T., Jing H., Kim E.S., Biancalana M., Wolfe L.A., DiMaggio T., Matthews H.F., Kranick S.M., Stone K.D., Holland S.M., Reich D.S., Hughes J.D., Mehmet H., McElwee J., Freeman A.F., Freeze H.H., Su H.C., Milner J.D.

  <h4>Background</h4>Identifying genetic syndromes that lead to significant atopic disease can open new pathways for investigation and intervention in allergy.<h4>Objective</h4>We sought to define a genetic syndrome of severe atopy, increased serum IgE levels, immune deficiency, autoimmunity, and mo ... >> More

  <h4>Background</h4>Identifying genetic syndromes that lead to significant atopic disease can open new pathways for investigation and intervention in allergy.<h4>Objective</h4>We sought to define a genetic syndrome of severe atopy, increased serum IgE levels, immune deficiency, autoimmunity, and motor and neurocognitive impairment.<h4>Methods</h4>Eight patients from 2 families with similar syndromic features were studied. Thorough clinical evaluations, including brain magnetic resonance imaging and sensory evoked potentials, were performed. Peripheral lymphocyte flow cytometry, antibody responses, and T-cell cytokine production were measured. Whole-exome sequencing was performed to identify disease-causing mutations. Immunoblotting, quantitative RT-PCR, enzymatic assays, nucleotide sugar, and sugar phosphate analyses, along with matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry of glycans, were used to determine the molecular consequences of the mutations.<h4>Results</h4>Marked atopy and autoimmunity were associated with increased T(H)2 and T(H)17 cytokine production by CD4(+) T cells. Bacterial and viral infection susceptibility were noted along with T-cell lymphopenia, particularly of CD8(+) T cells, and reduced memory B-cell numbers. Apparent brain hypomyelination resulted in markedly delayed evoked potentials and likely contributed to neurologic abnormalities. Disease segregated with novel autosomal recessive mutations in a single gene, phosphoglucomutase 3 (PGM3). Although PGM3 protein expression was variably diminished, impaired function was demonstrated by decreased enzyme activity and reduced uridine diphosphate-N-acetyl-D-glucosamine, along with decreased O- and N-linked protein glycosylation in patients' cells. These results define a new congenital disorder of glycosylation.<h4>Conclusions</h4>Autosomal recessive hypomorphic PGM3 mutations underlie a disorder of severe atopy, immune deficiency, autoimmunity, intellectual disability, and hypomyelination. << Less

  J. Allergy Clin. Immunol. 133:1400-1409(2014) [PubMed] [EuropePMC]

• Hypomorphic homozygous mutations in phosphoglucomutase 3 (PGM3) impair immunity and increase serum IgE levels.

  Sassi A., Lazaroski S., Wu G., Haslam S.M., Fliegauf M., Mellouli F., Patiroglu T., Unal E., Ozdemir M.A., Jouhadi Z., Khadir K., Ben-Khemis L., Ben-Ali M., Ben-Mustapha I., Borchani L., Pfeifer D., Jakob T., Khemiri M., Asplund A.C., Gustafsson M.O., Lundin K.E., Falk-Soerqvist E., Moens L.N., Gungor H.E., Engelhardt K.R., Dziadzio M., Stauss H., Fleckenstein B., Meier R., Prayitno K., Maul-Pavicic A., Schaffer S., Rakhmanov M., Henneke P., Kraus H., Eibel H., Koelsch U., Nadifi S., Nilsson M., Bejaoui M., Schaeffer A.A., Smith C.I., Dell A., Barbouche M.R., Grimbacher B.

  <h4>Background</h4>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 (D ... >> More

  <h4>Background</h4>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.<h4>Objective</h4>We sought to elucidate the genetic cause in patients with HIES who do not carry mutations in STAT3 or DOCK8.<h4>Methods</h4>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.<h4>Results</h4>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.<h4>Conclusion</h4>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. << Less

  J. Allergy Clin. Immunol. 133:1410-1419(2014) [PubMed] [EuropePMC]

• Characterization of the essential yeast gene encoding N-acetylglucosamine-phosphate mutase.

  Hofmann M., Boles E., Zimmermann F.K.

  A previously cloned gene of Saccharomyces cerevisiae, which complements the growth defect of a phosphoglucomutase (pgm1 delta/pgm2 delta) double deletion mutant on a pure galactose medium [Boles, E., Liebetrau, W., Hofmann, M. & Zimmermann, F. K. (1994) Eur. J. Biochem. 220, 83-96], was identified ... >> More

  A previously cloned gene of Saccharomyces cerevisiae, which complements the growth defect of a phosphoglucomutase (pgm1 delta/pgm2 delta) double deletion mutant on a pure galactose medium [Boles, E., Liebetrau, W., Hofmann, M. & Zimmermann, F. K. (1994) Eur. J. Biochem. 220, 83-96], was identified as the structural gene encoding N-acetylglucosamine-phosphate mutase. The complete nucleotide sequence of the gene, AGM1, and surrounding regions were determined. AGM1 codes for a predicted 62-kDa protein with 557 amino acids and is located on chromosome V adjacent to the known gene PRB1 encoding protease B. No extended nucleotide or amino acid sequence similarities could be found in the databases, except for a small region of amino acids with high similarity to the active-site consensus sequence of hexosephosphate mutases. Three putative pheromone-responsive elements have been identified in the upstream region of the AGM1 gene. The gene is essential for cell viability. An agm1 deletion mutant progresses through only approximately five cell cycles to form a 'string' of undivided cells with an abnormal cell morphology resembling glucosamine auxotrophic mutants. Expression of the AGM1 gene on a multi-copy plasmid led to a significantly increased N-acetylglucosamine-phosphate mutase activity. Unlike over-expression of the AGM1 gene in a pgm1/pgm2 double deletion mutant which could restore phosphoglucomutase activity, over-expression of the PGM2 gene encoding the major isoenzyme of phosphoglucomutase did not increase N-acetylglucosamine-phosphate-mutase activity and did not restore growth of agm1 deletion mutant cells. Our observations indicate that the different hexosephosphate mutases of S. cerevisiae have partially overlapping substrate specificities but, nevertheless, distinct physiological functions. << Less

  Eur. J. Biochem. 221:741-747(1994) [PubMed] [EuropePMC]

• Mechanism of phosphoacetylglucosamine mutase.

  Cheng P.W., Carlson D.M.

  Kinetic studies of phosphoacetylglucosamine mutase (EC 2.7.5.2) for the following reactions: 1) Glc-1-P in equilibrium Glc-6-P and 2) GlcNAc-1-P in equilibrium GlcNAc-6-P have been conducted in the presence of Glc-1,6-P2 and GlcNAc-1,6-P2, respectively. In the first reaction, the initial velocity ... >> More

  Kinetic studies of phosphoacetylglucosamine mutase (EC 2.7.5.2) for the following reactions: 1) Glc-1-P in equilibrium Glc-6-P and 2) GlcNAc-1-P in equilibrium GlcNAc-6-P have been conducted in the presence of Glc-1,6-P2 and GlcNAc-1,6-P2, respectively. In the first reaction, the initial velocity studies at various concentrations of one substrate showed a series of parallel lines in the Line-weaver-Burk plot when the concentrations of the other substrate were changed at several fixed levels. For both reactions, the initial velocity studies performed at fixed ratios of both substrates showed linear lines in the double reciprocal plot. The competitive substrate inhibition pattern was observed in the second reaction. A ping-pong mechanism is proposed for phosphoacetyl-glucosamine mutase. In addition, phosphoacetylglucosamine mutase can be phosphorylated by the addition of Glc-1-[32P]P probably via the reaction of Glc-1-[32P]P with the phosphoenzyme followed by the release of glucose-monophosphate leaving the 32P with the phosphoenzyme. The linkage between the phosphoryl residue and enzyme is stable in acid, but labile in alkali, suggesting phosphoserine (or phosphothreonine) as the phosphorylated amino acid. Biphasic heat denaturation curves suggest the existence of heat-stable and heat-labile forms of this enzyme. << Less

  J. Biol. Chem. 254:8353-8357(1979) [PubMed] [EuropePMC]

• Functional cloning and mutational analysis of the human cDNA for phosphoacetylglucosamine mutase: identification of the amino acid residues essential for the catalysis.

  Mio T., Yamada-Okabe T., Arisawa M., Yamada-Okabe H.

  In Saccharomyces cerevisiae, phosphoacetylglucosamine mutase is encoded by an essential gene called AGM1. The human AGM1 cDNA (HsAGM1) and the Candida albicans AGM1 gene (CaAGM1) were functionally cloned and characterized by using an S. cerevisiae strain in which the endogenous phosphoacetylglucos ... >> More

  In Saccharomyces cerevisiae, phosphoacetylglucosamine mutase is encoded by an essential gene called AGM1. The human AGM1 cDNA (HsAGM1) and the Candida albicans AGM1 gene (CaAGM1) were functionally cloned and characterized by using an S. cerevisiae strain in which the endogenous phosphoacetylglucosamine mutase was depleted. When expressed in Escherichia coli as fusion proteins with glutathione S-transferase, both HsAgm1 and CaAgm1 proteins displayed phosphoacetylglucosamine mutase activities, demonstrating that they indeed specify phosphoacetylglucosamine mutase. Sequence comparison of HsAgm1p with several hexose-phosphate mutases yielded three domains that are highly conserved among phosphoacetylglucosamine mutases and phosphoglucomutases of divergent organisms. Mutations of the conserved amino acids found in these domains, which were designated region I, II, and III, respectively, demonstrated that alanine substitutions for Ser(64) and His(65) in region I, and for Asp(276), Asp(278), and Arg(281) in region II of HsAgm1p severely diminished the enzyme activity and the ability to rescue the S. cerevisiae agm1Delta null mutant. Conservative mutations of His(65) and Asp(276) restored detectable activities, whereas those of Ser(64), Asp(278), and Arg(281) did not. These results indicate that Ser(64), Asp(278), and Arg(281) of HsAgm1p are residues essential for the catalysis. Because Ser(64) corresponds to the phosphorylating serine in the E. coli phosphoglucosamine mutase, it is likely that the activation of HsAgm1p also requires phosphorylation on Ser(64). Furthermore, alanine substitution for Arg(496) in region III significantly increased the K(m) value for N-acetylglucosamine-6-phosphate, demonstrating that Arg(496) serves as a binding site for N-acetylglucosamine-6-phosphate. << Less

  Biochim. Biophys. Acta 1492:369-376(2000) [PubMed] [EuropePMC]

• Purification and properties of phosphoacetylglucosamine mutase.

  Fernandez-Sorensen A., Carlson D.M.

  J. Biol. Chem. 246:3485-3493(1971) [PubMed] [EuropePMC]