Phosphoglucomutase 1 (PGM1) deficiency is a rare genetic disorder that affects glycogen metabolism, glycolysis, and protein glycosylation. Previously known as GSD XIV, it was recently reclassified as a congenital disorder of glycosylation, PGM1-CDG. PGM1-CDG usually manifests as a multisystem disease. Most patients present as infants with cleft palate, liver function abnormalities and hypoglycemia, but some patients present in adulthood with isolated muscle involvement. Some patients develop life-threatening cardiomyopathy. Unlike most other CDG, PGM1-CDG has an effective treatment option, d-galactose, which has been shown to improve many of the patients' symptoms. Therefore, early diagnosis and initiation of treatment for PGM1-CDG patients are crucial decisions. In this article, our group of international experts suggests diagnostic, follow-up, and management guidelines for PGM1-CDG. These guidelines are based on the best available evidence-based data and experts' opinions aiming to provide a practical resource for health care providers to facilitate successful diagnosis and optimal management of PGM1-CDG patients.

• Klíčová slova
• d-galactose, PGM1-CDG, congenital disorder of glycosylation, management guidelines, phosphoglucomutase 1 deficiency,
• MeSH
• dospělí MeSH
• galaktosa terapeutické užití   MeSH
• glykogenóza komplikace   diagnóza   farmakoterapie   enzymologie   MeSH
• hypoglykemie komplikace   MeSH
• kardiomyopatie komplikace   patologie   MeSH
• kojenec MeSH
• konsensus MeSH
• lidé MeSH
• management nemoci * MeSH
• mezinárodní spolupráce MeSH
• nemoci svalů komplikace   patologie   MeSH
• rozštěp patra komplikace   patologie   MeSH
• Check Tag
• dospělí MeSH
• kojenec MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH
• směrnice pro lékařskou praxi MeSH
• Názvy látek
• galaktosa MeSH

Mannose phosphate isomerase-congenital disorder of glycosylation (MPI-CDG) deficiency is a rare subtype of congenital disorders of protein N-glycosylation. It is characterised by deficiency of MPI caused by pathogenic variants in MPI gene. The manifestation of MPI-CDG is different from other CDGs as the patients suffer dominantly from gastrointestinal and hepatic involvement whereas they usually do not present intellectual disability or neurological impairment. It is also one of the few treatable subtypes of CDGs with proven effect of oral mannose. This article covers a complex review of the literature and recommendations for the management of MPI-CDG with an emphasis on the clinical aspect of the disease. A team of international experts elaborated summaries and recommendations for diagnostics, differential diagnosis, management, and treatment of each system/organ involvement based on evidence-based data and experts' opinions. Those guidelines also reveal more questions about MPI-CDG which need to be further studied.

• Klíčová slova
• AT deficiency, MPI-CDG, guidelines, hepatic fibrosis, hyperinsulinaemic hypoglycaemia, mannose phosphate isomerase, protein-losing enteropathy,
• MeSH
• konsensus MeSH
• lidé MeSH
• management nemoci MeSH
• mannosa-6-fosfátisomerasa nedostatek   genetika   MeSH
• směrnice pro lékařskou praxi jako téma MeSH
• vrozené poruchy glykosylace diagnóza   enzymologie   terapie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• mannosa-6-fosfátisomerasa MeSH

Phosphoglucomutase 1 (PGM1) encodes the metabolic enzyme that interconverts glucose-6-P and glucose-1-P. Mutations in PGM1 cause impairment in glycogen metabolism and glycosylation, the latter manifesting as a congenital disorder of glycosylation (CDG). This unique metabolic defect leads to abnormal N-glycan synthesis in the endoplasmic reticulum (ER) and the Golgi apparatus (GA). On the basis of the decreased galactosylation in glycan chains, galactose was administered to individuals with PGM1-CDG and was shown to markedly reverse most disease-related laboratory abnormalities. The disease and treatment mechanisms, however, have remained largely elusive. Here, we confirm the clinical benefit of galactose supplementation in PGM1-CDG-affected individuals and obtain significant insights into the functional and biochemical regulation of glycosylation. We report here that, by using tracer-based metabolomics, we found that galactose treatment of PGM1-CDG fibroblasts metabolically re-wires their sugar metabolism, and as such replenishes the depleted levels of galactose-1-P, as well as the levels of UDP-glucose and UDP-galactose, the nucleotide sugars that are required for ER- and GA-linked glycosylation, respectively. To this end, we further show that the galactose in UDP-galactose is incorporated into mature, de novo glycans. Our results also allude to the potential of monosaccharide therapy for several other CDG.

• Klíčová slova
• CDG, PGM1-CDG, central carbon metabolism, galactose, glycosylation, mitochondria, nucleotide sugars, tracer metabolomics,
• MeSH
• fibroblasty účinky léků   metabolismus   patologie   MeSH
• fosfoglukomutasa nedostatek   MeSH
• galaktosa aplikace a dávkování   MeSH
• glykosylace MeSH
• kohortové studie MeSH
• kultivované buňky MeSH
• lidé MeSH
• uridindifosfátgalaktosa metabolismus   MeSH
• uridindifosfátglukosa metabolismus   MeSH
• vrozené poruchy glykosylace farmakoterapie   metabolismus   patologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfoglukomutasa MeSH
• galaktosa MeSH
• uridindifosfátgalaktosa MeSH
• uridindifosfátglukosa MeSH

PurposePhosphoglucomutase-1 deficiency is a subtype of congenital disorders of glycosylation (PGM1-CDG). Previous casereports in PGM1-CDG patients receiving oral D-galactose (D-gal) showed clinical improvement. So far no systematic in vitro and clinical studies have assessed safety and benefits of D-gal supplementation. In a prospective pilot study, we evaluated the effects of oral D-gal in nine patients.MethodsD-gal supplementation was increased to 1.5 g/kg/day (maximum 50 g/day) in three increments over 18 weeks. Laboratory studies were performed before and during treatment to monitor safety and effect on serum transferrin-glycosylation, coagulation, and liver and endocrine function. Additionally, the effect of D-gal on cellular glycosylation was characterized in vitro.ResultsEight patients were compliant with D-gal supplementation. No adverse effects were reported. Abnormal baseline results (alanine transaminase, aspartate transaminase, activated partial thromboplastin time) improved or normalized already using 1 g/kg/day D-gal. Antithrombin-III levels and transferrin-glycosylation showed significant improvement, and increase in galactosylation and whole glycan content. In vitro studies before treatment showed N-glycan hyposialylation, altered O-linked glycans, abnormal lipid-linked oligosaccharide profile, and abnormal nucleotide sugars in patient fibroblasts. Most cellular abnormalities improved or normalized following D-gal treatment. D-gal increased both UDP-Glc and UDP-Gal levels and improved lipid-linked oligosaccharide fractions in concert with improved glycosylation in PGM1-CDG.ConclusionOral D-gal supplementation is a safe and effective treatment for PGM1-CDG in this pilot study. Transferrin glycosylation and ATIII levels were useful trial end points. Larger, longer-duration trials are ongoing.

• MeSH
• aplikace orální MeSH
• dítě MeSH
• fosfoglukomutasa metabolismus   MeSH
• galaktosa aplikace a dávkování   škodlivé účinky   terapeutické užití   MeSH
• glykogenóza farmakoterapie   MeSH
• glykoproteiny metabolismus   MeSH
• hemokoagulace MeSH
• kojenec MeSH
• kreatinkinasa krev   MeSH
• krevní glukóza metabolismus   MeSH
• kůže cytologie   metabolismus   MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• pilotní projekty MeSH
• předškolní dítě MeSH
• prospektivní studie MeSH
• transferin metabolismus   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• fosfoglukomutasa MeSH
• galaktosa MeSH
• glykoproteiny MeSH
• kreatinkinasa MeSH
• krevní glukóza MeSH
• PGM1 protein, human MeSH Prohlížeč
• transferin MeSH