ABSTRACT
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.
Subject(s)
Galactose/therapeutic use , Glycogen Storage Disease/drug therapy , Administration, Oral , Adolescent , Blood Coagulation , Blood Glucose/metabolism , Child , Child, Preschool , Creatine Kinase/blood , Dose-Response Relationship, Drug , Female , Galactose/administration & dosage , Galactose/adverse effects , Glycoproteins/metabolism , Humans , Infant , Male , Phosphoglucomutase/metabolism , Pilot Projects , Prospective Studies , Skin/cytology , Skin/metabolism , Transferrin/metabolism , Young AdultABSTRACT
OBJECTIVE: To define phenotypic groups and identify predictors of disease severity in patients with phosphoglucomutase-1 deficiency (PGM1-CDG). STUDY DESIGN: We evaluated 27 patients with PGM1-CDG who were divided into 3 phenotypic groups, and group assignment was validated by a scoring system, the Tulane PGM1-CDG Rating Scale (TPCRS). This scale evaluates measurable clinical features of PGM1-CDG. We examined the relationship between genotype, enzyme activity, and TPCRS score by using regression analysis. Associations between the most common clinical features and disease severity were evaluated by principal component analysis. RESULTS: We found a statistically significant stratification of the TPCRS scores among the phenotypic groups (P < .001). Regression analysis showed that there is no significant correlation between genotype, enzyme activity, and TPCRS score. Principal component analysis identified 5 variables that contributed to 54% variance in the cohort and are predictive of disease severity: congenital malformation, cardiac involvement, endocrine deficiency, myopathy, and growth. CONCLUSIONS: We established a scoring algorithm to reliably evaluate disease severity in patients with PGM1-CDG on the basis of their clinical history and presentation. We also identified 5 clinical features that are predictors of disease severity; 2 of these features can be evaluated by physical examination, without the need for specific diagnostic testing and thus allow for rapid assessment and initiation of therapy.
Subject(s)
Glycogen Storage Disease/diagnosis , Phenotype , Severity of Illness Index , Adolescent , Adult , Algorithms , Child , Child, Preschool , Female , Genetic Markers , Genotype , Glycogen Storage Disease/enzymology , Glycogen Storage Disease/genetics , Humans , Male , Mutation , Phosphoglucomutase/deficiency , Phosphoglucomutase/genetics , Physical Examination , Principal Component Analysis , Regression Analysis , Young AdultABSTRACT
AIM: To describe patients diagnosed with limb girdle muscular dystrophy 2I (LGMD2I) in our paediatric departments between 2004 and 2012. METHODS: The hospital charts of 17 patients presenting for evaluation at a mean age of 7.8 years (range 1-13 years) were retrospectively reviewed. RESULTS: With one exception, all patients were homozygous for the common mutation c.826C>A in the FKRP gene. Three patients experienced transient pronounced weakness as toddlers. Fatigue and muscle pain were most prominent, weakness less so, in children presenting at an older age. The degree of severity varied substantially. In certain cases, increased creatine kinase was an incidental finding. All walked independently by 18 months. When last evaluated at a mean age of 14.3 years (range 3.5-18 years), five patients were part-time wheelchair users. One patient was then treated for a cardiomyopathy. Creatine kinase was consistently increased, except presymptomatic in one patient. Muscle biopsies showed focal acute and chronic myopathic changes and pathological expression of α-dystroglycan. No consistent relationship between clinical function and the degree of morphological pathology was found. CONCLUSION: LGMD2I is a relevant differential diagnosis when creatine kinase is increased in children presenting with fatigue, muscle pain and sometimes weakness.
