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OBJECTIVE: Epalrestat, an aldose reductase inhibitor increases phosphomannomutase (PMM) enzyme activity in a PMM2-congenital disorders of glycosylation (CDG) worm model. Epalrestat also decreases sorbitol level in diabetic neuropathy. We evaluated the genetic, biochemical, and clinical characteristics, including the Nijmegen Progression CDG Rating Scale (NPCRS), urine polyol levels and fibroblast glycoproteomics in patients with PMM2-CDG. METHODS: We performed PMM enzyme measurements, multiplexed proteomics, and glycoproteomics in PMM2-deficient fibroblasts before and after epalrestat treatment. Safety and efficacy of 0.8 mg/kg/day oral epalrestat were studied in a child with PMM2-CDG for 12 months. RESULTS: PMM enzyme activity increased post-epalrestat treatment. Compared with controls, 24% of glycopeptides had reduced abundance in PMM2-deficient fibroblasts, 46% of which improved upon treatment. Total protein N-glycosylation improved upon epalrestat treatment bringing overall glycosylation toward the control fibroblasts' glycosylation profile. Sorbitol levels were increased in the urine of 74% of patients with PMM2-CDG and correlated with the presence of peripheral neuropathy, and CDG severity rating scale. In the child with PMM2-CDG on epalrestat treatment, ataxia scores improved together with significant growth improvement. Urinary sorbitol levels nearly normalized in 3 months and blood transferrin glycosylation normalized in 6 months. INTERPRETATION: Epalrestat improved PMM enzyme activity, N-glycosylation, and glycosylation biomarkers in vitro. Leveraging cellular glycoproteome assessment, we provided a systems-level view of treatment efficacy and discovered potential novel biosignatures of therapy response. Epalrestat was well-tolerated and led to significant clinical improvements in the first pediatric patient with PMM2-CDG treated with epalrestat. We also propose urinary sorbitol as a novel biomarker for disease severity and treatment response in future clinical trials in PMM2-CDG. ANN NEUROL 20219999:n/a-n/a. ispartof: ANNALS OF NEUROLOGY vol:90 issue:6 pages:887-900 ispartof: location:United States status: published

BACKGROUND & AIMS Although transient elastography (TE) is used to determine liver stiffness as a surrogate to hepatic fibrosis, the normal range in children is not well defined. We performed a systematic review and individual participant data (IPD) meta-analysis to determine the range of liver stiffness in healthy children and evaluate the influence of important biological parameters. METHODS We pooled data from 10 studies that examined healthy children using TE. We divided 1702 children into two groups: ≥3 years (older group) and

BACKGROUND: Phosphomannomutase 2 deficiency (PMM2-CDG) is the most common congenital disorder of glycosylation (CDG). Hypoglycemia has been reported in various CDG including PMM2-CDG. The frequency and etiology of hypoglycemia in PMM2-CDG are not well studied. METHODS: We conducted a systematic review of the literature on genetically and/or biochemically confirmed PMM2-CDG patients who developed hypoglycemia. Prospective follow-up information on the patients who received diazoxide therapy was collected and evaluated. RESULTS: A total of 165 peer-reviewed articles reporting on 933 PMM2-CDG patients were assessed. Hypoglycemia was specifically mentioned only in 23 of these patients (2.5%). Hyperinsulinism was identified in 10 patients (43% of all hypoglycemic patients). Among these 10 patients, seven were successfully treated with diazoxide. However, most patients remained on therapy longer than a year to stay free of hypoglycemia. CONCLUSION: Hypoglycemia is a rarely reported finding in patients with PMM2-CDG. Diazoxide-responsive hyperinsulinism was found to have a good prognosis on medication in our PMM2-CDG patients with hypoglycemia. No genotype-phenotype correlation was observed with respect to hyperinsulinism. A prospective study should be undertaken to explore the hypothesis that hypoglycemia is underdiagnosed in PMM2-CDG and to evaluate whether hyperinsulinism is always associated with hypoglycemia. ispartof: JIMD Rep vol:51 issue:1 pages:76-81 ispartof: location:United States status: Published online

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. ispartof: Journal Of Inherited Metabolic Disease vol:s44 issue:1 pages:148-163 ispartof: location:United States status: published

Glycosylation is the most important posttranslational change for proteins. There are more than 100 different types of congenital disorders of glycosylation (CDG). The most frequent is PMM2-CDG with over 700 patients described. N-Linked glycosylation starts from the cytoplasm through the endoplasmic reticulum to the Golgi apparatus, leading to CDG-I and CDG-II defects, respectively. Secretory N-glycosylation abnormalities can be demonstrated by transferrin isoelectric focusing (the screening test for most CDG types). There are also congenital O-linked, combined and lipid-linked glycosylation defects. Clinically, there is often multisystem involvement or a neurologic phenotype. Multiple abnormalities are usually present by routine laboratory analysis (e.g. increased serum transaminases, decreased coagulation factors and endocrine anomalies). Aetiologic treatment is limited to a handful of CDG (mannose supplementation for MPI-CDG and galactose for PGM1-CDG). The mainstay is supportive care. Twenty percent of patients with PMM2-CDG die within 2 years; once the age of 4 year is reached, chances for survival rise dramatically. Key Concepts Glycosylation is essential for the normal function of glycosylated proteins (and lipids), and plays a role in many biologic processes such as endocrine regulation, coagulation, immunity, cell–cell interaction and organogenesis. From the different types of glycosylation defects, N-linked glycosylation defects are the most common and lead to an easily detectable, mostly multisystem disease. Serum transferrin isoelectric focusing detects the missing negative charges of sialic acid in almost all secretory N-linked glycosylation defects. Tissue-specific O-linked glycosylation defects and GPI-anchor-linked glycosylation defects are mostly recognisable syndromes diagnosed by genetic diagnostic methods. The most common CDG type, PMM2-CDG, shows a phenotype of inverted nipples, abnormal fat pads, strabismus, hypotonia and feeding difficulties from a few months of age. Congenital anomalies are relatively common in CDG, including cerebellar vermis hypoplasia, eye malformations, cardiac defects, abnormal fat distribution, skeletal dysplasia, arachnodactyly or cleft palate. Specific treatment is only available for PMI-CDG, namely oral mannose supplementation. Galactose treatment is beneficial for the endocrine, liver and coagulation problems in PGM1-CDG. Keywords: N-glycosylation; transferrin isoelectric focusing; inverted nipples; congenital anomalies; ataxia; seizures; developmental delay; cutis laxa; liver disease; thrombosis

Matrix metalloproteinases (MMPs) are secreted as proenzymes, containing propeptides that interact with the catalytic zinc, thereby controlling MMP activation. The MMP‐9 propeptide is unique in the MMP family because of its post‐translational modification with an N‐linked oligosaccharide. ProMMP‐9 activation by MMP‐3 occurs stepwise by cleavage of the propeptide in an aminoterminal (pro‐AT) and carboxyterminal (pro‐CT) peptide. We chemically synthesized aglycosyl pro‐AT and pro‐CT and purified recombinant glycosylated pro‐ATS f−9. First, we report new cleavage sites in the MMP‐9 propeptide by MMP‐3 and neutrophil elastase. Additionally, we demonstrated with the use of western blot analysis a higher resistance of glycosylated versus aglycosyl pro‐AT against proteolysis by MMP‐3, MMP‐9, meprin α, neutrophil elastase and by protease‐rich synovial fluids from rheumatoid arthritis patients. Moreover, we investigated the effect of glycosylation on proteolytic activation of human proMMP‐9 with the use of zymography and dye‐quenched gelatin cleavage analysis. Compared to recombinant Sf‐9 proMMP‐9 glycoforms, larger oligosaccharides of human neutrophil proMMP‐9 increased resistance against proteolytic activation. Additionally, proMMP‐9 from Congenital Disorder of Glycosylation patients, compared to healthy controls, showed a higher activation rate by MMP‐3. Finally, we demonstrated that glycan‐galectin‐3 interactions reduced proMMP‐9 activation. In conclusion, modification of MMP‐9 propeptide glycosylation is a fine‐tuning mechanism and co‐determines the specific activity of MMP‐9 in physiology and pathology. Enzymes MMP‐9 EC 3.4.24.35, MMP‐3 EC 3.4.24.17, meprin α EC 3.4.24.18, neutrophil elastase EC 3.4.21.37, trypsin EC 3.4.21.4 and PNGase F EC 3.5.1.52., Matrix metalloproteinases (MMPs) contain propeptides that interact with the catalytic zinc, thereby controlling MMP activation. The MMP‐9 propeptide (green) is unique within the MMP family having an N‐linked oligosaccharide (purple). We showed that MMP‐9 propeptide glycosylation itself and galectin‐3 (pink) binding are fine‐tuning mechanisms of the proteolytic activation process, by MMP‐3 (cyan), thereby co‐determining the specific activity of MMP‐9.

Background and Aim: Congenital portosystemic veno-venous malformations are rare abnomalities that often remain undiagnosed. Typically they are classified by their anatomi- cal characteristics according to Morgan (extrahepatic, Abernethy malformations type Ia,b and II) and Park (intrahepatic, types 1-4). However, their clinical presentation is less dependent on the anatomical type. Method: We reviewed the clinical characteristics of six cases drawn from our files (from 1970 to 2006). Results: One patient, a 25-year-old male, had extrahepatic shunting whereby the liver receives only arterial blood because the portal vein (PV) connects with the inferior caval vein (ICV) (Abernethy Ib); he presented with episodes of jaundice and pruritus. Three patients had extrahepatic shunting with patent intrahepatic portal veins, but with shunting of splenomesenterial blood towards the ICV (Abernethy II); these included a 66-year-old male with hepatic encephalopathy, a 17-year-old female with (porto?-)pulmonary hyper- tension without portal hypertension, and a 33-year-old female with epidsodes of acute pain secondary to spontaneous bleeding within a primary liver tumor. Two patients had intra- hepatic shunting; these included an 8-year-old boy who was diagnosed incidentally during work-up for abnormal liver enzymes with a communication between right PV and ICV (Park type 1), and a 59-year-old male with multiple PV-ICV-shunts in several liver segments (Park, type 4) who presented with hepatic encephalopathy. Conclusion: Patients often present with signs of hepatic shunting (encephalopathy, pul- monary hypertension, hepatopulmonary syndrome, and/or hypoglycemia) with relative sparing of the synthetic liver function in the absence of portal hypertension. Some shunts present with space-occupying lesions (focal nodular hyperplasia, hepatocellular carcinoma, nodular regenerative hyperplasia, etc.) or biliary atresia. Finally, some cases are detected incidentally.

Summary: Purpose: Several studies have reported favorable effects of intravenous immunoglobulins (IVIG) in refractory epilepsy. Evidence substantiating an immunomodulatory action is scarce. In an open-label study, we prospectively investigated the effect of IVIG on clinical, EEG and serum/CSF immunological parameters in patients with refractory childhood-onset epilepsy. Methods: Thirteen patients (median age 6.9 years; range 1.6–25.8) with refractory seizures despite 3–4 antiepileptic drug regimens were given IVIG (Sandoglobulin, ZLB-Behring, add-on, 4 × 400 mg/kg/3 weeks). Seizure frequency, 24-h video-EEG, and CSF/serum immunological parameters and cytokine profiles (IL-6/IL-8/IL-12/IL-10) were documented before and after completion of the course. Results: Seizure frequency was reduced by ≥50% in four, and by 25%–50% in three patients. In contrast, variation in automatically recorded spike counts (1-h-wake and -sleep) did not correlate with clinical improvement. Serum immunological parameters showed variable deviations in eight patients (e.g., IgG2 deficiency) and CSF immunoblotting showed oligoclonal bands in two patients. Blood–brain barrier permeability was normal in 12 patients. IL-6 and IL-8 were clearly detectable in CSF of all patients; the levels were significantly higher than those in plasma but remained unaffected by IVIG treatment. Conclusions: Despite unchanged EEG spike counts, substantial reductions in seizure frequency occurred in 7 of 13 patients, suggesting that IVIG hinder progression of central epileptic activity into clinical seizures. Intrathecal presence of IL-8 and IL-6 was documented in all patients, but was unaffected by IVIG, suggesting that their production is directly related to electrical seizure activity and that IVIG may act through interference with immune pathways downstream to IL-6 and IL-8.

A 6-month-old girl with normal psychomotor development presented with fulminant hepatitis. Interestingly, liver biopsy demonstrated features of autoimmune hepatitis, whereas autoantibodies and raised immunoglobulin G (IgG) were absent. There was extensive centrolobular necrosis with bridging (Fig. 1a) and ductular reaction (Fig. 1b). There were numerous lymphocytes and plasmocytes (polyclonal on kappa and lambda stain) (Fig. 1c). Biochemical investigations excluded alternative causes of fulminant hepatitis. Steroid treatment was started, but the patient soon evolved to liver failure and received a liver transplantation. Three months posttransplant, the patient developed myoclonic and generalized tonic-clonic fits. Computed tomography (CT) scan, normal at presentation, revealed evolution toward severe brain atrophy. Mitochondrial assays on postmortem muscle biopsy revealed normal activity of respiratory chain complex II and decreased I, III, and IV activity. This is indicative of mitochondrial DNA (mtDNA) depletion in this clinical setting (Hargreaves et al. 2002). DNA analysis revealed two known POLG mutations (p.Ala467Thr and p. Gly848Ser), diagnostic for Alpers syndrome. We show here for the first time that a mtDNA-depletion syndrome can present with the anatomopathological features of autoimmune hepatitis. Alpers syndrome therefore should not be excluded from the differential diagnostic list based on these features. Whether this is also the case in older children, or even adults, presenting with cryptogenic acute liver failure and pathological features of autoimmune hepatitis remains to be determined.