Guidelines for management of glycogen storage disease type I- European Study on Glycogen Storage Disease Type I(ESGSD I). Eur J Pediatr. 2002;161 Suppl 1:S112-S119. [PMID: 12373584 DOI: 10.1007/bf02680007]

Continuous glucose monitoring metrics in people with liver glycogen storage disease and idiopathic ketotic hypoglycemia: A single-center, retrospective, observational study

BACKGROUND

Cohort data on continuous glucose monitoring (CGM) metrics are scarce for liver glycogen storage diseases (GSDs) and idiopathic ketotic hypoglycemia (IKH). The aim of this study was to retrospectively describe CGM metrics for people with liver GSDs and IKH.

PATIENTS AND METHODS

CGM metrics (descriptive, glycemic variation and glycemic control parameters) were calculated for 47 liver GSD and 14 IKH patients, categorized in cohorts by disease subtype, age and treatment status, and compared to published age-matched CGM metrics from healthy individuals. Glycemic control was assessed as time-in-range (TIR; ≥3.9 - ≤7.8 and ≥3.9 - ≤10.0 mmol/L), time-below-range (TBR; <3.0 mmol/L and ≥3.0 - ≤3.9 mmol/L), and time-above-range (TAR; >7.8 and >10.0 mmol/L).

RESULTS

Despite all patients receiving dietary treatment, GSD cohorts displayed significantly different CGM metrics compared to healthy individuals. Decreased TIR together with increased TAR were noted in GSD I, GSD III, and GSD XI (Fanconi-Bickel syndrome) cohorts (all p < 0.05). In addition, all GSD I cohorts showed increased TBR (all p < 0.05). In GSD IV an increased TBR (p < 0.05) and decreased TAR were noted (p < 0.05). In GSD IX only increased TAR was observed (p < 0.05). IKH patient cohorts, both with and without treatment, presented CGM metrics similar to healthy individuals.

CONCLUSION

Despite dietary treatment, most liver GSD cohorts do not achieve CGM metrics comparable to healthy individuals. International recommendations on the use of CGM and clinical targets for CGM metrics in liver GSD patients are warranted, both for patient care and clinical trials.

Diabetes in a Patient with Glycogen Storage Disease Type 1a

Glycogen storage disease type 1a (GSD-1a) is a rare congenital disease. Recently, life expectancy with GSD-1a has been improved by its early diagnosis and management. Complications of diabetes with GSD-1a are extremely rare. The optimal treatment for glucose control using this disease combination remains unclear. The existence of GSD-1a and diabetes can cause both hypoglycemia and hyperglycemia, making glucose control especially problematic. In the present report, α-glucosidase inhibitor (α-GI) and dipeptidyl peptidase-4 (DPP-4) inhibitors improved hyperglycemia without symptoms of hypoglycemia in a patient with diabetes and GSD-1a using intermittent continuous glucose monitoring (isCGM).

Potential use of other starch sources in the treatment of glycogen storage disease type Ia - an in vitro study

BACKGROUND

Glycogen storage disease type Ia (GSD-Ia) is one of the most common hepatic GSD. Its treatment mainly consists of a diet including a high intake of slow-digestion carbohydrates such as raw cornstarch and the restriction of simple sugars. This enables the maintenance of euglycemia and prevents secondary metabolic disorders. Starch is a glucose polymer formed by amylose and amylopectin, which can be obtained from distinct sources. Although uncooked cornstarch has been successfully used in the treatment of GSD-Ia, it can lead to hyperglycemia and weight gain. in vitro andin vivo tests indicated that sweet manioc starch can be potentially used in the treatment of GSD-Ia.

RESULTS

The moisture analysis revealed a variation from 10.3 to 12.8% in the sweet manioc starch samples, whereas the moisture content of uncooked cornstarch ranged from 7.3 to 11.1%. Quantifiable sugar was detected in 3/5 samples of sweet manioc starch and 1/3 samples of uncooked cornstarch. Notably, this uncooked cornstarch brand is widely employed in GSD-Ia treatment in Brazil. Products B and E had higher values of amylopectin and undetectable levels of sugars. A clinical trial is warranted to compare samples F and G and determine the impact of sugar trace in the same dietary source of starch.

CONCLUSIONS

Collectively, the results demonstrated possible therapeutic alternatives for GSD-Ia in addition to traditional uncooked cornstarch.

Medium-Chain Triglyceride Oil and Dietary Intervention Improved Body Composition and Metabolic Parameters in Children with Glycogen Storage Disease Type 1 in Jordan: A Clinical Trial

Glycogen storage diseases (GSDs) are a group of carbohydrate metabolism disorders, most of which are inherited in autosomal recessive patterns. GSDs are of two types: those that have to do with liver and hypoglycaemia (hepatic GSDs) and those that are linked to neuromuscular presentation. This study aims to assess the impact of dietary intervention, including medium-chain triglyceride (MCT) oil, on anthropometric measurements, body composition analysis and metabolic parameters among Jordanian children and is expected to be the first in the country. A sample of 38 children with glycogen storage disease type 1 (GSD-1) (median age = 6.4 years) were on a diet that included uncooked cornstarch therapy and a fructose-, sucrose- and lactose-restricted diet. Patients started to take MCT oil along with the prescribed diet after the first body composition test. Patients' nutritional status was re-evaluated three months later. The study results show that the percentage of patients who suffered from hypoglycaemia at the beginning of the study decreased significantly from 94.7% to 7.9% (p < 0.0001). The serum levels of triglycerides, cholesterol, uric acid and lactate decreased significantly after three months of intervention (100-71.1%, 73.7-21.1%, 97.4-52.6% and 94.7-18.4%, respectively). In contrast, there was no statistical difference in neutrophil count. Regarding clinical parameters, liver span was significantly reduced from (16.01 ± 2.65 cm) to (14.85 ± 2.26 cm) (p < 0.0001). There were significant improvements in growth parameters, including height-for-age and BMI-for-age for children aged ≥2 years (p = 0.034 and p = 0.074, respectively). Significant improvements in skeletal muscle mass and bone mineral content were also noticed at the end of the trial (p ≤ 0.05). In conclusion, medium-chain triglyceride therapy is found to improve biochemical and growth parameters in children with GSD-1 in Jordan.

Severe perioperative lactic acidosis in a pediatric patient with glycogen storage disease type Ia: a case report

BACKGROUND

Glycogen storage disease (GSD) is a group of rare inherited metabolic disorders caused by enzyme deficiencies in glycogen catabolism. GSD type Ia is a congenital deficiency of the enzyme responsible for the final step in glucose production by glycolysis, resulting in impaired carbohydrate metabolism.

CASE PRESENTATION

A 14-year-old boy with GSD type Ia was scheduled for a maxillary cystectomy under general anesthesia. He was taking oral sugars such as uncooked cornstarch regularly to prevent hypoglycemia. Perioperatively, glucose was administered via the peripheral vein for fasting; however, severe lactic acidosis occurred. He also developed hypercapnia because of intraoperative poor ventilation caused by hepatomegaly.

CONCLUSIONS

We experienced a child with GSD type Ia who developed severe lactic acidosis despite continuous glucose infusion. Further studies are required to determine appropriate perioperative management for patients with GSD, including fasting glucose administration.

Assessment of the diagnosis, treatment, and follow-up of a group of Turkish pediatric glycogen storage disease type 1b patients with varying clinical presentations and a novel mutation

OBJECTIVES

Glycogen storage disease (GSD) type 1b is a multisystemic disease in which immune and infectious complications are present, different from GSD type 1a. Treatment with granulocyte-colony stimulating factor (G-CSF) is often required in the management of neutropenia and inflammatory bowel disease. Recently, an alternative treatment option to G-CSF has been preferred, like empagliflozin. To report on the demographics, genotype, clinical presentation, management, and complications of pediatric patients with glycogen storage disease type 1b (GSD 1b).

METHODS

A retrospective analysis of the clinical course of eight patients with GSD type 1b whose diagnosis was confirmed by molecular testing.

RESULTS

The mean age at referral was four months. The diagnosis of GSD 1b was based on clinical and laboratory findings and supported by genetic studies. One patient presented with an atypical clinical finding in the form of hydrocephalus at the time of first admission. The first symptom was abscess formation on the scalp due to neutropenia in another patient. Other patients had hypoglycemia at the time of admission. All patients presented suffered from neutropenia, which was managed with G-CSF, except one. Hospitalizations for infections were frequent. One patient developed chronic diarrhea and severe infections, which have been brought under control with empagliflozin.

CONCLUSIONS

Neutropenia is an essential finding in GSD 1b and responsible for complications. The coexistence of hypoglycemia and neutropenia should bring to mind GSD 1b. Empagliflozin can be a treatment option for neutropenia, which is resistant to G-CSF treatment.

Glycogen storage diseases

Glycogen storage diseases (GSDs) are a group of rare, monogenic disorders that share a defect in the synthesis or breakdown of glycogen. This Primer describes the multi-organ clinical features of hepatic GSDs and muscle GSDs, in addition to their epidemiology, biochemistry and mechanisms of disease, diagnosis, management, quality of life and future research directions. Some GSDs have available guidelines for diagnosis and management. Diagnostic considerations include phenotypic characterization, biomarkers, imaging, genetic testing, enzyme activity analysis and histology. Management includes surveillance for development of characteristic disease sequelae, avoidance of fasting in several hepatic GSDs, medically prescribed diets, appropriate exercise regimens and emergency letters. Specific therapeutic interventions are available for some diseases, such as enzyme replacement therapy to correct enzyme deficiency in Pompe disease and SGLT2 inhibitors for neutropenia and neutrophil dysfunction in GSD Ib. Progress in diagnosis, management and definitive therapies affects the natural course and hence morbidity and mortality. The natural history of GSDs is still being described. The quality of life of patients with these conditions varies, and standard sets of patient-centred outcomes have not yet been developed. The landscape of novel therapeutics and GSD clinical trials is vast, and emerging research is discussed herein.

Mitochondrial reprogramming in peripheral blood mononuclear cells of patients with glycogen storage disease type Ia

BACKGROUND

Glycogen storage disease type Ia (GSDIa) is an inborn metabolic disorder caused by the deficiency of glucose-6-phospatase-α (G6Pase-α) leading to mitochondrial dysfunction. It remains unclear whether mitochondrial dysfunction is present in patients' peripheral blood mononuclear cells (PBMC) and whether dietary treatment can play a role. The aim of this study was to investigate mitochondrial function in PBMC of GSDIa patients.

METHODS

Ten GSDIa patients and 10 age-, sex- and fasting-time matched controls were enrolled. Expression of genes involved in mitochondrial function and activity of key fatty acid oxidation (FAO) and Krebs cycle proteins were assessed in PBMC. Targeted metabolomics and assessment of metabolic control markers were also performed.

RESULTS

Adult GSDIa patients showed increased CPT1A, SDHB, TFAM, mTOR expression (p < 0.05) and increased VLCAD, CPT2 and citrate synthase activity in PBMC (p < 0.05). VLCAD activity directly correlated with WC (p < 0.01), BMI (p < 0.05), serum malonycarnitine levels (p < 0.05). CPT2 activity directly correlated with BMI (p < 0.05).

CONCLUSION

Mitochondrial reprogramming is detectable in PBMC of GSDIa patients. This feature may develop as an adaptation to the liver enzyme defect and may be triggered by dietary (over)treatment in the frame of G6Pase-α deficiency. PBMC can represent an adequate mean to assess (diet-induced) metabolic disturbances in GSDIa.

Towards values-based healthcare for inherited metabolic disorders: An overview of current practices for persons with liver glycogen storage disease and fatty acid oxidation disorders

Value-based healthcare (VBHC) intends to achieve better outcomes for patients, to improve quality of patient care, with reduced costs. Four dimensions define a model of intimately related value-pillars: personal value, allocative value, technical value, and societal value. VBHC is mostly applied in common diseases, and there are fundamental challenges in applying VBHC strategies to low volume, high complex healthcare situations, such as rare diseases, including inherited metabolic disorders. This article summarizes current practices at various academical domains (i.e., research, healthcare, education, and training) that (aim to) increase values at various value-pillars for persons with liver glycogen storage diseases or fatty acid oxidation disorders and their families. Future perspectives may include facilitating virtual networks to function as integrated practice units, improving measurement of outcomes, and creating information technology platforms to overcome the ethical, legal, societal, and technical challenges of data sharing for healthcare and research purposes.

A Prospective Study on Continuous Glucose Monitoring in Glycogen Storage Disease Type Ia: Toward Glycemic Targets

CONTEXT

Although previous research has shown the benefit of continuous glucose monitoring (CGM) for hepatic glycogen storage diseases (GSDs), current lack of prospectively collected CGM metrics and glycemic targets for CGM-derived outcomes in the hepatic GSD population limits its use.

OBJECTIVE

To assess CGM metrics for glycemic variation and glycemic control in adult patients with GSDIa as compared to matched healthy volunteers.

DESIGN

Prospective CGM data were collected during the ENGLUPRO GSDIa trial (NCT04311307) in which a Dexcom G6 device was used. Ten adult patients with GSDIa and 10 age-, sex- and body mass index-matched healthy volunteers were enrolled. Capillary blood glucose was concurrently measured during 2 standardized 2-hour time intervals. Descriptive [eg, glycemic variability (GV), time below range, time in range (TIR), time above range (TAR)] and advanced (ie, first- and second-order derivatives, Fourier analysis) CGM outcomes were calculated. For each descriptive CGM outcome measure, 95% CIs were computed in patients with GSDIa and healthy volunteers, respectively.

RESULTS

CGM overestimation was higher under preprandial and level 1 hypoglycemia (ie, capillary glucose values ≥ 3.0 mmol/L and < 3.9 mmol/L) conditions. GV and TAR were higher while TIR was lower in patients with GSDIa compared to healthy volunteers (P < 0.05). Three patients with GSDIa showed descriptive CGM outcomes outside the calculated 95% CI in GSDIa patients. Advanced CGM analysis revealed a distinct pattern (ie, first- and second-order derivatives and glucose curve amplitude) in each of these 3 patients within the patients group.

CONCLUSIONS

This is the first study to prospectively compare CGM outcomes between adult patients with GSDIa and matched healthy volunteers. The generation of a set of CGM metrics will provide guidance in using and interpreting CGM data in GSDIa and will be useful for the definition of glycemic targets for CGM in patients with GSDIa. Future studies should investigate the prognostic value of CGM outcomes and their major determinants in patients with GSDIa.

Increased atherosclerosis in a mouse model of glycogen storage disease type 1a

Glycogen storage disease type 1a (GSD Ia) is an inborn error of carbohydrate metabolism. Despite severe hyperlipidemia, GSD Ia patients show limited atherogenesis compared to age-and-gender matched controls. Employing a GSD Ia mouse model that resembles the severe hyperlipidemia in patients, we here found increased atherogenesis in GSD Ia. These data provide a rationale for investigating atherogenesis in GSD Ia in a larger patient cohort.

Understanding the role of SGLT2 inhibitors in glycogen storage disease type Ib: the experience of one UK centre

BACKGROUND

Glycogen storage disease type Ib (GSD Ib) is a severe disorder of carbohydrate metabolism due to bi-allelic variants in SLC37A4. It is associated with neutropaenia and neutrophil dysfunction, which has recently been attributed to the accumulation of 1,5-anhydroglucitol-6-phosphate (1,5AG6P) within neutrophils. Treatment with sodium-glucose co-transporter-2 (SGLT2) inhibitors, such as empagliflozin, is a novel therapy that reduces 1,5-anhydroglucitol (1,5AG) in plasma.

RESULTS

We report our experience in treating 8 paediatric GSD Ib patients with empagliflozin with a cumulative treatment time greater than 12 years. Treatment with a median dose of 5 mg (0.22 mg/kg height weight) of empagliflozin resulted in improvement in bowel health, growth, and laboratory parameters. Plasma 1,5AG levels reduced by a median of 78%. Baseline 1,5AG levels in our cohort were higher than in adult patients with GSD Ib. Hypoglycaemia on empagliflozin treatment occurred in 50% of our cohort.

CONCLUSION

We report the largest single centre cohort of GSD Ib patients treated with empagliflozin to date. Treatment with SGLT2 inhibitors is a novel and favourable treatment option for neutropaenia and neutrophil dysfunction in GSD Ib. We suggest a low starting dose of empagliflozin with careful titration due to the risk of hypoglycaemia. The interpretation of 1,5AG levels and their role in treatment monitoring is yet to be established, and requires ongoing research.

High childhood serum triglyceride concentrations associate with hepatocellular adenoma development in patients with glycogen storage disease type Ia

Background & Aims

Glycogen storage disease type Ia (GSDIa) is an inborn error of carbohydrate metabolism caused by pathogenic variants in the glucose-6-phosphatase catalytic subunit 1 (G6PC1) gene and is associated with hepatocellular adenoma (HCA) formation. Data on risk factors for HCA occurrence in GSDIa are scarce. We investigated HCA development in relation to sex, G6PC1 genotype, and serum triglyceride concentration (TG).

Methods

An observational study of patients with genetically confirmed GSDIa ≥12 years was performed. Patients were categorised for sex; presence of 2, 1, or 0 predicted severe G6PC1 variant (PSV); and median TG during childhood (<12 years; stratified for above/below 5.65 mmol/L, i.e. 500 mg/dl).

Results

Fifty-three patients (23 females) were included, of which 26 patients developed HCA at a median (IQR) age of 21 (17–25) years. At the age of 25 years, 48% of females and 30% of males had developed HCA (log-rank p = 0.045). Two-thirds of patients with GSDIa carried 2 PSVs, 20% carried 1, and 13% carried none. Neither the number of PSVs nor any specific G6PC1 variants were associated with HCA occurrence. Childhood TG was 3.4 (3.0–4.2) mmol/L in males vs. 5.6 (4.0–7.9) mmol/L in females (p = 0.026). Childhood TG >5.65 mmol/L was associated with HCA development at younger age, compared with patients with childhood TG <5.65 mmol/L (18 vs. 33 years; log-rank p = 0.001). Cox regression analysis including TG, sex, and TG–sex interaction correction revealed childhood TG >5.65 mmol/L as an independent risk factor for HCA development (hazard ratio [HR] 6.0; 95% CI 1.2–29.8; p = 0.028).

Conclusions

In patients with GSDIa, high childhood TG was associated with an increased risk of HCA, and earlier onset of HCA development, independent of sex-associated hypertriglyceridaemia, and G6PC1 genotype.

Lay summary

Glycogen storage disease type Ia (GSDIa) is a rare, inherited metabolic disease that can be complicated by liver tumours (hepatocellular adenomas), which in turn may cause bleeding or progress to liver cancer. Risk factors associated with hepatocellular adenoma formation in patients with GSDIa are largely unknown. In our study, we found that high serum triglyceride concentrations during childhood, but not specific genetic variants, were associated with increased risk of hepatocellular adenoma diagnosis later in life.

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Glycogen storage disease Ia (GSDIa) is a metabolic disease caused by mutations in glucose-6-phosphatase catalytic subunit 1 (G6PC1).

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Patients with GSDIa often develop hepatocellular adenoma (HCA), with unclear risk factors.

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Metabolic control in GSDIa is commonly evaluated through serum triglyceride concentration (TG).

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Patients with GSDIa with high childhood TG had increased risk and earlier onset of HCA.

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Sex-associated hypertriglyceridaemia and G6PC1 genotype were not associated with HCA.

Untargeted plasma metabolomics identifies broad metabolic perturbations in glycogen storage disease type I

BACKGROUND

The metabolic defect in glycogen storage disease type I (GSDI) results in fasting hypoglycemia and typical secondary metabolic abnormalities (eg, hypertriglyceridemia, hyperlactatemia, hyperuricemia). The aim of this study was to assess further perturbations of the metabolic network in GSDI patients under ongoing treatment.

METHODS

In this prospective observational study, plasma samples of 14 adult patients (11 GSDIa, 3 GSDIb. Mean age 26.4 years, range 16-46 years) on standard treatment were compared to a cohort of 31 healthy controls utilizing ultra-high performance liquid chromatography (UHPLC) in combination with high resolution tandem mass spectrometry (HR-MS/MS) and subsequent statistical multivariate analysis. In addition, plasma fatty acid profiling was performed by GC/EI-MS.

RESULTS

The metabolomic profile showed alterations of metabolites in different areas of the metabolic network in both GSD subtypes, including pathways of fuel metabolism and energy generation, lipids and fatty acids, amino acid and methyl-group metabolism, the urea cycle, and purine/pyrimidine metabolism. These alterations were present despite adequate dietary treatment, did not correlate with plasma triglycerides or lactate, both parameters typically used to assess the quality of metabolic control in clinical practice, and were not related to the presence or absence of complications (ie, nephropathy or liver adenomas).

CONCLUSION

The metabolic defect of GSDI has profound effects on a variety of metabolic pathways in addition to the known typical abnormalities. These alterations are present despite optimized dietary treatment, which may contribute to the risk of developing long-term complications, an inherent problem of GSDI which appears to be only partly modified by current therapy.

Clinical features of gout in adult patients with type Ia glycogen storage disease: a single-centre retrospective study and a review of literature

Background

This study aimed to explore the clinical features of gout in adult patients with glycogen storage disease type Ia (GSD Ia).

Methods

Ninety-five adult patients with GSD Ia admitted to Peking Union Medical College Hospital were retrospectively analysed. A clinical diagnosis of GSD Ia was confirmed in all patients through gene sequencing. All patients had hyperuricaemia; 31 patients complicated with gout were enrolled, and 64 adult GSD Ia patients with asymptomatic hyperuricaemia were selected as a control group during the same period. Clinical characteristics were analysed and compared between the two groups.

Results

Thirty-one of the 95 patients had complications of gout (median age, 25 years; 11 (35.5%) females). All 31 patients had hepatomegaly, abnormal liver function, fasting hypoglycaemia, hyperuricaemia, hyperlipaemia, and hyperlacticaemia. A protuberant abdomen, growth retardation, recurrent epistaxis, and diarrhoea were the most common clinical manifestations. Among these 31 patients, 10 patients (32.3%) had gout as the presenting manifestation and were diagnosed with GSD Ia at a median time of 5 years (range, 1–14) after the first gout flare. The median age of gout onset was 18 years (range, 10–29). Fifteen of the 31 GSD Ia-related gout patients were complicated with gouty tophi, which has an average incidence time of 2 years after the first gouty flare. The mean value of the maximum serum uric acid (SUA) was 800.5 μmol/L (range, 468–1068). The incidence of gout in adult GSD Ia patients was significantly associated with the initial age of regular treatment with raw corn starch, the proportion of urate-lowering therapy initiated during the asymptomatic hyperuricaemic stage, maximum SUA level, and mean cholesterol level.

Conclusions

Determination of GSD Ia should be performed for young-onset gout patients with an early occurrence of gouty tophi, especially in patients with hepatomegaly, recurrent hypoglycaemia, or growth retardation. Early detection and long-term regulatory management of hyperuricaemia, in addition to early raw corn starch and lifestyle intervention, should be emphasized for GSD Ia patients in order to maintain good metabolic control.

Trial registration

Retrospectively registered.

A retrospective study of eating and psychosocial problems in patients with hepatic glycogen storage diseases and idiopathic ketotic hypoglycemia: Towards a standard set of patient-reported outcome measures

There is a paucity in literature on eating and psychosocial problems in patients with hepatic glycogen storage disease (GSD) and idiopathic ketotic hypoglycemia (IKH), problems that can greatly affect quality of life. This is a monocentre, retrospective, observational mixed method study of patients with hepatic GSD or IKH treated at the Beatrix Children's Hospital Groningen, who had been referred to SeysCentra, a specialist centre for the treatment of eating problems. Additionally, a systematic literature review has been performed to identify instruments to quantify patient-reported outcome measures of psychosocial problems in hepatic GSD patients. Sixteen patients from 12 families were included with ages ranging between 3 and 24 years. Five out of sixteen patients were diagnosed with Avoidant/Restrictive Food Intake Disorder and six patients showed characteristics of this disorder. Fourteen patients experienced sleeping problems, and 11 out of 12 parent couples experienced stress about the illness of their child. We subsequently identified 26 instruments to quantify patient-reported outcome measures for GSD patients. This study demonstrates that GSD patients can develop Avoidant/Restrictive Food Intake Disorder influencing quality of life at multiple domains. The identification of instruments to assess psychosocial wellbeing is an important step towards a standard set of patient-reported outcome measures.

Hepatocyte-specific glucose-6-phosphatase deficiency disturbs platelet aggregation and decreases blood monocytes upon fasting-induced hypoglycemia

OBJECTIVE

Glycogen storage disease type 1a (GSD Ia) is a rare inherited metabolic disorder caused by mutations in the glucose-6-phosphatase (G6PC1) gene. When untreated, GSD Ia leads to severe fasting-induced hypoglycemia. Although current intensive dietary management aims to prevent hypoglycemia, patients still experience hypoglycemic events. Poor glycemic control in GSD Ia is associated with hypertriglyceridemia, hepatocellular adenoma and carcinoma, and also with an increased bleeding tendency of unknown origin.

METHODS

To evaluate the effect of glycemic control on leukocyte levels and coagulation in GSD Ia, we employed hepatocyte-specific G6pc1 deficient (L-G6pc-/-) mice under fed or fasted conditions, to match good or poor glycemic control in GSD Ia, respectively.

RESULTS

We found that fasting-induced hypoglycemia in L-G6pc-/- mice decreased blood leukocytes, specifically proinflammatory Ly6Chi monocytes, compared to controls. Refeeding reversed this decrease. The decrease in Ly6Chi monocytes was accompanied by an increase in plasma corticosterone levels and was prevented by the glucocorticoid receptor antagonist mifepristone. Further, fasting-induced hypoglycemia in L-G6pc-/- mice prolonged bleeding time in the tail vein bleeding assay, with reversal by refeeding. This could not be explained by changes in coagulation factors V, VII, or VIII, or von Willebrand factor. While the prothrombin and activated partial thromboplastin time as well as total platelet counts were not affected by fasting-induced hypoglycemia in L-G6pc-/- mice, ADP-induced platelet aggregation was disturbed.

CONCLUSIONS

These studies reveal a relationship between fasting-induced hypoglycemia, decreased blood monocytes, and disturbed platelet aggregation in L-G6pc-/- mice. While disturbed platelet aggregation likely accounts for the bleeding phenotype in GSD Ia, elevated plasma corticosterone decreases the levels of proinflammatory monocytes. These studies highlight the necessity of maintaining good glycemic control in GSD Ia.

A generic emergency protocol for patients with inborn errors of metabolism causing fasting intolerance: A retrospective, single-center study and the generation of www.emergencyprotocol.net

Patients with inborn errors of metabolism causing fasting intolerance can experience acute metabolic decompensations. Long-term data on outcomes using emergency letters are lacking. This is a retrospective, observational, single-center study of the use of emergency letters based on a generic emergency protocol in patients with hepatic glycogen storage diseases (GSD) or fatty acid oxidation disorders (FAOD). Data on hospital admissions, initial laboratory results, and serious adverse events were collected. Subsequently, the website www.emergencyprotocol.net was generated in the context of the CONNECT MetabERN eHealth project following multiple meetings, protocol revisions, and translations. Representing 470 emergency protocol years, 127 hospital admissions were documented in 54/128 (42%) patients who made use of emergency letters generated based on the generic emergency protocol. Hypoglycemia (here defined as glucose concentration < 3.9 mmol/L) was reported in only 15% of hospital admissions and was uncommon in patients with ketotic GSD and patients with FAOD aged >5 years. Convulsions, coma, or death was not documented. By providing basic information, emergency letters for individual patients with hepatic GSD or the main FAOD can be generated at www.emergencyprotocol.net, in nine different languages. Generic emergency protocols are safe and easy for home management by the caregivers and the first hour in-hospital management to prevent metabolic emergencies in patients with hepatic GSD and medium-chain Acyl CoA dehydrogenase deficiency. The website www.emergencyprotocol.net is designed to support families and healthcare providers to generate personalized emergency letters for patients with hepatic GSD and the main FAOD.

A retrospective in-depth analysis of continuous glucose monitoring datasets for patients with hepatic glycogen storage disease: Recommended outcome parameters for glucose management

Continuous glucose monitoring (CGM) systems have great potential for real-time assessment of glycemic variation in patients with hepatic glycogen storage disease (GSD). However, detailed descriptions and in-depth analysis of CGM data from hepatic GSD patients during interventions are scarce. This is a retrospective in-depth analysis of CGM parameters, acquired in a continuous, real-time fashion describing glucose management in 15 individual GSD patients. CGM subsets are obtained both in-hospital and at home, upon nocturnal dietary intervention (n = 1), starch loads (n = 11) and treatment of GSD Ib patients with empagliflozin (n = 3). Descriptive CGM parameters, and parameters reflecting glycemic variation and glycemic control are considered useful CGM outcome parameters. Furthermore, the combination of first and second order derivatives, cumulative sum and Fourier analysis identified both subtle and sudden changes in glucose management; hence, aiding assessment of dietary and medical interventions. CGM data interpolation for nocturnal intervals reduced confounding by physical activity and diet. Based on these analyses, we conclude that in-depth CGM analysis can be a powerful tool to assess glucose management and optimize treatment in individual hepatic GSD patients.

Crohn disease-like enterocolitis remission after empagliflozin treatment in a child with glycogen storage disease type Ib: a case report

BACKGROUND

Besides major clinical/biochemical features, neutropenia and inflammatory bowel disease (IBD) constitute common complications of Glycogen storage disease type Ib (GSD Ib). However, their management is still challenging. Although previous reports have shown benefit of empagliflozin administration on neutropenia, no follow-up data on bowel (macro/microscopic) morphology are available. We herein present for the first time longitudinal assessment of bowel morphology in a GSD Ib child suffering from Crohn disease-like enterocolitis treated with empagliflozin.

CASE PRESENTATION

A 14-year-old boy with GSD Ib and severe IBD was (off-label) treated with empagliflozin (20 mg/day) after informed oral and written consent was obtained from the patient's parents. No adverse events were noted. Clinical symptoms and stool frequency improved within the first week of treatment. Pediatric Crohn disease activity index (PCDAI) normalised within the first month of treatment. Abdomen magnetic resonance imaging (MRI) performed 3 months after treatment initiation showed dramatic decrease in disease activity and length. Similar findings were reported on histology at 5.5 months. At 7.5 months hemoglobin levels normalised and fecal calprotectin almost normalised. Improved neutrophil count, metabolic control and quality of life were also noted. G-CSF dose was decreased by 33% and the patient was partly weaned from tube feeding.

CONCLUSIONS

This is the first report presenting extensive gastrointestinal morphology follow-up in a GSD Ib patient receiving empagliflozin. The present case suggests that empagliflozin can be safe and effective in inducing IBD remission in GSD Ib patients and can even postpone surgery. Future studies are required to confirm its effect over time and assess its benefit in various disease stages. The development of an international collaborating networks for systematic data collection is worthy.

Impaired Very-Low-Density Lipoprotein catabolism links hypoglycemia to hypertriglyceridemia in Glycogen Storage Disease type Ia

Prevention of hypertriglyceridemia is one of the biomedical targets in Glycogen Storage Disease type Ia (GSD Ia) patients, yet it is unclear how hypoglycemia links to plasma triglyceride (TG) levels. We analyzed whole-body TG metabolism in normoglycemic (fed) and hypoglycemic (fasted) hepatocyte-specific glucose-6-phosphatase deficient (L-G6pc^-/- ) mice. De novo fatty acid synthesis contributed substantially to hepatic TG accumulation in normoglycemic L-G6pc^-/- mice. In hypoglycemic conditions, enhanced adipose tissue lipolysis was the main driver of liver steatosis, supported by elevated free fatty acid concentrations in GSD Ia mice and GSD Ia patients. Plasma very-low-density lipoprotein (VLDL) levels were increased in GSD Ia patients and in normoglycemic L-G6pc^-/- mice, and further elevated in hypoglycemic L-G6pc^-/- mice. VLDL-TG secretion rates were doubled in normo- and hypoglycemic L-G6pc^-/- mice, while VLDL-TG catabolism was selectively inhibited in hypoglycemic L-G6pc^-/- mice. In conclusion, fasting-induced hypoglycemia in L-G6pc^-/- mice promotes adipose tissue lipolysis and arrests VLDL catabolism. This mechanism likely contributes to aggravated liver steatosis and dyslipidemia in GSD Ia patients with poor glycemic control and may explain clinical heterogeneity in hypertriglyceridemia between GSD Ia patients.

The natural history of glycogen storage disease type Ib in England: A multisite survey

Glycogen storage disease type Ib (GSDIb) is characterized by hepatomegaly and fasting hypoglycaemia as well as neutropaenia and recurrent infections. We conducted a retrospective observational study on a cohort of patients with GSDIb across England. A total of 35 patients, with a median age of 9.1 years (range 1-39 years), were included in the study. We examined the genotype and phenotype of all patients and reported 14 novel alleles. The phenotype of GSDIb in England involves a short fasting tolerance that extends into adulthood and a high prevalence of gastrointestinal symptoms. Growth is difficult to manage and neutropaenia and recurrent infections persist throughout life. Liver transplantation was performed in nine patients, which normalized fasting tolerance but did not correct neutropaenia. This is the first natural history study on the cohort of GSDIb patients in England.

ANTHROPOMETRIC AND DIETARY ASSESSMENT OF PATIENTS WITH GLYCOGENOSIS TYPE I

Objective:

To perform anthropometric and dietary evaluation of patients with glycogenosis type Ia and Ib.

Methods:

This cross-sectional study is composed of a sample of 11 patients with glycogenosis divided into two subgroups according to the classification of glycogenosis (type Ia=5 and type Ib=6), aged between 4 and 20 years. The analyzed anthropometric variables were weight, height, body mass index, and measures of lean and fat body mass, which were compared with reference values. For dietary assessment, a food frequency questionnaire was used to calculate energy and macronutrients intake as well as the amount of raw cornstarch consumed. Mann-Whitney U test and Fisher’s exact test were performed, considering a significance level of 5%.

Results:

Patients ingested raw cornstarch in the amount of 0.49 to 1.34 g/kg/dose at a frequency of six times a day, which is lower than recommended (1.75-2.50 g/kg/dose, four times a day). The amount of energy intake was, on average, 50% higher than energy requirements; however, carbohydrate intake was below the adequacy percentage in 5/11 patients. Short stature was found in 4/10 patients; obesity, in 3/11; and muscle mass deficit, in 7/11. There were no statistical differences between the subgroups.

Conclusions:

In patients with glycogenosis type I, there was deficit in growth and muscle mass, but no differences were found between the subgroups (Ia and Ib). Although the diet did not exceed the adequacy of carbohydrates, about 1/3 of the patients presented obesity, probably due to higher energy intake.

Nutrition in Chronic Liver Disease: Consensus Statement of the Indian National Association for Study of the Liver

Malnutrition and sarcopenia are common in patients with chronic liver disease and are associated with increased risk of decompensation, infections, wait-list mortality and poorer outcomes after liver transplantation. Assessment of nutritional status and management of malnutrition are therefore essential to improve outcomes in patients with chronic liver disease. This consensus statement of the Indian National Association for Study of the Liver provides a comprehensive review of nutrition in chronic liver disease and gives recommendations for nutritional screening and treatment in specific clinical scenarios of malnutrition in cirrhosis in adults as well as children with chronic liver disease and metabolic disorders.

Preclinical Research in Glycogen Storage Diseases: A Comprehensive Review of Current Animal Models

GSD are a group of disorders characterized by a defect in gene expression of specific enzymes involved in glycogen breakdown or synthesis, commonly resulting in the accumulation of glycogen in various tissues (primarily the liver and skeletal muscle). Several different GSD animal models have been found to naturally present spontaneous mutations and others have been developed and characterized in order to further understand the physiopathology of these diseases and as a useful tool to evaluate potential therapeutic strategies. In the present work we have reviewed a total of 42 different animal models of GSD, including 26 genetically modified mouse models, 15 naturally occurring models (encompassing quails, cats, dogs, sheep, cattle and horses), and one genetically modified zebrafish model. To our knowledge, this is the most complete list of GSD animal models ever reviewed. Importantly, when all these animal models are analyzed together, we can observe some common traits, as well as model specific differences, that would be overlooked if each model was only studied in the context of a given GSD.

Dietary lipids in glycogen storage disease type III: A systematic literature study, case studies, and future recommendations

A potential role of dietary lipids in the management of hepatic glycogen storage diseases (GSDs) has been proposed, but no consensus on management guidelines exists. The aim of this study was to describe current experiences with dietary lipid manipulations in hepatic GSD patients. An international study was set up to identify published and unpublished cases describing hepatic GSD patients with a dietary lipid manipulation. A literature search was performed according to the Cochrane Collaboration methodology through PubMed and EMBASE (up to December 2018). All delegates who attended the dietetics session at the IGSD2017, Groningen were invited to share unpublished cases. Due to multiple biases, only data on GSDIII were presented. A total of 28 cases with GSDIII and a dietary lipid manipulation were identified. Main indications were cardiomyopathy and/or myopathy. A high fat diet was the most common dietary lipid manipulation. A decline in creatine kinase concentrations (n = 19, P < .001) and a decrease in cardiac hypertrophy in paediatric GSDIIIa patients (n = 7, P < .01) were observed after the introduction with a high fat diet. This study presents an international cohort of GSDIII patients with different dietary lipid manipulations. High fat diet may be beneficial in paediatric GSDIIIa patients with cardiac hypertrophy, but careful long-term monitoring for potential complications is warranted, such as growth restriction, liver inflammation, and hepatocellular carcinoma development.

Incidental detection of Corynebacterium jeikeium endocarditis via regular blood examination in an afebrile hemodialysis patient

Herein, we describe a rare case of Corynebacterium jeikeium endocarditis that silently progressed in a 65-year-old man undergoing hemodialysis. Because routine monthly blood examination revealed high C-reactive protein levels, blood cultures were collected, although he had no symptom and was afebrile. After 2 days, a Gram-positive rod was detected in one set of the blood culture. Furthermore, transthoracic echocardiography revealed new aortic regurgitation (AR) and vegetations, and, therefore, infective endocarditis was suspected. Transesophageal echocardiography showed vegetations with a maximum diameter of 8 mm on his aortic valve, with some valve destruction. C. jeikeium was identified in three sets of blood cultures. Administration of daptomycin was started because he had vancomycin allergy. Judging from the high risk of embolization due to vegetations, emergency aortic valve replacement was performed on the second day. C. jeikeium was detected in a resected cardiac valve specimen and blood. This case emphasizes that physicians should always consider the possibility of infective endocarditis even in hemodialysis patients without any symptoms.

Dietary Management of the Glycogen Storage Diseases: Evolution of Treatment and Ongoing Controversies

The hepatic glycogen storage diseases (GSDs) are a group of disorders where abnormal storage or release of glycogen leads to potentially life-threatening hypoglycemia and metabolic disturbances. Dietary interventions have markedly improved the outcome for these disorders, from a previously fatal condition to one where people can do well with proper care. This article chronicles the evolution of dietary management and treatment of the hepatic GSDs (types 0, I, III, VI, IX, and XI). We examine historic and current approaches for preventing hypoglycemia associated with GSDs. There is a lack of consensus on the optimal dietary management of GSDs despite decades of research, and the ongoing controversies are discussed.

Cornstarch requirements of the adult glycogen storage disease Ia population: A retrospective review

Cornstarch has been the primary treatment for glycogen storage disease type Ia (GSD Ia) for over 35 years. When cornstarch was first described as a treatment, few people survived beyond early childhood. As the prognosis for this population has improved, the need to ensure appropriate cornstarch dosing for different age groups has become imperative. Records from 115 patients (10-62 years of age) with GSD Ia evaluated at our center between 2015 and 2017 were reviewed. Data collected included weight, age, genetic mutation, amount and frequency of cornstarch doses, body mass index, gender, 24-hour glucose and lactate concentrations, and biochemical markers of metabolic control. The data demonstrate that adult treatment needs vary greatly from younger age groups, and the required cornstarch support decreases with age (P < .001). The required number of doses, however, did not change with a mean of six doses (range 4-8) daily in all age groups. General laboratory findings across time demonstrate that significantly reducing the amount of starch required to maintain euglycemia with aging can be done without sacrificing metabolic control. Carbohydrate requirements decrease with aging, and older patients were found to require less cornstarch. Failure to lower the cornstarch doses contributes to over-treatment in adults with GSD Ia. Not only does this lead to worsening hepatomegaly and excessive weight gain, but over-treatment contributes to relative hyperinsulinism and rebound hypoglycemia. This knowledge is essential in designing nutritional therapies for the aging GSD population.

Predominance of the c.648G > T G6PC gene mutation and late complications in Korean patients with glycogen storage disease type Ia

BACKGROUND

Glycogen storage disease (GSD) Ia, caused by mutations in the glucose-6-phosphatase (G6PC) gene, is characterized by hepatomegaly, hypoglycemia, lactic acidosis, dyslipidemia, and hyperuricemia. This study aimed to investigate clinical and molecular features and late complications in Korean patients with GSD Ia.

RESULTS

Fifty-four Korean patients (33 males and 21 females) from 47 unrelated families, who were diagnosed with GSD Ia, based on genetic and biochemical data, between 1999 and 2017, were included in this study. The median age at diagnosis was 3.9 years (range: 5 months to 42 years), and the follow-up period was 8.0 ± 6.8 years. Most patients presented with hepatomegaly during infancy, but hypoglycemic symptoms were not predominant. Genetic analysis showed that all the patients had at least one c.648G > T allele. Homozygous c.648G > T mutations in the G6PC gene were identified in 34 families (72.3%), and compound heterozygotes with c.648G > T were found in the other families. The allele frequency of c.648G > T was 86.2% (81/94), and p.F51S, p.R83H, p.G122D, p.Y128*, p.G222R, and p.T255A were identified. Of 26 adult patients, 14 had multiple hepatic adenomas, and two were diagnosed with hepatocellular carcinoma. Thirteen patients showed renal complications, and seven patients presented gout, despite preventive allopurinol treatment. Twelve patients had osteoporosis, and two patients had pulmonary hypertension. The final heights were 157.9 cm (standard deviation score: - 3.1) in males and 157.8 cm (standard deviation score: - 0.6) in females.

CONCLUSION

In our Korean patients with GSD Ia, the most common mutation in the G6PC gene was c.648G > T, suggesting a founder effect. Because of only mild hypoglycemia, the patients tended to be diagnosed late. Thus, adult patients with GSD Ia eventually developed diverse and serious complications, which indicates a need for careful monitoring and proper management of this disease.

Use of waxy maize heat modified starch in the treatment of children between 2 and 5 years with glycogen storage disease type I: A retrospective study

Background

Glycogen storage disease type I (GSDI) is caused by deficiency of the enzyme glucose-6-phosphatase or glucose-6-phosphate transporter. Mainstay of treatment is provision of uncooked cornstarch (and/or continuous nocturnal pump feed (CNPF) to maintain normoglycemia). Waxy maize heat modified starch (WMHMS) is another treatment option to maintain normoglycemia overnight. Our objective was to describe our experience treating children 2–5 years of age with GSDI using WMHMS overnight.

Method

This is a retrospective case series review (n = 5) comparing the overnight feeding regimen and biochemical control one year before and after nocturnal WMHMS therapy. The WMHMS trial, in which blood glucose and lactate levels were monitored hourly, is reported in detail.

Results

Most patients successfully transitioned to nocturnal WMHMS feeds. These patients had stable glucose and lactate throughout the overnight period, permitting a fasting period of 6.5–8 h overnight. Within the time period studied, WMHMS appeared to have improved overnight control of blood glucose levels with fewer reported episodes of hypoglycemia compared to CNPF.

Conclusion

WMHMS can be an effective substitute treatment to achieve stable nocturnal glucose control in children younger than five years of age. A larger multicenter prospective study is recommended to establish stronger evidence of the efficacy and safety of using WMHMS in treatment of young children with GSDI.

A Novel Mutation in a Newborn Baby Leading to Glycogen Storage Disease Type Ia

Glycogen storage disease type Ia (GSD1A) is caused by mutations in the G6PC gene. The G6PC gene was first cloned in 1993. Since then, many different mutations have been identified leading to this disease. Hepatomegaly is one of the important clinical manifestations of the disease. A 23-day-old girl was admitted to the hospital due to respiratory distress. Her physical examination was normal except for tachypnea. She had hypoglycemia, lactic academia, hyperlipidemia and hyperuricemia. With these clinical findings, GSD1A was considered in the patient and the diagnosis was genetically confirmed. By direct sequencing of the G6PC gene, we identified a novel homozygous variation (c.137T>G/p.Leu46Arg) in the patient and the healthy mother and father were heterozygotes for the variant. Here we present a case with a novel homozygous missense mutation c.137T>G/p.Leu46Arg in the G6PC gene leading to GSD1A clinical findings except early hepatomegaly. These findings expand the spectrum of causative mutations, and clinical findings in GSD1A.

Delivery of mRNA Therapeutics for the Treatment of Hepatic Diseases

Promising improvements in the field of transcript therapeutics have clearly enhanced the potential of mRNA as a new pillar for protein replacement therapies. Synthetic mRNAs are engineered to replace mutated mRNAs and to be immunologically inconspicuous and highly stable while maximizing protein expression. Approaches to deliver mRNA into the cellular cytoplasm safely and efficiently have been further developed so that two mRNA-based approaches replacing vascular endothelial growth factor (VEGF) and cystic fibrosis transmembrane conductance regulator (CFTR) have now made it into clinical trials. These studies bring mRNA therapeutics for protein replacement therapy closer to clinical realization. Herein, we provide an overview of preclinical and clinical developments of mRNA therapeutics for liver diseases.

Hepatic glycogen storage diseases are associated to microbial dysbiosis

INTRODUCTION

The gut microbiome has been related to several features present in Glycogen Storage Diseases (GSD) patients including obesity, inflammatory bowel disease (IBD) and liver disease.

OBJECTIVES

The primary objective of this study was to investigate associations between GSD and the gut microbiota.

METHODS

Twenty-four GSD patients on treatment with uncooked cornstarch (UCCS), and 16 healthy controls had their faecal microbiota evaluated through 16S rRNA gene sequencing. Patients and controls were ≥3 years of age and not on antibiotics. Faecal pH, calprotectin, mean daily nutrient intake and current medications were recorded and correlated with gut microbiome.

RESULTS

Patients' group presented higher intake of UCCS, higher prevalence of IBD (n = 04/24) and obesity/overweight (n = 18/24) compared to controls (n = 0 and 06/16, respectively). Both groups differed regarding diet (in patients, the calories' source was mainly the UCSS, and the intake of fat, calcium, sodium, and vitamins was lower than in controls), use of angiotensin-converting enzyme inhibitors (patients = 11, controls = 0; p-value = 0.001) multivitamins (patients = 22, controls = 01; p-value = 0.001), and mean faecal pH (patients = 6.23; controls = 7.41; p = 0.001). The GSD microbiome was characterized by low diversity and distinct microbial structure. The operational taxonomic unit (OTU) abundance was significantly influenced by faecal pH (r = 0.77; p = 6.8e-09), total carbohydrate (r = -0.6; p = 4.8e-05) and sugar (r = 0.057; p = 0.00013) intakes.

CONCLUSIONS

GSD patients presented intestinal dysbiosis, showing low faecal microbial diversity in comparison with healthy controls. Those findings might be due to the disease per se, and/or to the different diets, use of UCSS and of medicines, and obesity rate found in patients. Although the main driver of these differences is unknown, this study might help to understand how the nutritional management affects GSD patients.

Glycemic control and complications in glycogen storage disease type I: Results from the Swiss registry

BACKGROUND

Regular carbohydrate intake to avoid hypoglycemia is the mainstay of dietary treatment in glycogen storage disease type I (GSDI). The aim of this study was to evaluate the quality of dietary treatment and glycemic control in a cohort of GSDI patients, in relation to the presence of typical long-term complications.

METHODS

Data of 25 patients (22 GSD subtype Ia and 3 GSDIb, median age 20y) from the Swiss hepatic glycogen storage disease registry was analyzed cross-sectionally. Frequency and type of hypoglycemia symptoms were assessed prospectively using a structured questionnaire. Diagnostic continuous glucose monitoring (CGM) was performed as part of usual clinical care to assess glycemic control in 14 patients, usually once per year with a mean duration of 6.2 ± 1.1 consecutive days per patient per measurement.

RESULTS

Although maintenance of euglycemia is the primary goal of dietary treatment, few patients (n = 3, 13%) performed capillary blood glucose measurements regularly. Symptoms possibly associated with hypoglycemia were present in 13 patients (57%), but CGM revealed periods of low glucose (<4 mmol/l) in all patients, irrespective of the presence of symptoms. GSDIa patients with liver adenomas (n = 9, 41%) showed a higher frequency and area under the curve (AUC) of low blood glucose than patients without adenomas (frequency 2.7 ± 0.8 vs. 1.5 ± 0.7 per day, AUC 0.11 ± 0.08 vs. 0.03 ± 0.02 mmol/l/d; p < 0.05). Similarly, the presence of microalbuminuria was also associated with the frequency of low blood glucose. Z-Scores of bone density correlated negatively with lactate levels.

CONCLUSION

The quality of glucose control is related to the presence of typical long-term complications in GSDI. Many patients experience episodes of asymptomatic low blood glucose. Regular assessment of glucose control is an essential element to evaluate the quality of treatment, and increasing the frequency of glucose self-monitoring remains an important goal of patient education and motivation. CGM devices may support patients to optimize dietary therapy in everyday life.

A preliminary study of telemedicine for patients with hepatic glycogen storage disease and their healthcare providers: from bedside to home site monitoring

BACKGROUND

The purpose of this project was to develop a telemedicine platform that supports home site monitoring and integrates biochemical, physiological, and dietary parameters for individual patients with hepatic glycogen storage disease (GSD).

METHODS AND RESULTS

The GSD communication platform (GCP) was designed with input from software developers, GSD patients, researchers, and healthcare providers. In phase 1, prototyping and software design of the GCP has occurred. The GCP was composed of a GSD App for patients and a GSD clinical dashboard for healthcare providers. In phase 2, the GCP was tested by retrospective patient data entry. The following software functionalities were included (a) dietary registration and prescription module, (b) emergency protocol module, and (c) data import functions for continuous glucose monitor devices and activity wearables. In phase 3, the GSD App was implemented in a pilot study of eight patients with GSD Ia (n = 3), GSD IIIa (n = 1), and GSD IX (n = 4). Usability was measured by the system usability scale (SUS). The mean SUS score was 64/100 [range: 38-93].

CONCLUSIONS

This report describes the design, development, and validation process of a telemedicine platform for patients with hepatic GSD. The GCP can facilitate home site monitoring and data exchange between patients with hepatic GSD and healthcare providers under varying circumstances. In the future, the GCP may support cross-border healthcare, second opinion processes and clinical trials, and could possibly also be adapted for other diseases for which a medical diet is the cornerstone.

Inborn Errors of Metabolism with Hypoglycemia: Glycogen Storage Diseases and Inherited Disorders of Gluconeogenesis

Although hyperinsulinism is the predominant inherited cause of hypoglycemia in the newborn period, inborn errors of metabolism are the primary etiologies after 1 month of age. Disorders of carbohydrate metabolism often present with hypoglycemia when fasting occurs. The presentation, diagnosis, and management of the hepatic glycogen storage diseases and disorders of gluconeogenesis are reviewed.

G6PC mRNA Therapy Positively Regulates Fasting Blood Glucose and Decreases Liver Abnormalities in a Mouse Model of Glycogen Storage Disease 1a

Glycogen storage disease type Ia (GSD1a) is an inherited metabolic disorder caused by the deficiency of glucose-6-phosphatase (G6Pase). GSD1a is associated with life-threatening hypoglycemia and long-term liver and renal complications. We examined the efficacy of mRNA-encoding human G6Pase in a liver-specific G6Pase^−/− mouse model (L-G6PC^−/−) that exhibits the same hepatic biomarkers associated with GSD1a patients, such as fasting hypoglycemia, and elevated levels of hepatic glucose-6-phosphate (G6P), glycogen, and triglycerides. We show that a single systemic injection of wild-type or native human G6PC mRNA results in significant improvements in fasting blood glucose levels for up to 7 days post-dose. These changes were associated with significant reductions in liver mass, hepatic G6P, glycogen, and triglycerides. In addition, an engineered protein variant of human G6Pase, designed for increased duration of expression, showed superior efficacy to the wild-type sequence by maintaining improved fasting blood glucose levels and reductions in liver mass for up to 12 days post-dose. Our results demonstrate for the first time the effectiveness of mRNA therapy as a potential treatment in reversing the hepatic abnormalities associated with GSD1a.

How I manage children with neutropenia

Neutropenia, usually defined as a blood neutrophil count <1·5 × 10⁹ /l, is a common medical problem for children and adults. There are many causes for neutropenia, and at each stage in life the clinical pattern of causes and consequences differs significantly. I recommend utilizing the age of the child and clinical observations for the preliminary diagnosis and primary management. In premature infants, neutropenia is quite common and contributes to the risk of sepsis with necrotizing enterocolitis. At birth and for the first few months of life, neutropenia is often attributable to isoimmune or alloimmune mechanisms and predisposes to the risk of severe bacterial infections. Thereafter when a child is discovered to have neutropenia, often associated with relatively minor symptoms, it is usually attributed to autoimmune disorder or viral infection. The congenital neutropenia syndromes are usually recognized when there are recurrent infections, the neutropenia is severe and there are congenital anomalies suggesting a genetic disorder. This review focuses on the key clinical finding and laboratory tests for diagnosis with commentaries on treatment, particularly the use of granulocyte colony-stimulating factor to treat childhood neutropenia.

Characterisation, in vitro digestibility and expected glycemic index of commercial starches as uncooked ingredients

In this study native starches as ingredients (corn, rice, wheat, tapioca and potato) were characterized for microstructure, physicochemical, functional and thermal properties, in vitro digestibility and glycemic index. There was a significant variation in the granule shape and size distribution of the starches. Particle size monomodal (corn, tapioca, potato) and bimodal (rice, wheat) distribution was observed amongst the starches. The potato starch showed the biggest size granules while the rice showed the smallest. The examined properties and nutritional characteristics of starches were significantly different. Thermal properties were studied using Differential Scanning Calorimeter (DSC). DSC results showed that the transition temperatures (58.8-78.7 °C) and enthalpies of gelatinization (2.3-8.2 J/g) of the starches appeared to be greatly influenced by microstructure and chemical composition (e.g. resistant starch). Nutritional properties such as slowly digestible starch and expected glycemic index values followed the order: rice > wheat > tapioca > corn > potato. In particular, the highest resistant starch was recorded for potato starch.

Liver transplantation for pediatric inherited metabolic disorders: Considerations for indications, complications, and perioperative management

LT is an effective therapeutic option for a variety of IEM. This approach can significantly improve the quality of life of patients who suffer from severe disease manifestations and/or life-threatening metabolic decompensations despite medical/dietary management. Due to the significant risks for systemic complications from surgical stressors, careful perioperative management is vital. Even after LT, some disorders require long-term dietary restriction, medical management, and monitoring of metabolites. Successful liver transplant for these complex disorders can be achieved with disease- and patient-specific strategies using a multidisciplinary approach. In this article, we review indications, complications, perioperative management, and long-term follow-up recommendations for IEM that are treatable with LT.

Alternative nighttime nutrition regimens in glycogen storage disease type I: a controlled crossover study

BACKGROUND

Traditional approaches for nighttime glycemic control in glycogen storage disease type I (GSDI) include continuous tube feeding, or ingestion of uncooked corn starch (CS) at bedtime. A modified corn starch (MCS) has been shown to prolong euglycemia in some patients. The aim of this study was to evaluate whether stable nighttime glucose control can be achieved with other types of slowly digested carbohydrates in adult GSDI patients.

METHODS

In this cross-over study, nocturnal glucose control and fasting times were assessed with three different nocturnal nutrition regimens in five patients, using continuous glucose monitoring (CGMS) in an outpatient everyday life setting. For each patient, continuous glucose profiles were measured after ingestion of (1) CS, (2) MCS or (3) a pasta meal at bedtime, during 5 to 6 consecutive nights for each regimen.

RESULTS

Stable nocturnal glucose control was achieved for all patients with a pasta meal, with a mean duration of glycemia >3.5 mmol/l of 7.6 h (range 5.7-10.8), and >4 mmol/l of 7 h (5.2-9.2), similar to CS and MCS. Fasting glucose before breakfast on workdays (after 7.1 ± 0.8 h) was not significantly different between the three interventions (CS 4.1 ± 0.5 mmol/l, MCS 4.6 ± 0.7 mmol/l, pasta 4.3 ± 0.9 mmol/l). During prolonged fasting on weekends, longer duration of normoglycemia was achieved with CS or MCS than with pasta.

CONCLUSION

Consumption of cooked pasta is a suitable and more palatable alternative to uncooked corn starch to achieve nighttime glucose control in adult patients with GSDI.

Diagnosis and management of glycogen storage disease type I: a practice guideline of the American College of Medical Genetics and Genomics

PURPOSE

Glycogen storage disease type I (GSD I) is a rare disease of variable clinical severity that primarily affects the liver and kidney. It is caused by deficient activity of the glucose 6-phosphatase enzyme (GSD Ia) or a deficiency in the microsomal transport proteins for glucose 6-phosphate (GSD Ib), resulting in excessive accumulation of glycogen and fat in the liver, kidney, and intestinal mucosa. Patients with GSD I have a wide spectrum of clinical manifestations, including hepatomegaly, hypoglycemia, lactic acidemia, hyperlipidemia, hyperuricemia, and growth retardation. Individuals with GSD type Ia typically have symptoms related to hypoglycemia in infancy when the interval between feedings is extended to 3–4 hours. Other manifestations of the disease vary in age of onset, rate of disease progression, and severity. In addition, patients with type Ib have neutropenia, impaired neutrophil function, and inflammatory bowel disease. This guideline for the management of GSD I was developed as an educational resource for health-care providers to facilitate prompt, accurate diagnosis and appropriate management of patients.

METHODS

A national group of experts in various aspects of GSD I met to review the evidence base from the scientific literature and provided their expert opinions. Consensus was developed in each area of diagnosis, treatment, and management.

RESULTS

This management guideline specifically addresses evaluation and diagnosis across multiple organ systems (hepatic, kidney, gastrointestinal/nutrition, hematologic, cardiovascular, reproductive) involved in GSD I. Conditions to consider in the differential diagnosis stemming from presenting features and diagnostic algorithms are discussed. Aspects of diagnostic evaluation and nutritional and medical management, including care coordination, genetic counseling, hepatic and renal transplantation, and prenatal diagnosis, are also addressed.

CONCLUSION

A guideline that facilitates accurate diagnosis and optimal management of patients with GSD I was developed. This guideline helps health-care providers recognize patients with all forms of GSD I, expedite diagnosis, and minimize adverse sequelae from delayed diagnosis and inappropriate management. It also helps to identify gaps in scientific knowledge that exist today and suggests future studies.