Hepatic Glycogen Storage Diseases Research Articles

The relation between dietary polysaccharide intake and urinary excretion of tetraglucoside.

The urinary metabolite tetraglucoside (Glc4) is a potential biomarker for hepatic glycogen storage diseases (GSDs). Glc4 is believed to reflect body glycogen content and/or turnover. However, dietary polysaccharide intake may influence Glc4 excretion, potentially limiting the utility of Glc4 as a monitoring biomarker in hepatic GSDs. We aimed to investigate the association of dietary polysaccharide intake with Glc4 excretion. Urinary Glc4 excretion (mmol/mmol creatinine and mmol/24 h) was analyzed using a validated LC-MS/MS method. Data was analyzed from 65 kidney transplant recipients and 58 healthy kidney donors in the TransplantLines cohort study. Spearman's correlation and multivariable linear regression analyses were performed. In the multivariable analysis, dry lean body mass (DLBM), dietary polysaccharide intake, transplantation status, age, sex, and glycated hemoglobin (HbA1c) served as independent variables. Daily variation was examined in 21 healthy individuals of urinary Glc4 excretion in 2-h collections over a 24-h period. Mixed generalized additive models were built to study the association of prior polysaccharide intake with Glc4 excretion. No (univariate) associations were found between polysaccharide intake and Glc4 excretion. However, a significant interaction between DLBM and polysaccharide on 24 h Glc4 excretion was observed in the multivariate analysis. Glc4 excretion throughout the day exhibited no relationship to prior polysaccharide intake. Our findings suggest an indirect effect of polysaccharide intake on Glc4 excretion, potentially due to changes in muscle glycogen content and/or turnover. We have found no evidence that dietary polysaccharides under normal intakes increase urinary Glc4 directly.

Endocrine Complications in Hepatic Glycogen Storage Diseases: A Long-term Perspective.

Patients with hepatic type of glycogen storage diseases (GSDs) can manifest endocrine features such as hypoglycemia, dyslipidemia, or osteoporosis. This study aimed to investigate the long-term endocrine consequences in patients with hepatic GSDs. This study included 64 patients from 52 families with hepatic GSDs including GSD type Ia (41 patients from 37 families), Ib (3 unrelated), III (8 from 6 families), IV (one patient), and IX (11 from 5 families). All patients were genetically confirmed. Clinical and endocrine findings were retrospectively analyzed. The median age at diagnosis and current age were 2.4 years (range, 0.1-42.4 years) and 17.6 years (range, 1.0-47.8 years), respectively. The mean height SDS at diagnosis was -3.5 ± 1.4, and short stature was observed in 35.6% of patients. Patients diagnosed after the age of 3.4 years exhibited a high risk of short stature (OR = 36.1; P-value < 0.001). Among 33 patients who reached final height, 23 (69.7%) showed delayed puberty. Hypertriglyceridemia was observed in 46 patients (71.9%), whereas 25 patients (39%) had elevated low-density lipoprotein cholesterol levels during the follow-up period. Among 24 patients who underwent dual energy X-ray absorptiometry, 22 showed a low bone mineral density Z-score of -3.0 ± 1.3 at the L-spine. This study described the long-term endocrine consequences in patients with hepatic GSDs. Pediatric endocrinologists should be aware of the presenting features and long-term endocrine sequelae of GSDs to provide proper management and decrease its morbidities.

Short and long-term acceptability and efficacy of extended-release cornstarch in the hepatic glycogen storage diseases: results from the Glyde study

BackgroundHypoglycaemia is the primary manifestation of all the hepatic types of glycogen storage disease (GSD). In 2008, Glycosade®, an extended-release waxy maize cornstarch, was reported as an alternative to uncooked cornstarch (UCCS) which could prolong the duration of fasting in the GSD population. To date, there has been minimal published experience in (a) young children, (b) the ketotic forms of GSD, and (c) with daytime dosing. The Glyde study was created as a prospective, global initiative to test the efficacy and tolerance of Glycosade use across a broader and more diverse population.MethodsA randomised double-blind cross-over fasting study assessing the tolerance and efficacy of Glycosade compared with cornstarch was performed across disease types and ages. Participants and clinicians chose the product deemed superior, whilst still blinded. Participants were followed for 2 years to assess long-term metabolic control, growth, and quality of life.ResultsSixty-one participants (age 2–62 years; 59% female) were enrolled, and 58 participants completed the fasting studies (28 GSD I; 30 GSD III, VI, IX). Glycosade improved duration of fasting in GSD I and duration of fasting without ketosis in the ketotic forms. Chronic Glycosade use was chosen by 69% of participants. Those treated with Glycosade for the 2-year chronic phase used fewer doses of therapy while markers of metabolic control remained stable.ConclusionThe Glyde study is the first multi-centre international trial demonstrating the efficacy and tolerance of Glycosade in a large cohort of hepatic GSD patients across a diverse international population. The ability to use fewer doses of therapy per day and avoidance of overnight therapy may improve compliance, safety, and quality of life without sacrificing metabolic control.

Natural history study of hepatic glycogen storage disease type IV and comparison to Gbe1ys/ys model.

BackgroundGlycogen storage disease type IV (GSD IV) is an ultrarare autosomal recessive disorder that causes deficiency of functional glycogen branching enzyme and formation of abnormally structured glycogen termed polyglucosan. GSD IV has traditionally been categorized based on primary hepatic or neuromuscular involvement, with hepatic GSD IV subclassified as discrete subtypes: classic (progressive) and nonprogressive.MethodsTo better understand the progression of liver disease in GSD IV, we present clinical and histopathology data from 23 patients from around the world and characterized the liver involvement in the Gbe1ys/ys knockin mouse model.ResultsWe propose an alternative to the established subtype-based terminology for characterizing liver disease in GSD IV and recognize 3 tiers of disease severity: (i) "severe progressive" liver disease, (ii) "intermediate progressive" liver disease, and (iii) "attenuated" liver disease. Analysis of liver pathology revealed that risk for liver failure cannot be predicted from liver biopsy findings alone in individuals affected by GSD IV. Moreover, analysis of postmortem liver pathology from an individual who died over 40 years after being diagnosed with nonprogressive hepatic GSD IV in childhood verified that liver fibrosis did not regress. Last, characterization of the liver involvement in a mouse model known to recapitulate the adult-onset neurodegenerative form of GSD IV (Gbe1ys/ys mouse model) demonstrated hepatic disease.ConclusionOur findings challenge the established subtype-based view of GSD IV and suggest that liver disease severity among patients with GSD IV represents a disease continuum.Trial registrationClinicalTrials.gov NCT02683512FundingNone.

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.

Glycogen Storage Disease: Expert Opinion on Clinical Diagnosis Revisited after Molecular Testing.

This study sought to analyze whether an accurate diagnosis of the type and subtype of hepatic Glycogen Storage Diseases (GSDs) could be performed based on general clinical and biochemical aspects via comparing the proposed diagnostic hypotheses with the molecular results. Twelve physicians with experience in hepatic GSDs reviewed 45 real cases comprising a standardized summary of clinical and laboratory data. There was no relation between the hit rate and the time since graduation, the time of experience in GSD, and the number of patients treated during their careers. The average assertiveness was 47%, with GSD Ia and Ib being the best-identified types, while no expert correctly identified GSD IXc. Underage investigation for later manifestations, incomplete clinical description, and complementary analysis, the overvaluation of a specific clinical finding ("false positive") or the discarding of the diagnosis in the absence of it ("false negative"), as well as the lack of knowledge of the rarest GSD types, may have impacted the accuracy of the assessment. This study emphasized that characteristics considered as determinants in identifying the specific types or subtypes of GSD are not exclusive, thus becoming factors that may have induced the evaluators to misdiagnose.

Hepatic ChREBP orchestrates intrahepatic carbohydrate metabolism to limit hepatic glucose 6-phosphate and glycogen accumulation in a mouse model for acute Glycogen Storage Disease type Ib

ObjectiveCarbohydrate Response Element Binding Protein (ChREBP) is a glucose 6-phosphate (G6P)-sensitive transcription factor that acts as a metabolic switch to maintain intracellular glucose and phosphate homeostasis. Hepatic ChREBP is well-known for its regulatory role in glycolysis, the pentose phosphate pathway, and de novo lipogenesis. The physiological role of ChREBP in hepatic glycogen metabolism and blood glucose regulation has not been assessed in detail, and ChREBP's contribution to carbohydrate flux adaptations in hepatic Glycogen Storage Disease type 1 (GSD I) requires further investigation. MethodsThe current study aimed to investigate the role of ChREBP as a regulator of glycogen metabolism in response to hepatic G6P accumulation, using a model for acute hepatic GSD type Ib. The immediate biochemical and regulatory responses to hepatic G6P accumulation were evaluated upon G6P transporter inhibition by the chlorogenic acid S4048 in mice that were either treated with a short hairpin RNA (shRNA) directed against ChREBP (shChREBP) or a scrambled shRNA (shSCR). Complementary stable isotope experiments were performed to quantify hepatic carbohydrate fluxes in vivo. ResultsShChREBP treatment normalized the S4048-mediated induction of hepatic ChREBP target genes to levels observed in vehicle- and shSCR-treated controls. In parallel, hepatic shChREBP treatment in S4048-infused mice resulted in a more pronounced accumulation of hepatic glycogen and further reduction of blood glucose levels compared to shSCR treatment. Hepatic ChREBP knockdown modestly increased glucokinase (GCK) flux in S4048-treated mice while it enhanced UDP-glucose turnover as well as glycogen synthase and phosphorylase fluxes. Hepatic GCK mRNA and protein levels were induced by shChREBP treatment in both vehicle- and S4048-treated mice, while glycogen synthase 2 (GYS2) and glycogen phosphorylase (PYGL) mRNA and protein levels were reduced. Finally, knockdown of hepatic ChREBP expression reduced starch domain binding protein 1 (STBD1) mRNA and protein levels while it inhibited acid alpha-glucosidase (GAA) activity, suggesting reduced capacity for lysosomal glycogen breakdown. ConclusionsOur data show that ChREBP activation controls hepatic glycogen and blood glucose levels in acute hepatic GSD Ib through concomitant regulation of glucose phosphorylation, glycogenesis, and glycogenolysis. ChREBP-mediated control of GCK enzyme levels aligns with corresponding adaptations in GCK flux. In contrast, ChREBP activation in response to acute hepatic GSD Ib exerts opposite effects on GYS2/PYGL enzyme levels and their corresponding fluxes, indicating that GYS2/PYGL expression levels are not limiting to their respective fluxes under these conditions.

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.

Altered gut microbiota and microbial metabolism in children with hepatic glycogen storage disease: a case-control study.

Accumulating evidence has demonstrated that gut microbiota dysbiosis correlated with altered metabolism are implicated in liver metabolic diseases. However, data on pediatric hepatic glycogen storage disease (GSD) are limited. Here, we aimed to investigate the features of the gut microbiota and metabolites in hepatic GSD children from China. Totals of 22 hepatic GSD patients and 16 age- and gender-matched healthy children were enrolled from the Shanghai Children's Hospital, China. Pediatric GSD patients were confirmed as having hepatic GSD via genetic diagnosis and/or liver biopsy pathology. The control group comprised children without any history of chronic diseases or clinically relevant GSD or symptoms of any other metabolic diseases. The baseline characteristics of the two groups were gender- and age-matched matched using chi-squared test and the Mann-Whitney U test, respectively. The gut microbiota, bile acids (BAs), and short chain fatty acids (SCFAs) were determined from the feces using 16S ribosomal RNA (rRNA) gene sequencing, ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), and gas chromatography-mass spectrometry (GC-MS), respectively. The alpha diversity of fecal microbiome was significantly lower in hepatic GSD patients [observed species richness (Sobs): P=0.011; abundance-based coverage estimator (ACE): P=0.011; Chao: P=0.011; Shannon: P<0.001], and their microbial community was more distanced from that of the control [principal coordinate analysis (PCoA) on genus level, unweighted UniFrac: P=0.011]. Relative abundances of phyla Firmicutes (P=0.030) and Bacteroidetes (P=0.029), families Lachnospiraceae (P=0.012), Ruminococcaceae (P=0.008), and Peptostreptococcaceare (P=0.031), genera Blautia (P=0.017), Eubacterium_hallii_group (P=0.032), and Faecalibacterium (P=0.017) were decreased, whereas phyla Actinobacteria (P=0.033), Proteobacteria (P=0.049), families Bifidobacteriaceae (P=0.030), Lactobacillaceae (P=0.034), and Veillonellaceae (P=0.033), genera Lactobacillus (P=0.011), Enterobater (P=0.034), and Veillonella (P=0.014) were increased in hepatic GSD. Altered microbial metabolisms were characterized by increased abundances of primary BAs (P=0.009) and decreased concentrations of SCFAs in hepatic GSD children. Furthermore, the altered bacterial genera were correlated with the changes of both fecal BAs and SCFAs. The hepatic GSD patients in this study presented with gut microbiota dysbiosis which correlated with altered BAs metabolism and fecal SCFAs changes. Further studies are needed to investigate the driver of these changes mediated by either the genetic defect, disease status, or diet therapy.

Cytokine profiling in patients with hepatic glycogen storage disease: Are there clues for unsolved aspects?

Hepatic Glycogen Storage Diseases (GSD) are rare genetic disorders in which the gluconeogenesis pathway is impaired. Cytokines control virtually every aspect of physiology and may help to elucidate some unsolved questions about phenotypes presented by GSD patients. This was an exploratory study in which 27 GSD patients on treatment (Ia=16, Ib=06, III=02, IXα=03) and 24 healthy age- and sex-matched subjects had plasma samples tested for a panel of 20 cytokines (G-CSF,GM-CSF, IL-1α,IL-1β, IL-4, IL-6, IL-8, IL-10, IL-13, IL-17A, GRO, IP-10/CXCL10, MCP-1/CCL2, MIP-1α/CCL3, MIP-1β/CCL4, MDC/CCL22, IFN-γ, TNF-α, TNF-β, VEGF) through a multiplex kit and analyzed in comparison to controls and among patients, regarding to clinical features as anemia, hepatic adenocarcinoma and triglyceride levels. Patients (GSD-Ia/III/IX) presented reduced levels of IL-4 (p=0.040), MIP-1α/CCL3 (p=0.003), MDC/CCL22 (p<0.001), TNF-β (p=0.045) and VEGF (p=0.043) compared to controls. When different types of GSD were compared, G-CSF was higher in GSD-Ib than -Ia (p<0.001) and than -III/IX (p=0.033) patients; IL-10 was higher in GSD-Ib than in GSD-Ia patients (p=0.019); and GSD-III/IX patients had increased levels of IP-10/CXCL10 than GSD-Ib patients (p=0.019). When GSD-I patients were gathered into the same group and compared with GSD-III/IX patients, IP10/CXCL10 and MCP-1 were higher in the latter group (p=0.005 and p=0.013, respectively). GSD-I patients with anemia presented higher levels of IL-4 and MIP-1α in comparison with patients who had not. Triglyceride level was correlated with neutrophil count and MDC levels on GSD-Ia patients without HCA. Altogether, altered levels of cytokines in GSD-I patients reflect an imbalance in immunoregulation process. This study also indicates that neutrophils and some cytokines are affected by triglyceride levels, and future studies on the theme should consider this variable.

Natural history and genotype-phenotype correlation in Hepatic Glycogen Storage Disease in Indian children

Natural history and genotype-phenotype correlation in Hepatic Glycogen Storage Disease in Indian children

Outcome of liver transplantation in hepatic glycogen storage disease: A systematic review and meta-analysis.

Liver transplantation (LT) is the choice of therapeutic option for end-stage hepatic GSD patients; however, reports about the long-term outcome of LT in these patients have remained controversial. We performed a systematic review and meta-analysis of observational studies published until Dec 31, 2021, that investigatedthe long-term outcome of LT in hepatic GSD patients. A literature search in the MEDLINE/PubMed, EMBASE,Cochrane Library, Scopus and Web of Science Core Collection databases was performed. 14 studies with 210 patients were included in our analysis. As the results showed, the pooled proportion of GSD patients with complications after liver transplant (e.g., hemorrhagic shock, biliary complications, tacrolimus encephalopathy, chronic hepatitis, hepatic artery thrombosis, hepatic adenoma, sepsis, liver dysfunction, chronic rejection, acute cellular rejection, and CMV infection) was 27.7% (95% CI: 20.42-35.67) without heterogeneity (I2 =24.04%), as calculated by the random-effect model. The pooled proportion of GSD patients with complications related to GSD after LT, including HCC (Hepatocellular carcinoma), renal complication, muscle problems, delayed menarche, persistent neutropenia, pneumonitis, renal failure, and hepatic adenoma was 22.2% (95% CI: 7.97-40.01) with high heterogeneity (I2 =82.47%). Subgroup analysis including the age of patients (adult/pediatric), duration of follow-up, and type of donor was conducted to investigate the resources of heterogeneity. According to our investigation and review analysis, most GSD patients showed significant outcome improvement after liver transplantation. Overall, our findings showed an excellent outcome of liver transplantation in GSD patients; however, it needs further investigations to be confirmed.

Hepatic Glycogenosis: A Modern Reality in Children with Type 1 Diabetes

Background: Mauriac syndrome (MS) is a rare complication of type 1 diabetes (T1D). It is related to low insulin concentrations and is less common since longer-acting insulins became available. It is characterized by hepatomegaly, growth and puberty delay, and the presence of elevated transaminases and serum lipids. Case reports of patients with Mauriac syndrome are found infrequently in the literature given historic improvements in diabetes management due to readily available insulin therapy. Case: We report a case of Mauriac syndrome diagnosed in a 15-year-old male. The patient maintained poor glycemic control since childhood, presenting glycated hemoglobin persistently higher than 10% and recurrent episodes of ketoacidosis. He was referred for hepatomegaly evolving for 6 months. The clinical examination objectified a distended abdomen with hepatomegaly at 16 cm. Biological examinations showed hyperglycemia, major cytolysis and cholestasis anicteric. Support based on therapeutic education of the child and his family, as well as adequate insulin therapy have been established. The etiological investigation of hepatic disturbances was negative. The clinical and biological evolution was favorable. The diagnosis of hepatic glycogen storage disease was retained on a bundle of anamnestic and clinical arguments, in the absence of other anomalies responsible for the disturbances liverworts. The diagnostic certainty is histological, and the treatment is based on the equilibration of the diabetes. Conclusion: Although MS is an ancient entity described in T1D, it still exists, particularly in adolescent patients. Being aware of MS is of extreme importance since most of the clinical features are reversible with better glycemic control.

Continuous glucose monitoring and nursing of a child with hepatic glycogen storage disease

Continuous glucose monitoring and nursing of a child with hepatic glycogen storage disease

Hepatic glycogen storage diseases type 0, VI and IX: description of an italian cohort

BackgroundGlycogen storage disease (GSD) type 0, VI and IX are inborn errors of metabolism involving hepatic glycogen synthesis and degradation. We performed a characterization of a large Italian cohort of 30 patients with GSD type 0a, VI, IXa, IXb and IXc. A retrospective evaluation of genetical, auxological and endocrinological data, biochemical tests, and nutritional intakes was assessed. Eventual findings of overweight/obesity and insulin-resistance were correlated with diet composition.ResultsSix GSD-0a, 1 GSD-VI, and 23 GSD-IX patients were enrolled, with an age of presentation from 0 to 72 months (median 14 months). Diagnosis was made at a median age of 30 months, with a median diagnostic delay of 11 months and a median follow-up of 66 months. From first to last visit, patients gained a median height of 0.6 SDS (from − 1.1 to 2.1 SDS) and a median weight of 0.5 SDS (from − 2.5 to 3.3 SDS); mean and minimal glucose values significant improved (p < 0.05). With respect to dietary intakes, protein intake (g/kg) and protein intake (g/kg)/RDA ratio directly correlated with the glucose/insulin ratio (p < 0.05) and inversely correlated with HOMA-IR (Homeostasis model assessment of insulin resistance, p < 0.05), BMI SDS (p < 0.05) and %ibw (ideal body weight percentage, p < 0.01).ConclusionA prompt establishment of specific nutritional therapy allowed to preserve growth, improve glycemic control and prevent liver complication, during childhood. Remarkably, the administration of a high protein diet appeared to have a protective effect against overweight/obesity and insulin-resistance.

Body composition in patients with hepatic glycogen storage diseases

ObjectivesThe present study aimed to evaluate the body composition of hepatic glycogen storage disorders (GSDs) through dual energy x-ray absorptiometry. MethodsThis was an exploratory, observational, cross-sectional study. Twenty-four patients with GSD (type Ia: n = 13, Ib: n = 5, III: n = 2, and IX-α/β/γ: n = 4; female sex: n = 13; age <8 y: n = 3, 8–19 y: n = 14, and >19 y: n = 7) were included. Three-day dietary records were collected in the week preceding dual energy x-ray absorptiometry. Body composition findings were correlated with clinical parameters, uncooked cornstarch (UCCS) regimen, dietary intake, and markers of treatment adherence. ResultsAn elevated fat mass (FM) index was found in 16 of 21 patients (age 8–19 y: n = 10 and >19 y: n = 6; GSD type Ia: n = 12, Ib: n = 2, III: n = 1, and IX-γ: n = 1). A lean mass (LM) index evaluation showed no LM deficits in relation to corresponding reference populations. Relative skeletal muscle index values were decreased in 2 of 7 adult patients (type Ib: n = 1 and IX-α: n = 1). UCCS (g/d) correlated positively with the FM index (rs = 0.7; P ≤ 0.01). In contrast, relative UCCS intake (g/kg body weight) was negatively associated with LM/kg (rs = –0.8; P ≤ 0.01). ConclusionsThese findings suggest a high frequency of elevated FM in patients with hepatic GSDs. We also suggest that treatment with UCCS is associated with excess weight in these patients. Additionally, the treatment strategy can impair protein intake, and lead to a decrease in LM.

Beyond predicting diagnosis: Is there a role for measuring biotinidase activity in liver glycogen storage diseases?

IntroductionBiotinidase synthesis is needed to recycle biotin for essential metabolic reactions. Biotinidase activity is lower than normal levels in advanced liver disease but is higher in hepatic glycogen storage disorders (GSDs), however the cause of this association remains unclear. MethodsIn this study, biotinidase activity was measured in plasma samples from 45 individuals with hepatic GSDs; GSDI (a, b; n = 25) and GSD III (a, b; n = 20), complemented by a chart review to associate biotinidase activity levels with clinical laboratory and imaging findings known to be implicated in these GSDs. ResultsOur findings showed variation in biotinidase activity levels among subjects with GSD I and III; biotinidase activity correlated positively with hypertriglyceridemia in subjects with GSD I (r = 0.47, P = 0.036) and GSD III (r = 0.58, P = 0.014), and correlated negatively with age (r = −0.50, P = 0.03) in patients with GSD III. Additionally, biotinidase activity was reduced, albeit within the normal range in subjects with evidence of fibrosis/cirrhosis, as compared to subjects with hepatomegaly with or without steatosis (P = 0.002). DiscussionsThese findings suggest that abnormal lipid metabolism in GSD I and III and progressive liver disease in GSD III may influence biotinidase activity levels. We suggest that a prospective, multi-center, longitudinal study designed to assess the significance of monitoring biotinidase activity in a larger cohort with hepatic GSDs is warranted to confirm this observation. Take-home messageAltered lipid metabolism and advancing liver fibrosis/cirrhosis may influence biotinidase activity levels in patients with hepatic glycogen storage disease. Thus, longitudinal monitoring of biotinidase activity, when combined with clinical and other biochemical findings may be informative.

Assessment of auditory functions in patients with hepatic glycogen storage diseases.

Hepatic glycogen storage diseases are a group of diseases manifesting mainly with hypoglycemia and hepatomegaly. The patients require frequent daytime and nocturnal feedings. Hypoglycemia may cause sensorineural hearing loss and nocturnal feeding is a risk factor for the development of gastroesophageal reflux that may cause chronic otitis media and hearing loss consequently. We aimed to determine the prevalence and characteristics of hearing loss in hepatic glycogen storage diseases. A total of 24 patients with hepatic glycogen storage disease (15 glycogen storage disease type I and 9 non type I) and 24 age/sex matched healthy controls were enrolled in the study. Pure tone audiometer, immitansmetry, acoustic reflex measurement, otoacoustic emission test (OAE) and auditory brainstem response (ABR) tests were applied to all participants. Hearing loss was determined in 17/24 patients (12 glycogen storage disease type I and 5 non type I) with pure tone audiometer. Interpretation of all the findings revealed a total of 8 patients had conductive and 9 had mixed hearing loss. All parameters were significantly different than the control group. This is the first study to comprehensively assess the auditory functions of patients with hepatic glycogen storage disease. Audiological findings determined a significantly increased prevalence of conductive/ mixed type hearing loss in the patient group which is a new finding in the literature. Further studies with extended patient numbers are required to enlighten the underlying pathophysiology.

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.

Bone Mineral Density in Patients with Hepatic Glycogen Storage Diseases.

The association between bone mineral density (BMD) and hepatic glycogen storage diseases (GSDs) is still unclear. To evaluate the BMD of patients with GSD I, IIIa and IXα, a cross-sectional study was performed, including 23 patients (GSD Ia = 13, Ib = 5, IIIa = 2 and IXα = 3; median age = 11.9 years; IQ = 10.9–20.1) who underwent a dual-energy X-ray absorptiometry (DXA). Osteocalcin (OC, n = 18), procollagen type 1 N-terminal propeptide (P1NP, n = 19), collagen type 1 C-terminal telopeptide (CTX, n = 18) and 25-OH Vitamin D (n = 23) were also measured. The participants completed a 3-day food diary (n = 20). Low BMD was defined as a Z-score ≤ −2.0. All participants were receiving uncooked cornstarch (median dosage = 6.3 g/kg/day) at inclusion, and 11 (47.8%) presented good metabolic control. Three (13%) patients (GSD Ia = 1, with poor metabolic control; IIIa = 2, both with high CPK levels) had a BMD ≤ −2.0. CTX, OC and P1NP correlated negatively with body weight and age. 25-OH Vitamin D concentration was decreased in seven (30.4%) patients. Our data suggest that patients with hepatic GSDs may have low BMD, especially in the presence of muscular involvement and poor metabolic control. Systematic nutritional monitoring of these patients is essential.