Jan Peter Rake

Glycogen storage disease type I: diagnosis, management, clinical course and outcome. Results of the European study on glycogen storage disease type I (ESGSD I)

Abstract. Glycogen storage disease type I (GSD I) is a relatively rare metabolic disease and therefore, no metabolic centre has experience of large numbers of patients. To document outcome, to develop guidelines about (long-term) management and follow-up, and to develop therapeutic strategies, the collaborative European Study on GSD I (ESGSD I) was initiated. This paper is an descriptive analysis of data obtained from the retrospective part of the ESGSD I. Included were 231 GSD Ia and 57 GSD Ib patients. Median age of data collection was 10.4 years (range 0.4–45.4 years) for Ia and 7.1 years (0.4–30.6 years) for Ib patients. Data on dietary treatment, pharmacological treatment, and outcome including mental development, hyperlipidaemia and its complications, hyperuricaemia and its complications, bleeding tendency, anaemia, osteopenia, hepatomegaly, liver adenomas and carcinomas, progressive renal disease, height and adult height, pubertal development and bone maturation, school type, employment, and pregnancies are presented. Data on neutropenia, neutrophil dysfunction, infections, inflammatory bowel disease, and the use of granulocyte colony-stimulating factor are presented elsewhere (Visser et al. 2000, J Pediatr 137:187–191; Visser et al. 2002, Eur J Pediatr DOI 10.1007/s00431-002-1010-0). Conclusion: there is still wide variation in methods of dietary and pharmacological treatment of glycogen storage disease type I. Intensive dietary treatment will improve, but not correct completely, clinical and biochemical status and fewer patients will die as a direct consequence of acute metabolic derangement. With ageing, more and more complications will develop of which progressive renal disease and the complications related to liver adenomas are likely to be two major causes of morbidity and mortality.

Glycogen storage disease type Ia: recent experience with mutation analysis, a summary of mutations reported in the literature and a newly developed diagnostic flowchart

Abstract We studied the glucose-6-phosphatase (G6Pase) gene of 30 unrelated glycogen storage disease type Ia (GSD Ia) patients using single strand conformational polymorphism (SSCP) prior to automated sequencing of exons revealing an aberrant SSCP pattern. In all patients we could identify mutations on both alleles of the G6Pase gene, indicating that this method is a reliable procedure. A total of 14 different mutations were identified. R83C (16/60), 158delC (12/60), Q347X (7/60), R170X (6/60) and ΔF327 (4/60) were found most frequently. Nine other mutations accounted for the other 15 mutant alleles. Two DNA-based prenatal diagnoses were performed successfully. At present, 56 mutations in the G6Pase gene have been reported in 300 unrelated GSD Ia patients and an overview of these mutations is presented. Evidence for a clear genotype-phenotype correlation could be established neither from our data nor from those in the literature. With increased knowledge about the genetic basis of GSD Ia and GSD Ib and the high detection rate of mutations, it is our opinion that the diagnoses GSD Ia and GSD Ib can usually be based on clinical and biochemical abnormalities combined with mutation analysis instead of enzyme assays in liver tissue obtained by biopsy. A newly developed flowchart for the diagnosis of GSD I is presented. Conclusion Increased knowledge of the genetic basis of glycogen storage disease type I provides a DNA-based diagnosis, prenatal DNA-based diagnosis in chorionic villus samples and carrier detection.

The Glycogen Storage Diseases and Related Disorders

The liver glycogen storage disorders (GSDs) comprise GSD I, the hepatic presentations of GSD III, GSD IV, GSD VI, the liver forms of GSD IX, and GSD 0. GSD I, III, VI, and IX present similarly with hypoglycemia, marked hepatomegaly, and growth retardation. GSD I is the most severe affecting both glycogen breakdown and gluconeogenesis. In GSD Ib there is additionally a disorder of neutrophil function. Most patients with GSD III have a syndrome that includes hepatopathy, myopathy, and often cardiomyo pathy. GSD VI and GSD IX are the least severe: there is only a mild tendency to fasting hypoglycemia, liver size normalises with age, and patients reach normal adult height. GSD IV manifests in most patients in infancy or childhood as hepatic failure with cirrhosis leading to end-stage liver disease. GSD 0 presents in infancy or early childhood with fasting hypoglycemia and ketosis and, in contrast, with postprandial hyperglycemia and hyperlactatemia. Treatment is primarily dietary and aims to prevent hypoglycemia and suppress secondary metabolic decompensation. This usually requires frequent feeds by day, and in GSD I and in some patients with GSD III, continuous nocturnal gastric feeding.

Renal Function in Glycogen Storage Disease Type I, Natural Course, and Renopreservative Effects of ACE Inhibition

BACKGROUND AND OBJECTIVES Renal failure is a major complication in glycogen storage disease type I (GSD I). We studied the natural course of renal function in GSD I patients. We studied differences between patients in optimal and nonoptimal metabolic control and possible renoprotective effects of angiotensin converting enzyme inhibition. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Thirty-nine GSD I patients that visited our clinic were studied. GFR and effective renal plasma flow (ERPF) were measured by means of I(125) iothalamate and I(131) hippuran clearance and corrected for body surface area. Microalbuminuria was defined as >2.5 mg albumin/mmol creatinine and proteinuria as >0.2 g protein per liter. Optimal metabolic control was present when blood glucoses were >3.5 mmol/L, urine lactate/creatinine ratios <0.06 mmol/mmol, triglycerides <6.0 mmol/L, and uric acid concentrations <450 micromol/L. RESULTS Quadratic regression analysis showed a biphasic pattern in the course of GFR and ERPF related to age. Microalbuminuria was observed significantly less frequently in the patients with optimal metabolic control compared with the patients with nonoptimal metabolic control. A significant decrease in GFR was observed after starting ACE inhibition. CONCLUSIONS This study describes a biphasic pattern of the natural course of GFR and ERPF in GSD I patients, followed by the development of microalbuminuria and proteinuria. Optimal metabolic control has a renoprotective effect on the development of microalbuminuria and proteinuria in GSD I patients. Treatment with ACE inhibitors significantly decreases the GFR, especially in GSD I patients with glomerular hyperfiltration.

Intestinal function in glycogen storage disease type I

Glycogen storage disease type I (GSD I) (McKusick 232200) is caused by inherited defects of the glucose-6-phosphatase complex. Patients with GSD Ia as well as patients with GSD Ib may suffer from intermittent diarrhoea, which seems to worsen with age. The cause of this diarrhoea is unknown. This study describes the results of investigations of intestinal functions and morphology in patients with GSD Ia and GSD Ib, which were performed to detect a common cause for chronic diarrhoea in GSD I. The following were investigated: faecal fat excretion, faecal α1-antitrypsin and faecal chymotrypsin, expiratory H2 concentrations, persorption of cornstarch in urine and colonic biopsies. With the investigations presented in this study, no common cause for diarrhoea in GSD I was found. In GSD Ib loss of mucosal barrier function due to inflammation, documented by increased faecal α1-antitrypsin excretion (3.5–9.6 mg/g dry faeces) and inflammation in the colonic biopsies, seems to be the main cause. The inflammation is most likely related to disturbed neutrophil function, which is often found in GSD Ib. Whether another cause is involved in GSD Ia and in GSD Ib, related to the disturbed function of glucose-6-phosphatase in the enterocyte, remains to be investigated.

Is glycogen storage disease 1a associated with atherosclerosis

Abstract. Deficiency of microsomal glucose-6-phosphatase in liver and kidney leads to glycogen storage disease type 1a (GSD 1a). Notwithstanding intensive dietary therapy, moderate to severe dyslipidaemia and microalbuminuria, both known atherosclerotic risk factors, remain present. Although more patients reach adult age, no information is still available about accelerated atherosclerosis. The aim of our study was to investigate whether GSD 1a was associated with premature atherosclerosis. In nine adolescent patients (mean age 22.7±3.4 years) and nine matched healthy control subjects, lipid profile, blood pressure, ankle-brachial indices, aortic distensibility and intima-media thickness (IMT) of the carotid and femoral arteries were determined. As expected, lipid profiles were significantly unfavourable in the patient group compared with the control group. No differences were found in blood pressure, ankle-brachial indices and aortic distensibility between both groups. IMT segments were comparable in both groups, with even thinner segments in the patient group. In different multivariate models, GSD 1a remained an independent predictor for a thinner IMT (R2=0.90; β=–0.69; P=0.018). Conclusion: glycogen storage disease type 1a is not associated with premature atherosclerosis, despite the existence of longstanding dyslipidaemia and microalbuminuria.

End-stage liver disease as the only consequence of a mitochondrial respiratory chain deficiency: no contra-indication for liver transplantation

Abstract The prerequisite for liver transplantation as a therapeutic option for inherited metabolic diseases should be that the enzyme defect, being responsible for the major clinical (hepatic and/or extra-hepatic) abnormalities, is localised in the liver. Furthermore, no adequate dietary or pharmacological treatment should be available or such treatment should have an unacceptable influence on the quality of life. We report an infant, who developed end-stage liver disease with persistent lactic acidaemia in his first months of life. Analysis of the mitochondrial respiratory chain in liver tissue revealed a combined partial complex I and IV deficiency. No extra-hepatic involvement could be demonstrated by careful screening for multiple organ involvement, including analysis of the mitochondrial respiratory chain in muscle tissue and cultured skin fibroblasts. The boy received a reduced size liver graft at the age of 8 months. He recovered successfully. Almost 5 years after transplantation he is in good clinical condition. No clinical or biochemical signs of any organ dysfunction have been demonstrated. The considerations on which basis it was decided that there was no contra-indication to perform liver transplantation in this patient are discussed. Conclusion The possibility of a mitochondrial respiratory chain deficiency should be considered in liver disease of unknown origin prior to liver transplantation. Liver transplantation is a therapeutic option in mitochondrial respiratory chain deficiency-based end-stage liver disease provided that extra-hepatic involvement is carefully excluded.

Bone mineral density in children, adolescents and adults with glycogen storage disease type Ia: a cross-sectional and longitudinal study.

The occurrence of (symptoms related to) osteopenia is a known complication in glycogen storage disease type Ia (GSD Ia) patients. However, only limited information is available about bone mineral density (BMD). Using dual energy x-ray absorptiometry, we studied both cross-sectional and longitudinal lumbar spine areal BMD (BMDareal in g/cm2), areal BMD corrected for delayed bone maturation (BMDbone age in g/cm2), and volumetric BMD (BMDvol in g/cm3). Prepubertal GSD Ia patients (n = 8) had normal BMD (median z-scores BMDareal -0.6, BMDbone age -0.5 and BMDvol - 0.5), whereas adolescent patients (n = 12) and adult patients (n = 9) had significantly reduced BMD (BMDareal -2.3, BMDbone age -1.6, BMDvol -2.0, and BMDareal -1.9, BMDvol-1.5, respectively). Our longitudinal study, showing a stable BMDareal but a trend to a decrease in BMDvol in prepubertal patients during follow-up, did not clarify whether the difference in BMD between prepubertal and adolescent/adult patients reflects a diminished accretion of BMD during childhood or reflects historica l differences in treatment. In adolescent and adult GSD Ia patients, BMDareal and BMDvol were reduced but stable during follow-up. Especially patients with delayed bone maturation were at risk for reduced BMD. No correlation between parameters of metabolic control and BMD could be detected. Daily calcium intake was within recommended allowances ranges. Abnormal biochemical results included hypomagnesaemia (29%), hypercalciuria (34%) and reduced tubular resorption of phosphate (21%).Although the underlying pathophysiology of reduced BMD in GSD Ia remains unsolved, metabolic control should be optimized to correct as much as possible metabolic and endocrine abnormalitie s that may influence both bone matrix formation and bone mineral accretion.

Pregnancies in glycogen storage disease type Ia.

OBJECTIVE Reports on pregnancies in women with glycogen storage disease type Ia (GSD-Ia) are scarce. Because of improved life expectancy, pregnancy is becoming an important issue. We describe 15 pregnancies by focusing on dietary treatment, biochemical parameters, and GSD-Ia complications. STUDY DESIGN Carbohydrate requirements (milligrams per kilogram per minute), triglyceride and uric acid levels, liver ultrasonography, and creatinine clearance were investigated before, during, and after pregnancy. Data from the newborn infants were obtained from the records. RESULTS In the first trimester, a significant increase in carbohydrate requirements was observed (P = .007). Most patients had acceptable triglyceride and uric acid levels during pregnancy. No increase in size or number of adenomas was seen. In 3 of 4 patients, a decrease in glomerular filtration rate was observed after pregnancy. In 3 pregnancies, lactic acidosis developed during delivery with severe multiorgan failure in 1. All but 1 of the children are healthy and show good psychomotor development. CONCLUSION Successful pregnancies are possible in patients with GSD-Ia, although specific GSD-Ia-related risks are present.

Identification of a Novel Mutation (867delA) in the Glucose-6-phosphatase Gene in Two Siblings with Glycogen Storage Disease Type Ia with Different Phenotypes

We identified a novel mutation (867delA) in the glucose‐6‐phosphatase gene of two siblings with glycogen storage disease type Ia. Although both siblings share the same mutations, their phenotype regarding adult height and hepatomegaly differs. In glycogen storage disease type Ia, substantial heterogeneity in phenotype is observed. So far, no evidence for a clear genotype‐phenotype correlation has been found. Hum Mutat 15:381, 2000.