Glycogen storage disease type I: diagnosis and phenotype/genotype correlation

Glycogen storage disease type Ia (GSD Ia) is caused by mutations in theG6PC gene encoding the phosphatase of the microsomal glucose-6-phosphatase system. GSD Ia is characterized by hepatomegaly, hypoglycemia, lactic acidemia, hyperuricemia, hyperlipidemia and short stature. Other forms of GSD I (GSD I non-a) are characterized by the additional symptom of frequent infections caused by neutropenia and neutrophil dysfunction. GSD I non-a is caused by mutations in a gene encoding glucose-6-phosphatase translocase (G6PT1). We report on the molecular genetic analyses of G6PC and G6PT 1 in 130 GSD Ia patients and 15 GSD I non-a patients, respectively, and provide an overview of the current literature pertaining to the molecular genetics of GSD I. Among the GSD Ia patients, 34 different mutations were identified, two of which have not been described before (A65P; F117C). Seventeen different mutations were detected in the GSD I non-a patients. True common mutations were identified neither in GSD Ia nor in GSD I non-a patients,Conclusion: Glycogen storage disease type Ia and and type I non-a are genetically heterogenous disorders. For the diagnosis of the various forms of glycogen storage disease type I, molecular genetic analyses are reliable and convenient alternatives to the enzyme assays in liver biopsy specimens. Some genotype-phenotype correlations exist, for example, homozygosity for oneG6PC mutation, G188R, seems to be associated with a glycogen storage disease type I non-a phenotype and homozygosity for the 727G>T mutation may be associated with a milder phenotype but an increased risk for hepatocellular carcinoma. Published online: 27 July 2002     

Historical highlights and unsolved problems in glycogen storage disease type 1

Thirty-three years after Von Gierke described the first patient with glycogen storage disease type 1 (GSD1) in 1929, the Coris detected glucose-6-phosphatase (G6Pase) deficiency. The first mutation of this enzyme was identified 41 years later and subsequently the gene was mapped to chromosome 17q21, its enzyme topology defined, a nine transmembrane helical model suggested, an enzyme deficient knockout mouse created and by infusing an adenoviral vector associated murine G6Pase gene, correction of the clinical and laboratory abnormalities was observed. A similar successful gene transfer has been performed in enzyme deficient canine puppies. To explain the function of the G6Pase complex, a multicomponent translocase catalytic model has been proposed in which different transporters shuttle glucose-6-phosphate (G6P), inorganic phosphate (Pi) and glucose across the microsomal membrane. It was suggested that GSD1b patients suffered from a G6P transporter (G6PT) defect and the first mutation in the G6PT gene subsequently recognised. The gene mapped to chromosome 11q23 and its structural organisation was defined which showed a close functional linkage between G6PT and hydrolysis. Nordlie identified the first patient with Pi transport deficiency (GSD1c). However putative GSD1c and 1d patients based on kinetic studies were found to harbour mutations in the G6PT gene so that GSD1 patients are presently divided into 1a and non-1a. G6PT deficient patients suffer from numerical and functional leucocyte defects. A mRNA leucocyte G6PT deficiency has been suggested to account for the glucose phosphorylation and subsequent calcium sequestration defects observed in theses cells. Inflammatory bowel disease which occurs frequently in GSD non-1a patients has been related to their leucocyte abnormalities. Dietary management of GSD1 patients, designed to maintain a normal blood glucose level can be achieved during the night by nocturnal gastric infusions of glucose-containing solution or by the administration of uncooked cornstarch around the clock or by a combination of both. Both therapeutic modalities, if conducted in a meticulous manner, have a major impact on the quality of life, prevention of complications and subsequent prognosis. Open questions relate to the source of endogenous glucose production in GSD1 patients which increases as a function of age from 50% to 100% of normal, concomitant with an improvement in the patients fasting tolerance. Several complications, the nature of which is incompletely understood, tend to occur after the first decade: Liver adenomata with a small risk of transforming into hepatoma, progressive renal disease, which may be related to the hyperlipidaemia observed in this disease, often leading to end stage renal failure, osteopenia apparently based on high bone turnover, growth retardation and delayed puberty.Conclusion: this review highlights the present knowledge of glycogen storage disease type 1 and subtypes, discussing unsolved questions, which reflect the limitation of our knowledge in the understanding of this intriguing group of diseases. Published online: 23 August 2002     

How many forms of glycogen storage disease type I?

 Glucose-6-phosphatase is a multicomponent enzymatic system of the endoplasmic reticulum, which catalyses the terminal steps of gluconeogenesis and glycogenolysis by converting glucose-6-phosphate to glucose and inorganic phosphate. Glycogen storage diseases type I (GSD I) are a group of metabolic disorders arising from a defect in a component of this enzymatic system, i.e. the glucose-6-phosphate hydrolase (GSD Ia), the glucose-6-phosphate translocase (GSD Ib) and possibly also the translocases for inorganic phosphate (GSD Ic) or glucose (GSD Id). The genes encoding the glucose-6-phosphate hydrolase and the glucose-6-phosphate translocase have both been cloned and assigned to human chromosomes 17q21 and 11q23, respectively. Investigation of patients with GSD I shows that those with GSD Ia are mutated in the glucose-6-phosphate hydrolase gene, whereas those diagnosed as GSD Ib, GSD Ic or GSD Id are mutated in the glucose-6-phosphate translocase gene, and are therefore GSD Ib patients, in agreement with the fact that they all have neutropenia or neutrophil dysfunction. This suggests that the biochemical assays used to differentiate GSD Ic and GSD Id from GSD Ib are not reliable. Conclusion In practice therefore appears to be only two types of GSD I (Ia and Ib), which can be differentiated by (1) measurement of glucose-6-phosphatase activity in fresh and detergent-treated homogenates and (2) by mutation search in the genes encoding the glucose-6-phosphate hydrolase and the glucose-6-phosphate translocase. Received: 20 July 1999 and in revised form: 1 October 1999 / Accepted: 1 October 1999     

Improved neutrophil function in a glycogen storage disease type 1b patient after liver transplantation

Patients with glycogen storage disease type 1b (GSD1b) not only show hepatomegaly, hypoglycaemia and lactic acidosis, but also neutropenia and neutrophil dysfunction. Here, we report improvement of neutropenia and neutrophil function in a 22-year-old male GSD1b patient who had undergone living-related partial liver transplantation (LT) at 18 years of age. After LT, the patients infectious episodes decreased, gastrointestinal symptoms ameliorated, neutrophil counts increased, and neutrophil function tests normalised. Conclusion:although it is not known whether this improvement was causally related to liver transplantation, this may be the first recorded case of restoration of neutrophil dysfunction in a glycogen storage disease type 1b patient.Abbreviations G6PT glucose-6-phosphate translocase - GSD glycogen storage disease - GSD1b glycogen storage disease type 1b - LT liver transplantation - PMA phorbol-12-myristate-13-acetate - rhGCSF recombinant human granulocyte colony stimulating factor     

Genotype/phenotype correlation in glycogen storage disease type 1b: a multicentre study and review of the literature

We studied the genotype/phenotype correlation in a cohort of glycogen storage disease type (GSD) 1b patients. A total of 25 GSD1b patients, 13 females and 12 males, age range: 4.3–28.4 years, mean:14.6±6.8 years; median: 15 years, representing the entire case load of Italian GSD1b patients, were enrolled in the study. Molecular analysis of the glucose 6-phosphate translocase (G6PT1) gene was performed in all patients. We analysed the presence of a correlation among both the clinical features associated with GSD1b (neutropenia, frequency of admission to the hospital for severe infections) and the presence of systemic complications (liver adenomas, nephropathy, bone mineral density defect, polycystic ovaries, short stature, inflammatory bowel disease) and the mutations detected in each patient. Nine patients were homozygous or compound heterozygous for mutations causing stop codons. In particular, three patients were homozygous for the same mutation (400X); of these patients, one showed chronic neutropenia with severe and frequent infections and severe inflammatory bowel disease, another patient cyclic neutropenia associated with rare bacterial infections and mild bowel involvement and the last one normal neutrophil count. Two patients were homozygous for the mutation 128X; one of these patients did not show neutropenia, whereas the other one had severe neutropenia needing frequent hospital admission and was under granulocyte-colony stimulating factor treatment. In three patients no mutations were detected. Conclusion:no correlation was found between individual mutations and the presence of neutropenia, bacterial infections and systemic complications. These results suggest that different genes and proteins modulate neutrophil differentiation, maturation and apoptosis and thus the severity and frequency of infections. The absence of detectable mutations in three patients could suggest that a second protein plays a role in microsomal phosphate transport.     

Impaired monocyte function in glycogen storage disease type Ib

Phagocyte (neutrophil and monocyte) function was evaluated in a boy with glycogen storage disease type Ib. Neutrophils were found to be defective in motility and respiratory burst and monocytes showed a defect in respiratory burst but not in motility. These results suggested that the glucose-6-phosphate transport system plays a role in the function of neutrophils and monocytes and that these two phagocytes are different from each other in their energy metabolism for motility.Abbreviations GSD Ia Glycogen storage disease type Ia - GSD Ib glycogen storage disease type Ib - G6P glucose-6-phosphate - G6Pase glucose-6-phosphatase - PHA phytohemagglutinin - CL chemiluminescence - ZAS zymosan-activated serum - FMLP N-formylmethionyl-leucyl-phenylalanine - CSA colony-stimulating activity     

Hypercalcemia in glycogen storage disease type I patients of Turkish origin

Glycogen storage disease type I (GSD I) is an autosomal recessive disorder caused by defects in the glucose-6-phosphatase complex. Deficient activity in the glucose-6-phosphatase-a (G6Pase) catalytic unit characterizes GSD IA and defects in the glucose-6-phosphate transporter protein (G6PC) characterize GSD IB. The main clinical characteristics involve fasting hypoglycemia, hyperuricemia, hyperlactatemia, and hyperlipidemia. Hypercalcemia arose as an unknown problem in GSD I patients, especially in those with insufficient metabolic control. The aim of the present study was to obtain the prevalence of hypercalcemia and to draw attention to the metabolic complications of GSD I patients, including hypercalcemia in poor metabolic control. Hypercalcemia frequency and the affecting factors were studied cross-sectionally in 23 GSD I pediatric subjects. Clinical diagnosis of GSD I was confirmed in all patients either through documentation of deficient G6Pase enzyme activity levels on liver biopsy samples or through G6PC gene sequencing of DNA. Hypercalcemia was detected in 78.3% of patients with GSD I. Different from the previous report about hypercalcemia in a GSD IA patient who had R83H and 341delG mutations, we could not identify any genotype-phenotype correlation in our GSD I patients. Hyperlactatemia and hypertriglyceridemia correlated significantly with hypercalcemia. Furthermore, no differences in serum calcium concentrations could be demonstrated between patients with optimal metabolic control. We observed hypercalcemia in our series of GSD I patients during acute metabolic decompensation. Therefore, we speculate that hypercalcemia should be considered as one of the problems of GSD I patients during acute attacks. It may be related with prolonged lactic acidosis or may be a pseudohypercalcemia due to hyperlipidemia that can be seen in GSD I patients with poor metabolic control.     

Glycemic management in living donor liver transplantation for patients with glycogen storage disease type 1b

GSD type 1b is an autosomal recessive inborn error of carbohydrate metabolism caused by defects of the G6Pase translocase (G6PT). Patients with GSD1b have severe hypoglycemia with several clinical manifestations of hepatomegaly, obesity, a doll-like face, and neutropenia. LT has been indicated for severe glucose intolerance. This study retrospectively reviewed glycemic management of eight children with a diagnosis of GSD1b who underwent liver transplantation (LDLT). Between November 2005 and September 2011, 172 children underwent LDLT, of which eight (4.7%) were indicated for GSD1b. Glucose-rich solution was placed in all children when preoperative fasting started to prevent preoperative hypoglycemia. During the reperfusion of graft, the glucose administration could significantly be reduced to maintain the proper blood glucose level, while the dosage of glucose administration prior to reperfusion of graft was significantly higher in the patients with GSD1b in comparison with patients with BA. The current series also showed significantly high incidence of infectious complications in the patients with GSD1b owing to persistent neutropenia after LDLT. All patients are doing well with an excellent quality of life owing to the stabilization of glucose intolerance. This current study clearly documented drastic change in glycemic management in LDLT. Cautious perioperative management to prevent hypoglycemia and infection is crucial for successful LT.     

Acute myelogenous leukemia and glycogen storage disease 1b

Glycogen storage disease 1b (GSD 1b) is caused by a deficiency of glucose-6-phosphate translocase and the intracellular accumulation of glycogen. The disease presents with failure to thrive, hepatomegaly, hypoglycemia, lactic acidosis, as well as neutropenia causing increased susceptibility to pyogenic infections. We present a case of a young woman with GSD 1b who developed acute myelogenous leukemia while on long-term granulocyte colony-stimulating factor therapy. The presence of two rare diseases in a single patient raises suspicion that GSD 1b and acute myelogenous leukemia are linked. Surveillance for acute myelogenous leukemia should become part of the long-term follow-up for GSD 1b.     

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

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. Received: 6 September 1999 and in revised form: 29 October 1999 / Accepted: 29 October 1999     

糖原累积症Ⅰb型15家系SLC37A4基因分析研究

目的 研究中国人糖原累积症Ⅰb型SLC37A4基因突变状况.方法 对临床表现为肝大、空腹低血糖、高乳酸血症、高脂血症和粒细胞减少的15家系17例患者进行外周血DNA直接测序,分析SLC37A4基因突变情况.用限制性内切酶片段长度多态性方法对于新发现的错义突变给予分析判断.用RT-PCR方法对于新发现的剪切突变进行分析.并对患者的临床表现和基因型进行比较分析.结果 在15家系的17例患者的28个等位基因上共检测出11种突变和12种基因型,包括错义突变6个,p. Leu23Arg、p.Gly115Arg、p.Gly149Glu、p.Pro191Leu、p.Gly281Val和p.Arg415Gly;剪切突变2个,c,784+1G＞A和c.870+5G＞A;无义突变1个,p.Arg415X;缺失突变2个,c.1014_1120del107和c.1042_1043 del CT.突变p.Pro191Leu、p.Gly149Glu和c.870+5G＞A为最常见突变,分别占37%,15%和11%.结论 从17例糖原累积症Ⅰb型中国患者中共检出突变11种,包括7种新突变,最常见突变为p.Pro191leu、p.Gly149Glu和c.870+5G＞A.

Abstract：

Objective Glycogen storage disease type Ⅰ b (GSD Ⅰ b, MIM: 232220 ) is an autosomal recessive inborn error of metabolism caused by deficiency of the glucose-6-phosphate translocase.The clinical manifestations include symptoms and signs of both the typical GSD Ⅰ a, including hepatomegaly,fasting hypoglycemia, lactic acidemia and hyperlipedemia, and the dysfunction of neutrophils of recurrent infection and neutropenia. More than 84 mutations have been identified since the discovery of the SLC37A4 gene as the disease causing gene. Up to date, 5 mutations in 4 Chinese patients were reported from Hong Kang and Taiwan. In order to see the spectrum of the SLC37A4 gene mutations and the correlation between genotype and phenotype in patients with GSD Ⅰ b of the mainland of China, the authors investigated 17 GSD Ⅰ b patients from 15 families in this study. Method Data of 17 patients from 12 provinces, 11 male and 6 female, aged 6 months to 35 years, were collected from the genetic clinics of Peking Union Medical College Hospital from Oct. 2006 to Mar. 2009. All of them were Han Chinese in ethnicity. Consanguineous status was confirmed in 2 unrelated patients. All patients were presented with hepatomegaly, fasting hypoglycemia,lactic acidemia, hyperlipedemia and neutropenia with variable frequency of infections. The full coding exons, their relevant exon-intron boundaries, and the 5'- and 3'-flanking regions of the SLC37A4 gene were amplified and directly sequenced. RT-PCR was performed to verify the effect of the 2 novel splicing mutations. Result A total of 11 mutations were identified in 15 families. Four mutations, p. Gly149Glu,p. Pro191Leu,p. Arg415X and c. 1042_1043 del CT, were previously reported, and seven mutations, p.Leu23Arg, p. Gly115Arg, p. Gly281Val, p. Arg415Gly, c. 784 + 1G ＞ A, c. 870 + 5G ＞ A and c. 1014_1120del107, were novel. The frequent mutations are p. Pro191Leu, p. Gly149Glu and c. 870 + 5G ＞ A,accounting for 37%, 15% and 11% of mutant alleles respectively. RT-PCR analysis of novel mutation c. 784 + 1G ＞ A confirmed the splicing of exon 5 of 159 bp, causing inframe deletion. While mutation c. 870 +5G ＞ A was proved to cause exon 6, 86 bp, deletion causing frame-shift. Among 15 families, 12 genotypes were identified, including 3 with homozygous mutation and 9 with compound heterozygous mutations.Homozygous p. Pro191 Leu mutation was the only genotype detected in more than 1 family and was found in 4 unrelated families, including 1 patient from consanguineous marriage. Conclusion A total of 11 SLC37A4 gene mutations were identified in 15 families of the mainland of China. The frequent mutations are p. Pro191Leu,p. Gly149Glu and c. 870 + 5G ＞ A. The number of Chinese SLC37A4 gene mutations was extended from 5 to 14.     

Glycogenoses type 1b and 1c

In type 1 glycogen storage diseases, glucose-6-phosphatase may be present but associated with impaired transport of glucose-6-phosphate (type 1b) or inorganic phosphate (type 1c) through microsomal membranes. The type 1c is very rare (2 published cases). The more frequent type 1b presents all the clinical manifestations of type 1a and specific signs: recurrent stomatitis, frequent infections, chronic inflammatory bowel disease secondary to neutropenia and neutrophil dysfunction. Glucose-6-phosphatase activity is low when measured on fresh liver tissue, but is restored after detergent treatment. A good metabolic control does not influence neutropenia and its consequences.     

Vitamin E supplementation improves neutropenia and reduces the frequency of infections in patients with glycogen storage disease type 1b

Background  Neutropenia and/or neutrophil dysfunction are part of glycogen storage disease type 1b (GSD1b) phenotype. Recent studies indicated that activation of apoptosis and increased reactive oxygen species are implicated in the pathogenesis of neutropenia in GSD1b. Methods  We studied seven GSD1b patients over a 2-year-period to evaluate the efficacy of vitamin E, a known antioxidant, in preventing or improving the clinical manifestations associated with neutropenia and neutrophil dysfunction. Frequency and severity of infections, neutrophil counts and function, ileocolonoscopy and intestinal histology, were monitored. During the first year, patients did not assume vitamin E; during the second year of the study, vitamin E supplementation was added to their therapeutic regimens. Results  During vitamin E supplementation, the mean values of neutrophil counts were significantly higher (p < 0.05) and neutrophil counts lower than 500/mm³ were found less frequently (p < 0.05); the frequency and severity of infections, mouth ulcers and perianal lesions, was reduced (p < 0.05); ileocolonoscopy and histology showed a mild improvement. Vitamin E supplementation did not result in changes in neutrophil function. Conclusions  These results suggest that vitamin E supplementation might be beneficial in GSD1b patients and may alleviate disease manifestations associated with neutropenia.     

糖原累积症Ⅰa型-纯合G727T突变患儿的表型分析

目的　对临床诊断为糖原累积症Ⅰa型的患儿及其父母进行葡萄糖 6 磷酸酶 (G6Pase)的基因突变筛查 ,并对基因突变完全相同的患儿进行临床特点的比较分析。方法　提取患儿及其父母外周血DNA ,分别进行G6Pase基因五个外显子的PCR扩增 ,纯化后进行DNA直接测序 ;对基因突变相同的 6家系 7例患儿进行临床表现、生化改变及对治疗反应的比较分析。结果　所有 7例患儿均为G6Pase基因外显子 5核苷酸位点第 72 7处纯合子型G→T的单个碱基突变 (G72 7T) ,而其父母均为此杂合突变的携带者。基因突变完全相同的 7例患儿临床表现的严重性、对治疗的反应不全相同 ,除经典的低血糖、生长发育落后、肝脏肿大、肾脏肿大、代谢性酸中毒和乳酸血症外 ,尚有脾大 (1例 ) ,轻度肝功能受损 (6例 ) ,多发肝腺瘤 (1例 )等。结论　G72 7T突变很可能是中国人种糖原累积症Ⅰa型的较常见突变 ;具有相同突变的患儿不仅临床表现轻重不同 ,而且 ,对生玉米淀粉治疗的反应也各有差异 ;通过典型的临床及生化表现辅以外周血基因分析 ,完全可以取代传统的有创伤性肝穿刺酶学分析的确诊方法     

Glycogen storage disease type Ib: familial bleeding tendency

A mild bleeding tendency with characteristics of the von Willebrand disease was documented in family members of a girl with glycogen storage disease type Ib (GSD) Ib). It was assumed that a defective glucose-6-phosphate dependent microsomal glycoprotein synthesis was involved in the bleeding disorder of the patient and the GSD Ib heterozygotes.Abbreviations GSD Ia glycogen storage disease type Ia - GSD Ib glycogen storage disease type Ib - G6P glucose-6-phosphate - G6P-ase glucose-6-phosphatase     

Glycogen storage disease type 1b: microsomal glucose-6-phosphatase system in two patients with different clinical findings

The basic defect in glycogen storage disease (GSD) type 1b was investigated in two patients: one, (Y.S.), a severely affected infant and the other, (Y.M.), an adult with mild clinical symptoms. The enzymatic studies on liver needle biopsy specimens from the two patients indicated that glucose-6-phosphate (G-6-P) phosphohydrolase activity of the "intact microsomes" was partially deficient (20% of that in controls) in Y.M. and undetectable in Y.S. Activities of G-6-P phosphohydrolase in the disrupted microsomes of Y.S. and Y.M. are higher than those in the disrupted microsomes of controls (12.60 mumole/min/g liver in Y.S., 9.18 in Y.M. and 6.26 +/- 1.22, mean +/- S.D. in controls). Our study also shows that PPi phosphohydrolase activities of the "intact microsomes" from both patients (6.07 mumol/min/g liver in Y.S. and 5.36 in Y.M.) were greater than those of the controls (3.23 +/- 0.77 mumole/min/g wet weight liver). These results indicate that the G-6-P translocase was the locus of the defect in both patients with GSD type 1b. Clinical symptoms and enzymatic studies suggest that the clinical severity of this disorder depends on the level of residual activities of G-6-P translocase. Kinetic studies showed an abnormally high Km of the residual G-6-P translocase in Y.M., suggesting a structural gene mutation. The systematic assay method for glucose-6-phosphatase system, which requires only 15 mg of liver tissues, is also described.     

糖原累积病Ib型患儿基因突变分析与临床研究

目的：糖原累积病Ib型（GSDIb）是由于SLC37A4基因突变引起葡萄糖-6-磷酸转移酶（G6PT）活性缺陷所致,该病患者大部分有反复感染及炎症性肠病的发生,预后较差。SLC37A4基因的检测对GSDIb患者的诊断、分型、预测患者的预后尤为重要。本文旨在研究糖原累积病Ib型患儿SLC37A4基因突变的情况,探讨基因型与临床表型的关系。方法：应用聚合酶链反应直接测序的方法,对拟诊GSDIb型的28例患儿行SLC37A4基因外显子及其相邻区域的突变筛查。结果：7例患儿检测到SLC37A4基因突变,检出率为25% (7/28例),包括错义突变：p.Gly149Glu（9/13,69%）、p.Gly115Arg（1/13,8%）、p.Pro191Leu（1/13,8%）;移码突变：c.959-960 insT（1/13,8%）;剪接突变：c.870+5G>A（1/13,8%）。结论：c.959-960 insT为新突变,p.Gly149Glu为本研究最常见的突变,p.Gly149Glu突变可能与患儿的严重感染相关。     

Neutropenia, neutrophil dysfunction, and inflammatory bowel disease in glycogen storage disease type Ib: results of the European Study on Glycogen Storage Disease type I

OBJECTIVE: To investigate the incidence, the severity, and the course of neutropenia, neutrophil dysfunction, and inflammatory bowel disease (IBD) in glycogen storage disease (GSD) type Ib. METHOD: As part of a collaborative European Study on GSD type I, a retrospective registry was established in 12 European countries that included all patients with GSD-I who were known at the centers and were born from 1960 to 1995. Of a total of 288 patients with GSD-I, 57 who had GSD-Ib form the basis of this study. RESULTS: Neutropenia (defined as an absolute neutrophil count <1 x 10(9)/L) was found in 54 patients. In 64% of the patients neutropenia was documented before the age of 1 year, but in 18% of the patients neutropenia was first noted between the ages of 6 and 9 years. Neutropenia was persistent in 5 patients and intermittent without any clear cyclical course in 45. Neutrophil function was investigated in 18 patients with neutropenia and was abnormal in all. Perioral infections were reported in 37 patients, perianal infections in 27 patients, and protracted diarrhea in 23 patients. Findings on colonoscopy and radiologic studies in 10 of 20 patients suspected to have IBD were abnormal in all. All patients with IBD, perioral infections, and perianal infections had neutropenia. CONCLUSIONS: Intermittent severe neutropenia is frequently found in patients with GSD-Ib. The study also indicates that IBD in GSD-Ib is underdiagnosed; up to 77% of the patients studied had evidence of IBD, all of whom had neutropenia. IBD was not detected in those with normal neutrophil counts. These findings support the notion that neutropenia and/or neutrophil dysfunction in GSD-Ib and IBD are causally related.     

糖原累积病Ⅰa型1例及其家系的临床和分子遗传分析

目的：研究1例糖原累积病Ⅰa型患者及其家系的基因突变情况。方法：应用聚合酶链反应扩增葡萄糖-6-磷酸酶基因（G6PC基因）全部5个外显子,通过DNA直接测序的方法,对糖原累积病Ⅰa型患者及其家系中父、母、姐姐的G6PC基因进行突变检测。结果：在患者G6PC基因的第5外显子上的第743碱基发生杂和突变,由G转变为A,导致G6Pase蛋白第222位氨基酸由甘氨酸变为精氨酸（G222R）,家系中父亲、姐姐均未发现该突变,而母亲携带与患者相同突变。结论：首次在国内报道G6PC基因的G222R突变,丰富了糖原累积病Ⅰa型在中国人群的突变谱。