Systematic literature review of the epidemiology of glycogen storage disease type 1a

Glycogen storage disease (GSD) type 1a is an inherited autosomal recessive metabolic disease caused by a deficiency in glucose-6-phosphatase activity. The objectives of this research were to systematically review the published literature on the epidemiology of GSD 1a and to assess the performance of reported epidemiology measures in a simulation model. In this systematic literature review 2,539 record titles and abstracts were screened. Of these, only 11 studies contained relevant data on GSD 1a disease epidemiology. Reported disease frequency ranged from 0.085/100,000 to 10.3/100,000 newborns when considering all the GSD literature. When this was narrowed to GSD 1 and GSD 1a, the range was tightened to 0.25-3.02/100,000 and 0.085-4.9/100,000 newborns, respectively. Most of the identified studies counted the number of diagnoses in a defined period and related to the number of births in the same (Dx method) or different time period (DoB method). The simulation model results indicate that in most of the situations, the Dx method provides a closer estimate to the true disease incidence than the DoB method. Despite the scarcity of epidemiology data, the results of this systematic review strongly support that GSD 1a and its parent disease groups (GSD and GSD 1) are rare diseases.

Glycogen storage disease type I patients with hyperlipidemia have no signs of early vascular dysfunction and premature atherosclerosis

BACKGROUND AND AIMS

Glycogen storage disease type I (GSD I) is associated with hyperlipidemia, a known risk factor for premature atherosclerosis. Few studies have addressed endothelial dysfunction in patients with GSD I, and these studies yielded controversial results.

METHODS AND RESULTS

We investigated vascular dysfunction in a cohort of 32 patients with GSD I (26 GSD Ia, 6 GSD Ib, mean age 20.7 (4.8-47.5) years) compared to 32 age-, gender-, and BMI-matched healthy controls using non-invasive techniques such as quantification of carotid intima media thickness, retinal vessel analysis and 24 h-blood pressure measurements. In addition, early biomarkers of inflammatory and oxidative endothelial stress were assessed in blood. Although GSD I patients had a clearly proatherogenic lipid profile, increased oxidative stress, higher levels of high sensitivity C-reactive protein and increased lipoprotein associated phospholipase A2 activity, functional and structural parameters including carotid intima media thickness and retinal vessel diameters did not indicate premature atherosclerosis in this patient cohort. Blood pressure values and pulse wave velocity were comparable in patients and healthy controls, while central blood pressure and augmentation index were higher in GSD patients.

CONCLUSION

Our data suggest that GSD I is not associated with early vascular dysfunction up to the age of at least 20 years. Further studies are needed to elucidate the possibly protective mechanisms that prevent early atherosclerosis is GSD I. Longer follow-up studies are required to assess the long-term risk of vascular disease with increased oxidative stress being present in GSD I 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.

Red blood cell disorders in Rwandese neonates: screening for sickle cell disease and glucose-6-phosphate dehydrogenase deficiency

Objectives: To determine the prevalence of haemoglobin (Hb) variants and glucose-6-phosphate dehydrogenase (G6PD) deficiency in Rwanda.

Methods: During a two-month period in 2005, 987 cord blood samples were obtained in two hospitals in Kigali and Butare, Rwanda. Screening for sickle cell disorders, other Hb disorders, G6PD deficiency and other rare erythroenzymopathy deficiencies was done using isoelectric focusing techniques and quantitative kinetic assays, respectively.

Results: The prevalence of Hb S trait was 2.7% and that of G6PD deficiency was 3.8%. No neonate suffered from a sickle cell disease (homozygous for Hb S or compound heterozygous for Hb S), from another clinically significant haemoglobinopathy, or from pyruvate kinase or glucose phosphate isomerase deficiency.

Conclusions: Sickle cell disorders should be considered a public health problem in Kigali and Butare. A systematic neonatal screening programme for those disorders, and to diagnose G6PD deficiency, seems reasonable, but local health priorities must be considered. Adapted management of hereditary sickle cell and G6PD disorders should be available.

Thalassaemia and glucose-6-phosphate dehydrogenase deficiency in sickle-cell disorder patients in Taiz, Yemen

A pilot study was conducted to determine the prevalence and haematological characteristics of the interaction between thalassaemia or/and glucose-6-phosphate dehydrogenase (G6PD) deficiency in patients with sickle-cell disorder (SCD) in Taiz city, Yemen, where the prevalence of sickle-cell trait (HbAS) is 8.2%. Blood samples were collected from 31 SCD patients. Complete blood count and haemoglobin electrophoresis, G6PD activity and serum ferritin were determined. Thalassaemia was found in 6 patients (19.4%) and G6PD deficiency (6 mild and 1 severe) was detected in 7 patients (22.6%). The frequency ofthalassaemia and/or G6PD deficiency with SCD was high and this may have an effect on the severity of the clinical course of SCD in Taiz. The study should be repeated with DNA analysis to define the nature of the globin gene defect and to clarify its role in the severity of SCD

[Post-transfusion hemolytic reactions in regions endemic for the hereditary glucose-6-phosphate dehydrogenase deficiency]

This paper deals with the problem of hemocomponent therapy in the use of blood components from donors with hereditary glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and with the matters of family donation in this blood anomaly. Posttransfusion hemolytic reactions during transfusions of packed red blood cells from donors with hereditary blood anomaly are retrospectively analyzed. Recommendations are formulated for recipients who have undergone transfusions of blood components from donors with G-6-PD deficiency.

Vascular dysfunction in glycogen storage disease type I

OBJECTIVE

To determine cardiovascular disease risk in a larger cohort of patients with glycogen storage disease (GSD) I through the use of noninvasive measures of arterial function and anatomy.

STUDY DESIGN

Carotid intima media thickness (IMT), radial artery tonometry, and brachial artery reactivity were performed in 28 patients with GSD I (13F/15M, mean age 23 years) and 23 control subjects (19F/4M, mean age 23 years).

RESULTS

The primary outcome measure, mean left distal IMT was greater in the GSD cohort (0.500+/-0.055 mm) than in the control group (0.457+/-0.039 mm) (P= .002, adjusted for age, sex, and body mass index). Mean augmentation index measured by radial artery tonometry was higher in the GSD cohort (16.4%+/-14.0%) than in the control group (2.4%+/-8.7%) (P< .001). No significant difference was observed between mean brachial artery reactivity in the GSD cohort (6.3%+/-4.9% change) versus control subjects (6.6%+/-5.1% change) (P= .46).

CONCLUSIONS

GSD I is associated with arterial dysfunction evident by increased IMT and augmentation index. Patients with GSD I may be at increased risk for cardiovascular disease.

Glycogen storage disease type I in Tunisia: an epidemiological analysis

OBJECTIVE

Analysis of epidemiological data concerning GSD I in Tunisia.

SUBJECTS AND METHODS

All the cases diagnosed as GSD I between 1992 and 2005 in a paediatric department recruiting all the metabolic diseases referred from the North of Tunisia were reviewed. Individual data (sex, socioeconomic and educational background, geographic origins, insurance coverage) were collected and pedigrees were reconstituted.

RESULTS

Twenty-two cases (9 boys and 13 girls from 20 homes) were identified. Fourteen belonged to 11 families originating from the North of Tunisia; ten of them are still alive. Both parents in 4 homes (21%) and one parent in 9 homes (47%) were illiterate. Most of the homes (60%) had a low income and 45% comprised at least 3 children. Only 7 homes (35%) had health insurance. Pedigrees indicated 44 infant deaths and at least 10 other cases fulfilling the clinical features of GSD I but not diagnosed.

CONCLUSION

The paediatric prevalence of GSD I in the North of Tunisia can be estimated to 7.93 cases per one million inhabitants and its incidence to 1/100,000 births. However, it is likely to be more frequent because of underreporting or underdiagnosis leading to precocious deaths.

A comprehensive study on the major mutations in glucose-6-phosphate dehydrogenase-deficient polymorphic variants identified in the coastal provinces of Caspian Sea in the north of Iran

BACKGROUND

The aim of this study was the molecular analysis of G6PD patients for G6PD mutations in the coastal provinces of the Caspian Sea in north of Iran.

METHODS

Studies on G6PD deficiency in the coastal provinces of the Caspian Sea in Iran were performed in 248 patients with a history of favism, in Mazandaran, Golestan and Gillan provinces, which contributed 74, 71 and 103 samples, respectively. Three different major polymorphic variants were determined by molecular analysis, using SSCP, sequencing and PCR-RFLP methods. Firstly, all Mazandaranian samples were searched for the Mediterranean mutation by PCR-RFLP method. The remaining samples of the Mazandaran province were analysed by SSCP followed by sequencing for other mutations. Then, our research was expanded in two other provinces, Golestan and Gillan, by the PCR-RFLP method.

RESULTS

Three different major polymorphic variants were found: G6PD Mediterranean 75.4% (187 out of 248), G6PD Chatham 19.76% (49 out of 248), G6PD Cosenza 2.02% (5 out of 248) and 7 samples out of 248 remained unknown. Also, there was no significant difference in the incidence of various G6PD polymorphic variants with mean age, and various blood work values such as Hb, WBC and MCV between two major variants (p>0.20).

CONCLUSIONS

These results which are the first molecular investigation in north of Iran indicate a higher prevalence of G6PD Chatham in this large Iranian population than anywhere else in the world. The distribution of these G6PD variants is more similar to that found in an Italian population (80-84% for Mediterranean, 20% for Chatham and 1.9% for Cosenza mutation). Although the origin of Iranian population is rather uncertain, the closer similarity of the mutation spectrum to Italian rather than Middle Eastern population may indicate that these populations have a common ancestral origin.

Increased prevalence of thyroid autoimmunity and hypothyroidism in patients with glycogen storage disease type I

OBJECTIVE

To investigate the hypothalamus-pituitary-thyroid axis in patients with glycogen storage disease type 1(GSD1).

STUDY DESIGN

Ten patients with GSD1a, 7 patients with GSD1b, and 34 sex- and age-matched healthy control subjects were enrolled in the study.

RESULTS

The levels of serum-free thyroxine (FT4) were significantly lower in patients with GSD1a and GSD1b (P < .05), whereas thyrotropin was significantly higher compared with control subjects only in patients with GSD1b (P < .005). Thyroglobulin and thyroperoxidase auto-antibodies were significantly higher in patients with GSD1b than in patients with GSD1a and control subjects (P < .005). After thyrotropin-releasing hormone stimulation, an enhanced thyrotropin response was found in patients with GSD1a and patients with GSD1b (P < .005) compared with control subjects. The presence of a subclinical or overt hypothyroidism was found in 4 of 7 patients with GSD1b and in no patient with GSD1a (chi2 = 7.47, P < .005) or control subject (chi2 = 27.2, P < .0001).

CONCLUSIONS

Patients with GSD1b have an increased prevalence of thyroid autoimmunity and hypothyroidism, although patients with GSD1a have little evidence of thyroid abnormalities. Concomitant damage at the level of the hypothalamus or pituitary gland might be hypothesized on the basis of the slightly elevated thyrotropin levels, even in patients with overt hypothyroidism.

Frequency of malaria and glucose-6-phosphate dehydrogenase deficiency in Tajikistan

Background

During the Soviet era, malaria was close to eradication in Tajikistan. Since the early 1990s, the disease has been on the rise and has become endemic in large areas of southern and western Tajikistan. The standard national treatment for Plasmodium vivax is based on primaquine. This entails the risk of severe haemolysis for patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Seasonal and geographical distribution patterns as well as G6PD deficiency frequency were analysed with a view to improve understanding of the current malaria situation in Tajikistan.

Methods

Spatial and seasonal distribution was analysed, applying a risk model that included key environmental factors such as temperature and the availability of mosquito breeding sites. The frequency of G6PD deficiency was studied at the health service level, including a cross-sectional sample of 382 adult men.

Results

Analysis revealed high rates of malaria transmission in most districts of the southern province of Khatlon, as well as in some zones in the northern province of Sughd. Three categories of risk areas were identified: (i) zones at relatively high malaria risk with high current incidence rates, where malaria control and prevention measures should be taken at all stages of the transmission cycle; (ii) zones at relatively high malaria risk with low current incidence rates, where malaria prevention measures are recommended; and (iii) zones at intermediate or low malaria risk with low current incidence rates where no particular measures appear necessary. The average prevalence of G6PD deficiency was 2.1% with apparent differences between ethnic groups and geographical regions.

Conclusion

The study clearly indicates that malaria is a serious health issue in specific regions of Tajikistan. Transmission is mainly determined by temperature. Consequently, locations at lower altitude are more malaria-prone. G6PD deficiency frequency is too moderate to require fundamental changes in standard national treatment of cases of P. vivax.

Genetic Blood Disorders Survey in the Sultanate of Oman

The Genetic Blood Disorders Survey is the first community-based survey in the Arabic world and the Middle East to determine the prevalence of the most common genetic blood disorders. The objective of the survey was to determine the prevalence of the most common genetic blood disorders reported among Omani children under 5 years of age in order to provide the planners and policy-makers with reliable information suitable for formulating health policies, planning, and evaluation. The survey was designed, executed, and financed by the Ministry of Health of the Sultanate of Oman. To reduce costs and save effort and time, data collection for the survey was implemented with the Gulf Family Health Survey (GFHS). The GFHS in the Sultanate of Oman is a research project undertaken by the Council of Health Ministers of the Gulf Co-operation Council States. The six member countries have participated in this GFHS project. A total of 6103 households were interviewed. From these households 6342 children under 5 years of age were taken by their parents to neighbourhood hospitals or health centres for blood collection. Fifty-one per cent of the sample were male and 49 per cent were female. Among the child respondents, 17.9 per cent were in the age group 0 to < 1 year, 20.3 per cent were in the age group 1 to < 2 years, 21.1 per cent were in the age group 2 to < 3 years, 20.5 per cent were in the age group 3 to < 4 years, and 20.2 per cent were in the age group 4 to 5 years. Fifty-five per cent of the mothers of the children studied were illiterate, 9 per cent could read and write but had less than primary education, 20 per cent had completed primary school, 9 per cent had attended preparatory school, 5 per cent had attended secondary school, 1 per cent had had intermediate education, while 0.6 per cent had completed university or higher education. The results of this survey revealed that haemoglobinopathies are prevalent in Oman; the prevalence of sickle cell trait was 6 per cent, and of beta-thalassaemia 2 per cent. The prevalence of sickle cell and homozygous beta-thalassaemia were 0.2 and 0.07 per cent, respectively. Other abnormal haemoglobins (Hb) have been detected in this survey; HbD (0.6 per cent), HbE (0.3 per cent), HbC (0.02 per cent). Combination of sickle cell with other abnormal Hb was also detected at low prevalence. Glucose-6-phosphate dehydrogenase (G6PD) enzyme deficiency had a high prevalence in Oman, being 25 per cent in males and 10 per cent in females. Among the children studied, three-quarters (74.5 per cent) were found to be free from haemoglobinopathies and G6PD normal, the rest (25.5 per cent), either had haemoglobinopathies (7.5 per cent), G6PD deficiency (16 per cent) or a combination of G6PD deficiency with at least one abnormal Hb (2 per cent). The prevalence of total haemoglobinopathies in Oman was 9.5 per cent. The prevalence of sickle cell trait varied between regions, North Sharqiya had the highest prevalence of 10 per cent. Dakhiliya (9 per cent), followed by Muscat and South Batinah 8 and 7.9 per cent, respectively. The prevalence of sickle cell trait declined by a half in Musandam, South Sharqiya, Dhahira, and North Batinah (4.7, 3.9, 3.9, and 2.9 per cent respectively). Dhofar had the lowest prevalence of 0.2 per cent and no cases of sickle cell trait were found in the Al-Wousta region in the sample selected. The prevalence of beta-thalassaemia trait ranged from 3.9 to 0.2 per cent. Three regions had high rates: North Batinah (3.9 per cent), Muscat (2.8 per cent), and Dakhiliya (2 per cent). The other five regions in the Sultanate have lower rates: Dhahira (1.7 per cent), Musandam (1.6 per cent), South Batinah (1.5 per cent), South Sharqiya (1.2 per cent), and North Sharqiya (1.1 per cent). The prevalence of beta-thalassaemia trait in Dhofar was 0.2 per cent and no cases were detected in the Al-Wousta region. The prevalence of G6PD deficiency reached 29 per cent in Dakhiliya, 26 per cent in South Batinah, 21 per cent in Dhahira, 19 per cent in Muscat and 17 per cent in North Sharqiya and North Batinah. The prevalence declined to 10 per cent in Musandam, 9 per cent in South Sharqiya, Dhofar had the lowest prevalence of 2 per cent and no cases of G6PD deficiency were found in Al-Wousta. The male to female ratio was 2.5:1. In all regions of the Sultanate, prevalence of G6PD deficiency in males were more than twice those in females. From the above rates, it could be calculated that in the whole Sultanate 44,733 children under 5 years of age have G6PD deficiency, 14,306 have sickle cell trait, 474 have sickle cell disease, 5393 have beta-thalassaemia trait, and 175 have beta-thalassaemia major. The study showed that the mean Hb level of children under 5 years of age was 10.9 g/dl for both males and females; the mean Hb level for males was 10.89 g/dl and for females 10.99 g/dl, the difference between males and females was significant. The study revealed that half of the children under 5 years of age were anaemic. Mild anaemia was predominant (46 per cent), while moderate and severe anaemia were 4 and 0.2 per cent respectively. The status of anaemia among children improved with age; mild anaemia was prevalent in 65 per cent of children between ages 0 to < or = 1 years then decreased with age until it reached 30 per cent at 4-5 years of age. The survey produced the first normal haematological indices for children under 5 years of age to be used as a reference in the country. The blood picture of the normal subjects in the survey showed that the mean Hb value for males was 11.9 g/dl and for females 11.8 g/dl. The children had reduced values of MCH and MCV compared to normal international values, the reason for this could be alpha-thalassaemia or iron deficiency. The children maintained high values of HbF (more than 1.2 per cent) even after their first birthday. HbF reached its normal level at 5 years of age. Marriage of first cousins among the parents of the children studied under 5 years of age was 34 per cent. Total consanguinity rate including second cousin relationships and beyond was 58 per cent. We recommend that a national prevention programme for genetic blood disorders be formulated by the authorities. The programme could be included in the Ministry of Health 5-year health development programme for prevention of non-communicable diseases which already exists.

Association of glycogen storage disease 1b and Crohn disease: results of a North American survey

Glycogen storage disease (GSD)-1b has been associated with neutropenia and abnormalities of neutrophil function. Many individuals with GSD-1b manifest chronic gastrointestinal inflammation. Our study was performed to precisely establish the type, frequency, and spectrum of gastrointestinal disease in patients with GSD-lb. We established a medical database of 36 individuals affected with GSD-1b, utilizing patients at our center, disease registries, and direct contacts with North American referral centers specializing in genetic disorders. Records were reviewed, focusing on documentation of gastrointestinal involvement. Gastrointestinal symptoms or manifestations were present in approximately 75% of the patients, including chronic abdominal pain and diarrhea, perianal fistula or abscess, and oral aphthous ulceration. Of patients identified, 28% had documented inflammatory bowel disease (IBD) and an additional 22% of patients had symptoms highly suggestive of IBD, but had not undergone comprehensive diagnostic evaluation. Gastrointestinal involvement was found to be indistinguishable from idiopathic Crohn disease (CD) by detailed review of clinical, radiologic, endoscopic and histopathologic findings. Many patients had significant improvement or resolution of gastrointestinal disease in response to G-CSF treatment. The expression of CD in patients with GSD-1b may be delayed or prevented by G-CSF treatment.

CONCLUSION

a strong association exists between glycogen storage disease type 1b and inflammatory bowel disease. A high index of suspicion for Crohn disease should be applied in evaluating patients with glycogen storage disease type 1b and intestinal symptoms. These results provide further support for the hypothesis that some forms of inflammatory bowel disease may result from impaired mucosal innate immunity. Additional investigations into the intestinal disease in glycogen storage disease type 1b may be directly relevant to the etiology and treatment of idiopathic Crohn disease.

Kernicterus: an international perspective

Kernicterus occurs in all parts of the world. The risk is increased in countries where glucose-6-phosphate dehydrogenase-deficiency is common. In the 1990's more case reports of infants who developed kernicterus were published than in the previous decades. A combination of reduced concern for jaundice in newborns, early discharge with inadequate follow-up and a decreased awareness of the signs that may herald serious toxicity may have contributed to the apparent increase in the incidence of kernicterus. Although most jaundiced newborns do not need aggressive evaluation or treatment, physicians who deal with such infants still need to be vigilant. We lack the necessary tools to distinguish infants who may be particularly vulnerable to the effects of bilirubin on the brain from those who may tolerate high serum bilirubin levels without harm. Therefore it is imperative that each infant with significant jaundice be conscientiously evaluated and a plan for testing and, if necessary, therapy be formulated. Transcutaneous measurement of bilirubin is a simple tool that significantly reduces the need for invasive tests. Signs of possible neurotoxicity must never be disregarded or neglected. Any jaundiced infant who shows signs of possible neurotoxicity should receive intensive phototherapy as an emergency procedure while further evaluation continues. Further studies regarding bilirubin toxicity and neonatal jaundice are needed, both in the basic science as well as in the clinical arena.

The molecular basis of type 1 glycogen storage diseases

Glycogen storage disease type 1 (GSD-1), also known as von Gierke disease, is a group of autosomal recessive metabolic disorders caused by deficiencies in the activity of the glucose-6-phosphatase (G6Pase) system that consists of at least two membrane proteins, glucose-6-phosphate transporter (G6PT) and G6Pase. G6PT translocates glucose-6-phosphate (G6P) from cytoplasm to the lumen of the endoplasmic reticulum (ER) and G6Pase catalyzes the hydrolysis of G6P to produce glucose and phosphate. Therefore, G6PT and G6Pase work in concert to maintain glucose homeostasis. Deficiencies in G6Pase and G6PT cause GSD-1a and GSD-1b, respectively. Both manifest functional G6Pase deficiency characterized by growth retardation, hypoglycemia, hepatomegaly, kidney enlargement, hyperlipidemia, hyperuricemia, and lactic acidemia. GSD-1b patients also suffer from chronic neutropenia and functional deficiencies of neutrophils and monocytes, resulting in recurrent bacterial infections as well as ulceration of the oral and intestinal mucosa. The G6Pase gene maps to chromosome 17q21 and encodes a 36-kDa glycoprotein that is anchored to the ER by 9 transmembrane helices with its active site facing the lumen. Animal models of GSD-1a have been developed and are being exploited to delineate the disease more precisely and to develop new therapies. The G6PT gene maps to chromosome 11q23 and encodes a 37-kDa protein that is anchored to the ER by 10 transmembrane helices. A functional assay for the recombinant G6PT protein has been established, which showed that G6PT functions as a G6P transporter in the absence of G6Pase. However, microsomal G6P uptake activity was markedly enhanced in the simultaneous presence of G6PT and G6Pase. The cloning of the G6PT gene now permits animal models of GSD-1b to be generated. These recent developments are increasing our understanding of the GSD-l disorders and the G6Pase system, knowledge that will facilitate the development of novel therapeutic approaches for these disorders.

Genetic heterogeneity of glycogen storage disease type Ia in France: a study of 48 patients

Forty-eight patients with glycogen storage disease type Ia (GSD Ia) were studied. Using a combination of single-strand conformation polymorphism (SSCP) analysis, restriction enzyme digestion and direct sequencing, we were able to identify 93/96 mutant alleles, comprising 23 different mutations in the glucose-6-phosphatase gene (G6PC). Among these, 7 are novel mutations of G6PC: M5R, T111I, A241T, C270R, F322L, and two deletions, 793delG and 872delC, resulting in the same mutation at the amino acid level, fs300Ter (300X).

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.

Molecular analysis in glycogen storage disease 1 non-A: DHPLC detection of the highly prevalent exon 8 mutations of the G6PT1 gene in German patients

We investigated the molecular basis of glycogen storage disease type 1 non-A (GSD1 non-A) in 21patients. In addition to 8 novel mutations within the G6PT1 gene (c.250T>A, c.580G>A, c.627C>T, c.653-4delAG, c. 844C>A, c.1071A>C, c.1268G>A, c.1348G>A), we found a remarkably high prevalence of exon 8 mutations in German patients. The c.1211-2delCT mutation and the c.1184G>T mutation accounted for 32% and 29% of mutant chromosomes, respectively, supporting the hypothesis of a Middle European origin of these two mutations. Together with less common mutations, 79% of German GSD1 non-A patients were either homozygous or heterozygous for an exon 8 mutation. In addition to direct sequencing, these exon8 mutations could be detected by mutation-specific methods such as the detection of heteroduplex formation on polyacrylamide gel electrophoresis or by the amplification of DNA segments by allele-specific oligonucleotides. Furthermore, the use of denaturating high performance liquid chromatography (DHPLC) allowed a 100% detection and discrimination of all exon 8 mutations. In conclusion from these results, we recommend the use of either conventional or DHPLC screening as the initial non-invasive and efficient diagnostic procedure in patients with GSD1 non-A from populations with a similar distribution of mutations. Hum Mutat 16:177, 2000.

Glycogen storage disease type Ia: frequency and clinical course in Turkish children

The aim of this study was to determine the relative frequency of type Ia in glycogen storage disease (GSD) with prominent liver involvement and to determine its clinical and laboratory findings and prognosis in Turkish children. From 1980 to 1998, 45 out of 100 GSD patients (27 male) with liver involvement had been diagnosed for type Ia. The files were retrospectively evaluated and clinical and laboratory features were documented. In addition to routine laboratory evaluations, urine albumin, calcium excretions, and plasma biotinidase activity were measured. Breast-feeding was continued in all infants. After 6 months of age, uncooked cornstarch was administered to the patients. The relative frequency of type Ia in GSD with liver involvement was 45%. The diagnosis was made in 71% of patients before 2 years of age (median 1 year). Main complaint was abdominal protruding (57.8%), and main physical finding was hepatomegaly (100%). Forty percent of the patients had growth retardation at diagnosis. Among laboratory parameters, hypertriglyceridemia (97.8%) and hypertransaminasemia (95.6%) were the most frequent findings following plasma biotinidase activity, which was elevated in all patients. Microalbuminuria was determined in 52.8% of the patients and hypercalciuria in 23.8%. Histopathological findings of the liver included fibrosis (75.6%), steatosis (37.8%), mosaicism (24.4%) and nuclear hyperglycogenation (15.6%). During follow-up period, the ratio of patients with growth retardation did not change. Transaminases were decreased in 48.7% of the patients. Although triglyceride and cholesterol levels decreased in the majority of the patients, they did not normalise. The prevalence of type Ia in GSD with prominent liver involvement was found higher than the other reports. Microalbuminuria was also higher than the previous reports.

Three major G6PD-deficient polymorphic variants identified among the Mauritian population

We report the results of the first epidemiological study investigating glucose 6-phosphate dehydrogenase (G6PD) deficiency among the heterogenous Mauritian population. Mauritius has a population of approximately 1 million, and of these 66.8% are Indo-Mauritian (of Indian origin), 27.9% are Creoles (of African ancestry) and 2.1% are Sino-Mauritian, predominantly of Chinese origin. Of the 1435 Mauritian males tested, 73 (5.1%) were G6PD deficient. However, the prevalence varied considerably between the two major ethnic groups: 35/1157 (3.0%) for Indo-Mauritians and 37/267 (13.9%) for Creoles. Molecular analysis revealed three major deficient polymorphic variants; G6PD Orissa, G6PD Mediterranean and G6PD A-. G6PD Orissa (nt 131 G-->C; residue 44 Ala-->Gly) was found to be the most common variant among Indo-Mauritians: this deficient variant was recently identified to be highly characteristic of the tribal groups in central India. In Creoles the most common deficient variant was G6PD A- (27/37). These data are consistent with the different ancestral contributions to the present gene pool of the Mauritian population. This study has provided further information as to the precise nature of G6PD deficiency at the molecular level among Indians, about whom previously there was scant information. The data presented suggest that G6PD Orissa is widespread in central and southern states of India. Additionally, the identification and frequency of G6PD-deficient alleles in Mauritius is of public-health importance.

Glucose-6-phosphatase gene (727G-->T) splicing mutation is prevalent in Hong Kong Chinese patients with glycogen storage disease type 1a

Glycogen storage disease type la (GSD1a) is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase (G6Pase). We analyzed the G6Pase genes of two unrelated Chinese families with GSD1a. DNA sequencing of all five exons and the exon-intron boundaries revealed a G T transversion at nucleotide 727 (727G-->T) in exon 5, which has previously been reported to cause abnormal splicing. In one family, the subject and her affected sister were confirmed to be homozygous for this mutation and their parents to be heterozygotes. In the other family, the proband was identified to be heterozygous for this mutation, and a novel mutation, the 341delG in exon 2, was identified. This mutation alters the reading frame and creates a stop codon TAA 15 codons downstream from the mutation, resulting in a truncated protein. Family studies revealed that the father was heterozygous for the 727G-->T mutation and that the mother was heterozygous for the 341delG mutation. This is the first time that the 727G T mutation has been found in Chinese patients or outside Japan. Since we only tested two GSD1a families and found 727G-->T in both, we believe that this mutation may also be prevalent in our local Chinese population. To investigate allele frequencies, we screened 385 Chinese healthy volunteers and found two asymptomatic carriers. Our findings suggest that the 727G-->T mutation is indeed prevalent in Hong Kong.

Thalassemia and G6PD deficiency in Spanish blood donors

Our purpose was to determine the frequency of the thalassemia trait and glucose-6-phosphate dehydrogenase (G6PD) deficiency in blood donors of Madrid, composed of persons from nearly all the Spanish provinces (ranging from 21 to 65 years of age). The frequency of thalassemia and G6PD deficiency has been investigated with the following results; thalassemia 0.92% and no G6PD deficiency. The frequencies observed are compared with those found in the general (non donor) Spanish population. The value of this experiment is considered a supplement to other tests done routinely in our official blood donors.

Hepatic adenoma: MR characteristics and correlation with pathologic findings

OBJECTIVE

The purpose of this study was to describe the MR appearance of hepatic adenomas and correlate the MR imaging features with pathologic findings.

MATERIALS AND METHODS

MR examinations were performed in 14 patients with 66 hepatic adenomas. The diagnosis of hepatic adenoma was proved pathologically in nine patients (22 lesions). In five other patients (44 lesions), who had type I glycogen storage disease and were known to be at risk for hepatic adenomas, the diagnosis was established by repeated sonographic examinations that showed stability, reduction, or resolution of hepatic tumors. T1- and T2-weighted spin-echo MR images obtained at 1.5 T were retrospectively reviewed for the signal intensity of the lesions relative to liver, the signal pattern, the presence of a capsule, and the presence of hemorrhage. Histopathologic specimens (22 lesions) were reviewed for fat content (graded 0-3), the presence of a capsule, and the presence of hemorrhage.

RESULTS

On T1-weighted images, 51 (77%) of 66 lesions were hyperintense, 11 (17%) were hypointense, and four (6%) were isointense with respect to liver. On T2-weighted images, 49 (74%) of 66 lesions were hyperintense, 12 (18%) were isointense, and five (8%) were hypointense. Sixty-one (92%) of 66 lesions were heterogeneous. Eleven (17%) of 66 lesions were hemorrhagic. Of the 22 lesions reviewed histopathologically, 17 were hyperintense on T1-weighted images; 15 of these had a fat content of grade 2 or 3 and two had hemorrhage. All 15 lesions that had a fat content of grade 2 or 3 were hyperintense on T1-weighted images.

CONCLUSION

Hepatic adenomas have a variable MR appearance but most often are hyperintense with respect to liver on T1- and T2-weighted images. The high signal intensity often relates to the increased fat content of these lesions.

Sickle haemoglobin, G-6PD deficiency and malaria in western Orissa

Sixty cases of malaria were screened for sickle haemoglobin and G-6PD deficiency. Plasmodium vivax was detected in 40 (66%) and Plasmodium falciparum in 21 (35%) cases, with six of the latter having cerebral manifestation. Sickle Hb was found in 7 (11.5%) patients and G-6PD deficiency in 3 (5%) cases. Both patients with SS disease had vivax malaria, while of 5 with sickle cell trait 3 had only vivax, one only falciparum and one mixed infection. Amongst G-6PD deficient patients one had vivax and two falciparum malaria. One of the latter had both SC trait and G-6PD deficiency. Thus, adult persons with SS disease or SC trait were not found to be resistant to either vivax or falciparum malaria. A high frequency (5%) of G-6PD deficiency amongst malaria patients warrants a caution against indiscriminate use of 8-aminoquinoline drugs.

G6PD deficiency in neonates: a prospective study

One thousand consecutively born babies were screened for G6PD deficiency and observed for seven days for development of jaundice. Frequency of the deficiency was 3.9%, being 5% in males and 2.8% in females. Religion did not have any bearing on the frequency. Parental screening in cases of babies deficient in G6PD enzyme revealed deficiency of the enzyme in majority of the mothers. Hyperbilirubinemia developed in 48.7% of babies having G6PD deficiency : It is recommended that any neonate presenting with jaundice must be screened for G6PD deficiency not only to define the etiology of hyperbilirubinemia but also to prevent future hemolytic episodes.

Medical problems in Ethiopian refugees airlifted to Israel: experience in 131 patients admitted to a general hospital

Within a 2 month period 131 Ethiopian immigrants were admitted for treatment at a general hospital in Jerusalem. There were 52 patients with malaria, 13 with typhoid fever, 24 with pneumonia, seven with tuberculosis, nine with shigella and 11 with campylobacter. Over three-quarters of these patients were anaemic. In the majority of cases anaemia was normocytic and was most probably secondary to malaria and other intercurrent infections. The prevalence of diffuse non-toxic goitre was 7% in children and 19% in adults with a male to female ratio of 4:13. A positive rapid plasma reagin (RPR) test was found in 4% of sera tested and a positive HBsAg in 13%. IgG antibodies to HBc antigen were found in 75% of subjects. All patients with infectious diseases responded to therapy and, despite their poor condition at arrival, there were no fatalities and no late sequelae. The high HBsAg carrier state calls attention to the risk of vertical transmission by infected mothers and underlines the need for active immunization of infants at risk. The high prevalence of untreated tuberculosis and malaria poses a potential public health hazard, but with the current systematic screening of this population leading to identification and effective treatment of affected subjects, chances for the practical eradication of malaria and tuberculosis are excellent. Finally, the large scale transfer of a population from rural Africa to a modern and largely urban society presents a unique opportunity for a prospective study of the impact of environment on the emergence of diseases which plague modern society such as diabetes, atherosclerotic cardiovascular disease, hypertension and cancer.

Incidence of glycogen storage disease in the German Federal Republic

100 cases of GSD were traced in the GFR. The overall incidence is 1:113000 in proportion to live births. Type I occurs most frequently with 30%, followed by Type II and Type VI with 20% each. Type III is extremely rate in the GFR. 5 cases were classified as glycogenosis with the Fanconi syndrome. With the exception of Type III the type distribution in the GFR was similar to that found in 316 cases in a diagnostic center in Belgium.