GLUT-1DS resistant to ketogenic diet: from clinical feature to in silico analysis. An exemplificative case report with a literature review

Glucose transporter type 1 deficiency syndrome (GLUT-1DS) is characterized by alterations in glucose translocation through the blood-brain barrier (BBB) due to mutation involving the GLUT-1 transporter. The fundamental therapy is ketogenic diet (KD) that provide an alternative energetic substrate - ketone bodies that across the BBB via MCT-1 - for the brain. Symptoms are various and include intractable seizure, acquired microcephalia, abnormal ocular movement, movement disorder, and neurodevelopment delay secondary to an energetic crisis for persistent neuroglycopenia. KD is extremely effective in controlling epileptic seizures and has a positive impact on movement disorders and cognitive impairment. Cases of KD resistance are rare, and only a few of them are reported in the literature, all regarding seizure. Our study describes a peculiar case of GLUT-1DS due to a new deletion involving the first codon of SLC2A1 gene determining a loss of function with a resistance to KD admitted to hospital due to intractable episodes of dystonia. This patient presented a worsening of symptomatology at higher ketonemia values but without hyperketosis and showed a complete resolution of symptomatology while maintaining low ketonemia values. Our study proposes an in-silico genomic and proteomic analysis aimed at explaining the atypical response to KD exhibited by our patient. In this way, we propose a new clinical and research approach based on precision medicine and molecular modelling to be applied to patients with GLUT-1DS resistant to first-line treatment with ketogenic diet by in silico study of genetic and altered protein product.

[Clinical characteristics and ketogenic diet therapy of glucose transporter type 1 deficiency syndrome in children: a multicenter clinical study]

Objective: To explore the clinical characteristics of pediatric glucose transporter type 1 deficiency syndrome (GLUT1 DS), evaluate the efficacy and safety of ketogenic diet therapy (KDT). Methods: Clinical data of 19 children with GLUT1 DS admitted to Children's Hospital of Fudan University, Tianjin Children's Hospital, Shenzhen Children's Hospital, Children's Hospital of Nanjing Medical University and Jiangxi Provincial Children's Hospital between 2015 and 2019 were collected retrospectively. The first onset symptom, main clinical manifestations, cerebrospinal fluid features and genetic testing results of patients were summarized, the efficacy and safety of ketogenic diet treatment were analyzed. Results: Among the 19 cases, 13 were males and 6 females. The age of onset was 11.0 (1.5-45.0) months,the age of diagnosis was 54.0 (2.8-132.0) months. Epilepsy was the first onset symptom of 13 cases. Different forms of tonic-clonic seizures were the most common types of epilepsy (7 cases with generalized tonic-clonic seizures, 5 cases with focal tonic or clonic seizures, 4 cases with generalized tonic seizures). Antiepileptic drugs were effective in 4 cases. Paroxysmal motor dysfunction was present in 12 cases and ataxia was the most common one. All patients had different degrees of psychomotor retardation. Among 17 patients received cerebrospinal fluid examination, cerebrospinal fluid (CSF) glucose level was lower than 2.2 mmol/L and CSF glucose/glycemic index was<0.45 in 16 cases, only 1 case presented normal CSF glucose level (2.3 mmol/L) and normal CSF glucose/glycemic index(0.47). SLC2A1 gene mutations were found in 16 patients, missense, frameshift and nonsense mutations were the common types with 5 cases, 5 cases and 3 cases respectively. All 19 patients were treated with ketogenic diet, which was effective in 18 cases in seizure control, 11 cases in dyskinesia improvement and 18 cases in cognitive function improvement. No serious side effects were reported in any stage of KDT. Conclusions: The diagnosis of GLUT1 DS is often late. It is necessary to improve the early recognition of the disease and perform CSF glucose detection and genetic testing as early as possible. The KDT is an effective and safe treatment for GLUT1 DS, but a small number of patients have not response to diet therapy.

Glucose transporter type 1 deficiency syndrome and the ketogenic diet

Glucose transporter type 1 deficiency syndrome (GLUT1DS) is characterised by deficient glucose transport over the blood-brain barrier and reduced glucose availability in the brain. This causes epilepsy, movement disorders, and cognitive impairment. Treatment with ketogenic diet provides ketones as alternative energy source. However, not all GLUT1DS patients are on dietary treatment (worldwide registry: 77/181 [43%] of patients). The current 25-year experience allows evaluation of effects and tolerability of dietary treatment for GLUT1DS. To this end, literature was searched up to January 2019 for individual case reports and series reporting (side) effects of dietary treatment for GLUT1DS. Upon aggregation of data for analysis, we identified 270 GLUT1DS patients with dietary treatment with a mean follow-up of 53 months. Epilepsy improved for 83% of 230 patients and remained unchanged for 17%, movement disorders improved for 82% of 127 patients and remained unchanged for 17%, and cognition improved for 59% of 58 patients and remained stable for 40%. Effects on epilepsy were seen within days/weeks and were most pronounced in patients with early treatment initiation. Effects on movement disorders were noticed within months and were strongest in patients with higher cerebrospinal fluid-to-blood glucose ratio. Although side effects were minimal, 18% of 270 patients reported poor compliance. In individual patients, symptoms deteriorated upon low ketosis, poor compliance, or treatment discontinuation. Based on the good tolerability and strong favourable effect of dietary treatment on GLUT1DS symptoms, we advocate dietary treatment in all GLUT1DS patients and prompt diagnosis or screening to allow early treatment.

Long-Term Effects of a Classic Ketogenic Diet on Ghrelin and Leptin Concentration: A 12-Month Prospective Study in a Cohort of Italian Children and Adults with GLUT1-Deficiency Syndrome and Drug Resistant Epilepsy

The classical ketogenic diet (cKD) is an isocaloric, high fat, very low-carbohydrate diet that induces ketosis, strongly influencing leptin and ghrelin regulation. However, not enough is known about the impact of a long-term cKD. This study evaluated the effects of a 12-month cKD on ghrelin and leptin concentrations in children, adolescents and adults affected by the GLUT1-Deficiency Syndrome or drug resistant epilepsy (DRE). We also investigated the relationship between the nutritional status, body composition and ghrelin and leptin variations. We carried out a longitudinal study on 30 patients: Twenty-five children and adolescents (15 females, 8 ± 4 years), and five adults (two females, 34 ± 16 years). After 12-monoths cKD, there were no significant changes in ghrelin and leptin, or in the nutritional status, body fat, glucose and lipid profiles. However, a slight height z-score reduction (from −0.603 ± 1.178 to −0.953 ± 1.354, p ≤ 0.001) and a drop in fasting insulin occurred. We found no correlations between ghrelin changes and nutritional status and body composition, whereas leptin changes correlated positively with variations in the weight z-score and body fat (ρ = 0.4534, p = 0.0341; ρ = 0.5901, p = 0.0135; respectively). These results suggest that a long-term cKD does not change ghrelin and leptin concentrations independently of age and neurological condition.

A Rare Cause of Intractable Diarrhea of Infancy

Intractable watery diarrhea presenting in the neonatal period is a relatively uncommon condition. Congenital disorders of malabsorption are among the major causes of prolonged watery diarrhea. This is the case report of a 3-month male infant born to consanguineous parents, who presented with intractable diarrhea since birth. He was failing to thrive and wasted. Persistent diarrhea lead to prolonged hospitalisation and recurrent hypernatremic dehydration. Relevant investigations clinched the diagnosis of ''congenital glucose galactose malabsorption (CGGM)''. The astute clinician should have a high index of suspicion regarding such rare causes of diarrhea in early infancy, as an appropriate rational diagnosis can lead to life-saving treatment as depicted in this case report.

Failure of ketogenic diet therapy in GLUT1 deficiency syndrome

PURPOSE

Epilepsy in GLUT1 deficiency syndrome is generally drug-resistant; ketogenic diet (KD) therapy is the mainstay of therapy, as production of ketones provides the brain with an alternative energy source, bypassing the defect in GLUT1. Failure of KD therapy and risk factors for failure have been sparsely published.

METHODS

We performed a retrospective study of GLUT1DS patients with refractory epilepsy failing on KD therapy, to identify their clinical characteristics.

RESULTS

Failure of the ketogenic diet was due to KD inefficacy (poor effect despite adequate ketosis), as well as intolerance and an inability to attain ketosis. Our cohort of seven patients in whom KD therapy failed stood out for their advanced age at seizure onset, i.e. almost 4 years vs 8 months in large series, female sex, as well as their advanced age at diagnosis and initiation of KD therapy. EEG recordings during KD therapy can aid in the assessment of effectiveness of the KD therapy.

CONCLUSIONS

GLUT1DS is generally described as a treatable disorder and existing case series do not provide details of treatment failure. In select patients with GLUT1DS, KD therapy fails, rendering GLUT1DS an essentially untreatable disorder. Failure of the ketogenic diet was due to KD inefficacy (poor effect despite adequate ketosis), as well as intolerance and an inability to attain ketosis. Failure to reduce seizure frequency with deterioration of the EEG findings should lead to consideration of cessation of KD therapy.

[Exercise and fasting induced movement disorder in children: think of the GLUT1 deficiency syndrome]

BACKGROUND

Glucose transporter type 1 (GLUT1) enables glucose to pass through the blood-brain barrier. A hereditary deficiency of this protein may lead to clinical symptoms when blood glucose levels are decreasing.

CASE DESCRIPTION

A 7-year-old girl with therapy-resistant childhood absence epilepsy presented with an exercise and fasting induced dystonic and atactic movement pattern. The movement pattern disappears postprandial. Based on a reduced glucose in the liquor, and also a reduced liquor glucose/serum glucose ratio, the diagnosis of GLUT1 deficiency syndrome was considered. Through genetic diagnostics a mutation of the SLC2A1 gene was identified, thereby confirming the initial diagnosis. The patient was referred to a tertiary centre for advice on following a ketogenic diet. After initiation of this treatment she no longer experienced absence epilepsy or paroxysmal dyskinesia episodes.

CONCLUSION

GLUT1 deficiency syndrome is a relatively underdiagnosed disease. The recommended therapy is adherence to a ketogenic diet. With this diet the symptoms are treated, yet at the same time the further development of the brain is stimulated.

Disturbed phospholipid metabolism in serine biosynthesis defects revealed by metabolomic profiling

Serine biosynthesis defects are autosomal recessive metabolic disorders resulting from the deficiency of any of the three enzymes involved in de novo serine biosynthesis, specifically phosphoglycerate dehydrogenase (PGDH), phosphoserine aminotransferase (PSAT), and phosphoserine phosphatase (PSP). In this study, we performed metabolomic profiling on 4 children with serine biosynthesis defects; 3 with PGDH deficiency and 1 with PSAT deficiency. The evaluations were performed at baseline and with serine and glycine supplementation. Metabolomic profiling performed at baseline showed low phospholipid species, including glycerophosphocholine, glycerophosphoethanolamine, and sphingomyelin. All children had low serine and glycine as expected. Low glycerophosphocholine compounds were found in 4 children, low glycerophosphoethanolamine compounds in 3 children, and low sphingomyelin species in 2 children. Metabolic profiling with serine and glycine supplementation showed normalization of most of the low phospholipid compounds in the 4 children. Phospholipids are the major component of plasma and intracellular membranes, and phosphatidylcholine is the most abundant phospholipid of all mammalian cell types and subcellular organelles. Phosphatidylcholine is of particular importance for the nervous system, where it is essential for neuronal differentiation. The observed low phosphatidylcholine species in children with serine biosynthesis defects that improved after serine supplementation, supports the role of serine as a significant precursor for phosphatidylcholine. The vital role that phosphatidylcholine has during neuronal differentiation and the pronounced neurological manifestations in serine biosynthesis defects suggest that phosphatidylcholine deficiency occurring secondary to serine deficiency may have a significant contribution to the development of the neurological manifestations in individuals with serine biosynthesis defects.

Inherited Metabolic Disorders: Aspects of Chronic Nutrition Management

The introduction of newborn screening and the development of new therapies have led to an expanding population of patients with inherited metabolic disorders, and these patients are now entering adulthood. Dietary therapy is the mainstay of treatment for many of these disorders, and thus, trained metabolic dietitians are critical members of the multidisciplinary team required for management of such patients. The main goals of dietary therapy in inborn errors of metabolism are the maintenance of normal growth and development while limiting offending metabolites and providing deficient products. Typically, the offending metabolite is either significantly reduced or removed completely from the diet and then reintroduced in small quantities until blood levels are within the normal range. Such treatment is required in infancy, childhood, and adulthood and requires careful monitoring of micronutrient and macronutrient intake throughout the life span. The goal of this review is to highlight the basic principles of chronic nutrition management of the inborn errors of protein, carbohydrate, and fat metabolism.

[Dietary therapy of epilepsy]

Reappraisal of ketogenic diets (KD) were delayed in Japan compared to USA and Korea. The reasons are unknown, but possible explanations are (1) Japanese food culture prefers rice and less fat and (2) ACTH therapy is preferred for West syndrome in Japan. Since Japanese child neurologists were surprised at dramatic effects on glucose transporter 1 deficiency syndrome (Glut-1DS) in 2003, KD have been slowly accepted for treatment of epilepsy in Japan. New generation KD including modified Atkins diet (mAD) are preferred to classical KD. KD can be causal therapy in Glut-1DS and some of mitochondrial disorders, though anti-epileptic drugs are symptomatic therapy. KD can alleviate intractable seizures in epilepsies with brain malformation in addition to West syndrome and Dravet syndrome, etc. KD may work for brain tumor, cancer, neurodegenerative disorders including Alzheimer's disease. C7-8 triglycerides or fatty acid esters are under development as medicines replacing KD.

[Glucose transporter-1 deficiency syndrome can cause various clinical symptoms]

Glucose transporter-1 deficiency syndrome (GLUT1-DS) is caused by a decreased function of the glucose transporter GLUT1 protein, which is located in the blood brain barrier. This leads to inadequate glucose levels for brain metabolism and can cause various clinical symptoms including medically intractable epilepsy, developmental delay and complex movement disorders. Ketonic diet is the golden standard for treatment of GLUT1-DS. GLUT1-DS should be suspected in patients with early-onset intractable epilepsy with developmental delay or activity-induced movement disorders with or without epilepsy.

First report of GLUT1 deficiency syndrome in Chinese patients with novel and hot spot mutations in SLC2A1 gene

Glucose transporter type 1 deficiency syndrome (GLUT1DS) is increasingly recognized as a cause of various neurological disorders but a high index of suspicion is important to make the diagnosis. We report two Chinese patients with GLUT1DS, one of which had a novel mutation in the SLC2A1 gene.

Four cases of long-standing diarrhoea and colic pains cured by fructose-free diet--a pathogenetic discussion

Four patients with a long history of abdominal swelling, colic pains and diarrhoea were cured by a fructose-free diet. They were all given an oral load of (14C) fructose and their expiratory excretion of 14CO2 was found to be significantly lower than that of control patients with similar symptoms. It is concluded taht the patients cured by a fructose-free diet might have a partial fructose malabsorption.

Modified Atkins diet therapy for a case with glucose transporter type 1 deficiency syndrome

Glucose transporter type 1 deficiency syndrome (GLUT-1 DS), giving rise to impaired glucose transport across the blood-brain barrier, is characterized by infantile seizures, complex motor disorders, global developmental delay, acquired microcephaly, and hypoglycorrhachia. GLUT-1 DS can be treated effectively with a ketogenic diet because it can provide an alternative fuel for brain metabolism; however, the excessive restriction of food intake involved frequently makes it difficult for patients to initiate or continue the diet. Recently, the modified Atkins diet, which is much less restrictive in terms of the total calorie and protein intake than the classical ketogenic diet, has been shown to be effective and well tolerated in children with intractable epilepsy. We successfully introduced the modified Atkins diet to a 7-year-old boy with GLUT-1 DS, whose caregivers refused ketogenic diet treatment because of strong concerns over restricting the diet. The modified Atkins diet should be considered for patients with GLUT-1 DS as an alternative to the traditional ketogenic diet.

[Glucose transponer type 1 deficiency síndrome (GLUT-1 SD) treated with ketogenic diet. Report of one case]

The glucose transporter type 1 deficiency syndrome (GLUT-1 SD) (OMIM 606777) is an inborn error of metabolism of brain glucose transport. The characteristic clinical manifestations are seizures, hypotonia, developmental delay, microcephaly and hypoglycorrhachia. We report a girl with normal weight and height at birth. At 6 weeks of age she started with convulsions reaching up to 20 myoclonic seizures a day. She was treated with valproate, phenobarbital and carbamazepine without response. Blood analysis including aminoacids and acylcarnitines were all normal. The brain MRI showed frontal atrophy with an increased subarachnoidal space and Electroencephalography was abnormal. Blood glucose was 84 mg/dl and spinal fluid glucose 26 mg/dl with a ratio of 0.31 (Normal Ratio >0.65+/-00.1). These results suggested the diagnosis of GLUT-1 SD, and was confirmed with erythrocyte glucose uptake of 44% (Normal range 80-100%). A molecular study found the mutation 969del, C971T in exon 6 of the gene Glut-1. Treatment with a ketogenic diet was started immediately and after 7 days with this diet seizures ceased. Anticonvulsants were progressively suspended. At present, the patient is 6 years old, she continues on a ketogenic diet and supplements with L-carnitine, lipoic acid, vitamins and minerals. Growth and development are normal with an intelligence quotient of 103. It is concluded that it is necessary to include GLUT-1 SD in the differential diagnosis of children with early seizures that are non responsive to pharmacological treatment.

Three Japanese patients with glucose transporter type 1 deficiency syndrome

We report three Japanese patients with glucose transporter type 1 deficiency syndrome (Glut1DS). Two patients had a normal erythrocyte 3-O-methylglucose (3OMG) uptake, one with a previously reported T295M substitution and the other with a novel 12-bp insertion at nt 1034-1035, ins CAGCAGCTGTCT. The third patient, with deficient 3OMG uptake, had a previously reported hot-spot mutation, R333W. All three patients responded to a ketogenic diet. All patients showed a significant improvement in ataxia, with blood beta-hydroxybutyrate (BOHB) levels ranging from 0.1 to 3mM. BOHB levels of at least 3mM were necessary to control seizures, and higher ketone levels are recommended to meet brain energy needs during development. FDG-PET scan, performed before and after a ketogenic diet in the R333W patient, did not change despite a clinical improvement. This clinical condition is treatable and early diagnosis is important.

Seizures, ataxia, developmental delay and the general paediatrician: glucose transporter 1 deficiency syndrome

AIM

Glucose transporter 1 deficiency syndrome (GLUT1-DS) is an important condition for the general paediatrician's differential armamentarium. We describe a case series of eight patients in order to raise awareness of this treatable neurometabolic condition. The diagnosis of GLUT1-DS is suggested by a decreased absolute cerebrospinal fluid (CSF) glucose value (<2.2 mmol/L) or lowered CSF: plasma glucose ratio (<0.4).

METHODS

This is a review of eight Queensland patients with GLUT1-DS. The clinical presentation, clinical course, laboratory investigations and treatment outcomes are discussed.

RESULTS

The clinical features noted in our patient cohort include combinations of ataxia, developmental delay and a severe seizure disorder that is refractory to anticonvulsant medications. Seizures are the most common clinical manifestation and may be exacerbated by phenobarbitone. The paired CSF: plasma glucose results ranged from 0.2 to 0.39 (normal <0.6) with an average of 0.33. 3-O-Methyl-D-Glucose uptake and GLUT1 Genotyping analysis have been performed on five patients thus far. Rapid and impressive seizure control was observed in 100% of our patients once the ketogenic diet was instituted, with half of the cohort being able to wean completely from anticonvulsants.

CONCLUSION

Children presenting with a clinical phenotype consisting of a refractory seizure disorder, ataxia and developmental delay should prompt the consideration of Glucose transporter 1 deficiency syndrome. While the diagnostic test of lumbar puncture is an invasive manoeuvre, the diagnosis provides a viable treatment option, the ketogenic diet. GLUT1-DS displays clinical heterogeneity, but the value of early diagnosis and treatment is demonstrated by our patient cohort.

GLUT-1 deficiency without epilepsy--an exceptional case

The GLUT-1 deficiency is a metabolic disorder caused by a defect in glucose transport across the blood-brain barrier as a result of a defect in the glucose-transport protein. Patients present with epileptic seizures, delayed development, ataxia and hypotonia, and in many cases acquired microcephaly. In most patients, treatment with a ketogenic diet proved to be successful in controlling the epilepsy. We report a 9-year-old boy with retardation and ataxia, but without epilepsy, caused by GLUT-1 deficiency, proven biochemically and by DNA analysis. Treatment with a medium-chain triglyceride ketogenic diet had a beneficial effect.

[The effect of an antiatherosclerotic diet including omega-3 polyunsaturated fatty acids of marine and plant origins on the indices of cellular and humoral immunity in patients with ischemic heart disease and a disordered carbohydrate tolerance]

The dynamic of natural antibodies against catecholamines and alpha-2-macroglobulin, thrombin, antithrombin III and parameters of cellular immunity in 92 patients with ischemic heart disease and ischemic heart disease complicated by impaired glucose tolerance was studied of influence of antiatherosclerotic diet with fish and vegetable PUFA omega-3 from "Eicolen". Besides favorable influence to a clinical picture of the disease universal normalizing influence of antiatherosclerotic diet with addition Eicolen on parameters of humoral a cellular immunity.

Clinical and pathologic findings in two draft horses with progressive muscle atrophy, neuromuscular weakness, and abnormal gait characteristic of shivers syndrome

Two Belgian geldings, 4 and 14 years old, respectively, with muscle atrophy, weakness, and abnormal gait characteristic of severe advanced shivers were examined clinically and on necropsy. Neurologic examination revealed no evidence of ataxia, and the clinical diagnosis was neuromuscular weakness and shivers. Necropsies of both horses, including examination of pituitary, brain, spinal cord, spinal roots and ganglia, and peripheral nerves, revealed no gross or histologic abnormalities. Examination of multiple skeletal muscle specimens revealed chronic myopathic changes and periodic acid-Schiff positive, amylase-resistant inclusions within muscle fibers, characteristic of equine polysaccharide storage myopathy. It is suggested that underlying metabolic myopathy may be the cause of muscle weakness and cramping in horses with shivers.

Human glycosylation disorders and sugar supplement therapy

Some genetic defects in protein glycosylation can be treated effectively with dietary supplements of monosaccharides. An easy screening test and non-toxic therapy for potentially lethal disorders should encourage physicians to search for more patients with glycosylation disorders. It should also stimulate research on the occurrence and availability of monosaccharides used for glycoconjugate synthesis and for vertebrate models to study their utilization.

Nutrition management of congenital glucose-galactose malabsorption: a case study

In this article we describe the clinical history, diagnostic evaluation, and management of an infant who had congenital glucose-galactose malabsorption (CGGM)--a rare disorder thought to be inherited as an autosomal recessive trait. Because of defective sodium-coupled cotransport of glucose and galactose in the intestinal mucosa, infants with CGGM suffer from chronic, profuse, watery diarrhea that often leads to hypertonic dehydration. This infant experienced persistent diarrhea and hypernatremic dehydration during the first 3 months of life. Despite management with elemental formulas and continuous nasogastric feedings during initial hospitalizations, worsening diarrhea and dehydration persisted and malnutrition occurred. Diagnostic evaluations ruled out cystic fibrosis and bacterial or viral gastroenteritis. Diagnostic tests also revealed normal pancreatic exocrine function and normal villus architecture. The persistence of glucose-positive, watery diarrhea, even when the infant was fed an oral electrolyte solution, led to the diagnosis of CGGM. The infant was treated successfully with a carbohydrate-free infant formula to which fructose was added incrementally to meet energy requirements. Parental education about dietary management of CGGM with specialized formula supplemented with fructose and solid food feedings was an important component of this infant's nutrition therapy. Aggressive nutrition intervention for the infants and judicious dietary counseling for parents can lead to normal growth and neurological development for an infant with CGGM.

Glucose-galactose malabsorption with renal stones in a Saudi child

A case of glucose-galactose malabsorption in an 18-month-old Saudi girl is presented. She had associated bilateral renal stones with impaired renal function. Dietary therapy improved her malabsorption and the renal stones were cleared by extracorporeal shortwave lithotripsy.

Complex carbohydrate intolerance: diagnostic pitfalls and approach to management

Complex carbohydrate intolerance occurred in three of 105 patients with protracted diarrhea of infancy. Nosocomial gastroenteritis complicated a primary disorder of carbohydrate absorption (primary glucose galactose malabsorption, two; primary sucrase isomaltase deficiency, one) in all patients. Their course was characterized by protracted diarrhea, variable degrees of villus atrophy on intestinal biopsy tissue, and negative caloric balance requiring intravenous alimentation for periods varying from 6 to 16 weeks. Dietary management required rigid exclusion of all offending carbohydrates from the diet. Delay in the diagnosis of primary carbohydrate intolerance varied from 2 weeks to 6 months. Complex carbohydrate intolerance may be more common than has been reported, and should be considered in all infants with protracted diarrhea of infancy when there is persistent carbohydrate intolerance.

Diet therapy in gastrointestinal disease: a commentary

Dietary regimens in gastrointestinal disease can be divided into two categories: First, those of proven value include: (a) Disaccharide elimination for disaccharidase deficiency and exclusion of monosaccharides for sugar malabsorption; (b) gluten-free diet for celiac/sprue; (c) elimination of certain allergens because of food allergies; (d) protein restriction for portal systemic encephalopathy; (e) low-carbohydrate diet for dumping syndrome; (f) low-fiber diet for diarrheal syndromes; and (g) low-fat diet for steatorrhea. Second, controversial diets include a bland diet for acid-peptic disorders, a high-fiber diet for colonic disorders, and a low-fat diet for gallbladder disease. It is important to separate facts from fancy in the dietary management of patients with gastrointestinal disease and base the recommendations for a particular diet on available objective evidence, not on traditional or fashionable trends.

Galactose-1-phosphate accumulation by a Duarte-transferase deficiency double heterozygote

An infant, suspected of having galactosemia following a positive screening test on dried blood spots, was shown to be a Duarte-transferase deficiency compound heterozygote through studies of electrophoretic mobility of the transferase enzyme in blood from the patient and family members. No rise in blood glucose was seen following oral ingestion of galactose. At the same time, galactose rose in plasma and was excreted in the urine; galactose-1-phosphate accumulated in erythrocytes. A galactose-free diet was considered the prudent course in the presence of the patient's inability to metabolize galactose completely.

The clinical and biochemical implications of pyruvate carboxylase deficiency

A 10 month old female infant was evaluated for severe lactic acidosis. Clinically she was well nourished and had a substantial amount of adipose tissue despite recurrent episodes of acidosis. Her psychomotor development was retarded, her movements were dystonic and generalized seizures punctuated her course. Metabolic abnormalities included elevated blood concentrations of lactate, pyruvate, beta-hydroxybutyrate, acetoacetate, alanine, proline and glycine, decreased blood concentrations of glutamine, aspartate, valine and citrate, and intermittent elevations of serum cholesterol. A trial on a high-fat diet worsened the clinical condition and intensified the ketoacidosis and hyperalaninemia. Analysis of hepatic tissue obtained by open biopsy revealed increased concentrations of lactate, alanine, acetyl-CoA and other short-chain acyl-CoA esters, and decreased concentrations of oxaloacetate, citrate, alpha-ketoglutarate, malate and aspartate. The blood and tissue metabolic perturbations reflected a deficiency of hepatic pyruvate carboxylase. The apparent Km of hepatic citrate synthase for oxaloacetate was 4.6 micrometer. Calculated tissue oxaloacetate concentrations were 0.50--0.84 micrometer suggesting that tricarboxylic acid cycle activity was severely limited by the decreased availability of this substrate. An iv glucose tolerance test resulted in the paradoxical synthesis of ketone bodies. This observation, coupled with the intermittent hypercholesterolemia and the increased tissue acetyl-CoA concentrations, suggests that pyruvate carboxylase is important in modulating the fractional distribution of intracellular acetyl-CoA between the tricarboxylic acid cycle, the beta-hydroxy-beta-methyl-glutaryl-CoA cycle (and the synthesis of cholesterol and ketone bodies), and fatty acid synthesis. Treatment in future cases might be directed toward increasing tissue concentrations of oxaloacetate.

Disorders of galactose metabolism

Galactose metabolism occupies a central position in modern biology through its relationship to cell surface antigenicity and its metabolic function as a component of glycolipids and glycoproteins. Disturbances in three fundamental reaction sequences of this hexose have led to a delineation of pathways of the chemistry resulting in the understanding of its metabolic fate. These inherited disorders of metabolism are prototypes for the application of nutritional therapy of biochemical genetic defects.

[Normal nutrition--malnutrition during malassimilation?]

Intestinal resorption can be disturbed in its intraluminal, intracellular or postcellular phase. Any such dysfunction may lead to an isolated or global malabsorption syndrome. An exact elucidation of the underlying pathophysiology is a prerequisite for a rational diet prescription. Only when this is completed, the diet can be adapted in a quantitative and qualitative sense to the residual intact function of the diseased digestion or absorption organ. The dietetic measures in an isolated or global malabsorption syndrome have been discussed.

Ketonic diet in the management of pyruvate dehydrogenase deficiency

Two brothers, aged 11 years 6 months and 2 years 3 months, with psychomotor and growth retardation, episodes of weakness, ataxia, ophthalmoplegia, and elevated levels of blood pyruvate were shown to have a deficiency in the pyruvate dehydrogenase complex (PDH). When they ate a diet high enough in fats to cause ketonemia but not acidosis, there was a fall in blood pyruvate levels, a decrease in the frequency and severity of the episodes of neurological deterioration, an increased rate of growth and development in the younger brother, and increased strength and endurance in the older one. The possibility of dietary treatment makes the early diagnosis of PDH deficiency more important. Determination of blood pyruvate and lactate levels following a standard glucose meal (glucose-pyruvate test) appears to be the most reliable screening test for this condition.

Out-patient dietary management in the Prader-Willi syndrome

Dietary adherence of eight children with the Prader-Willi syndrome was studied in the home environment. Weight changes were recorded at two-week intervals, and measured two-week dietary records were completed twice during the study by the parents of seven of the children. An eighth child was similarly followed for three months, and one dietary record was obtained. Calories, protein, fat, and carbohydrate contents were calculated, and related to recorded weight changes to determine which diets were most practical in controlling weight gain. Caloric requirements of children with the Prader-Willi syndrome appear to be much lower than those of healthy, active children of comparable ages. Age, degree of obesity, familial relationships, and probably, composition of the diet influenced the effectiveness of a given diet. Each family designed a diet which took into consideration the family's eating habits, as well as the needs of the Prader-Willi child. Frequent contact with the dietitian enabled each family to try new food preparation ideas. The effectiveness and acceptability of a low caloric, very low-carbohydrate diet should be tested over long periods in Prader-Willi children whose obesity is being managed in a non-institution setting.

[Neonatal lactic acidosis and hypoglycemia due to a congenital hepatic fructose-1,6-diphosphatase deficiency]

Famialial defect of hepatic fructose-1,6-diphosphatase. Diagnosis was suspected in a male newborn since a brother was also concerned by the disease. The disease may be therefore diagnosed early, when the onset is neonatal. In the neonatal distress syndromes due to hereditery disorders of metabolism, a semiologic field may be isolated in which symptoms begin after an interval of short duration with hypoglycemia, hepatomegaly, lactic acidosis and ketosis ("enlarged liver hypoglycemia"). This possibility leads first to a symptomatic treatment of hypoglycemia and acidoketosis, then to the feeding with human milk and simple functional tests for the diagnostic approach.