International practices in the dietary management of fructose 1-6 biphosphatase deficiency.

BACKGROUND: In fructose 1,6 bisphosphatase (FBPase) deficiency, management aims to prevent hypoglycaemia and lactic acidosis by avoiding prolonged fasting, particularly during febrile illness. Although the need for an emergency regimen to avoid metabolic decompensation is well established at times of illness, there is uncertainty about the need for other dietary management strategies such as sucrose or fructose restriction. We assessed international differences in the dietary management of FBPase deficiency. METHODS: A cross-sectional questionnaire (13 questions) was emailed to all members of the Society for the Study of Inborn Errors of Metabolism (SSIEM) and a wide database of inherited metabolic disorder dietitians. RESULTS: Thirty-six centres reported the dietary prescriptions of 126 patients with FBPase deficiency. Patients' age at questionnaire completion was: 1-10y, 46% (n = 58), 11-16y, 21% (n = 27), and >16y, 33% (n = 41). Diagnostic age was: <1y, 36% (n = 46); 1-10y, 59% (n = 74); 11-16y, 3% (n = 4); and >16y, 2% (n = 2). Seventy-five per cent of centres advocated dietary restrictions. This included restriction of: high sucrose foods only (n = 7 centres, 19%); fruit and sugary foods (n = 4, 11%); fruit, vegetables and sugary foods (n = 13, 36%). Twenty-five per cent of centres (n = 9), advised no dietary restrictions when patients were well. A higher percentage of patients aged >16y rather than ≤16y were prescribed dietary restrictions: patients aged 1-10y, 67% (n = 39/58), 11-16y, 63% (n = 17/27) and >16y, 85% (n = 35/41). Patients classified as having a normal fasting tolerance increased with age from 30% in 1-10y, to 36% in 11-16y, and 58% in >16y, but it was unclear if fasting tolerance was biochemically proven. Twenty centres (56%) routinely prescribed uncooked cornstarch (UCCS) to limit overnight fasting in 47 patients regardless of their actual fasting tolerance (37%). All centres advocated an emergency regimen mainly based on glucose polymer for illness management. CONCLUSIONS: Although all patients were prescribed an emergency regimen for illness, use of sucrose and fructose restricted diets with UCCS supplementation varied widely. Restrictions did not relax with age. International guidelines are necessary to help direct future dietary management of FBPase deficiency.

First on-line survey of an international multidisciplinary working group (MightyMedic) on current practice in diagnosis, therapy and follow-up of dyslipidemias.

The MightyMedic (Multidisciplinary International Group for Hemapheresis TherapY and MEtabolic DIsturbances Contrast) Working Group has been founded in 2013. The leading idea was to establish an international network of interdisciplinary nature aimed at working to cross national borders research projects, clinical trials, educational initiatives (meetings, workshops, summer schools) in the field of metabolic diseases, namely hyperlipidemias, and diabetes, preventive cardiology, and atherosclerosis. Therapeutic apheresis, its indications and techniques, is a parallel field of investigation. The first on-line survey of the Group has been completed in the first half of 2014. The survey included # 24 Centers in Italy, Germany, Greece, UK, Sweden, Japan and USA. Relevant data have been collected on current practice in diagnosis, therapy and follow-up of dyslipidemias. 240 subjects with hyperlipidemia and treated with lipoprotein apheresis have been reported in the survey, but a large percentage of patients (35%) who could benefit from this therapeutic option are still treated by conventional drug approach. Genetic molecular diagnosis is performed in only 33% of patients while Lipoprotein(a) (Lp(a)) is included in cardiovascular disease risk assessment in 71% of participating Centers. New detailed investigations and prospective multicenter studies are needed to evaluate changes induced by the impact of updated indications and strategies, as well as new treatment options, targeting standardization of therapeutic and diagnostic approaches.

Analysis of low density lipoprotein receptor gene mutations and microsatellite haplotypes in Greek FH heterozygous children: six independent ancestors account for 60% of probands.

This study reports the characterization of 60% of low density lipoprotein receptor (LDLR) gene mutations in 150 unrelated Greek familial hypercholesterolaemia (FH) heterozygous children by the analysis of six LDLR gene mutations. The linkage disequilibrium of two polymorphic microsatellites (D19S394 and D19S221) flanking the LDLR gene on chromosome 19 to the four most common mutations strongly suggests that each mutation is identical-by-descent in the probands included in this study (this is also supported by the geographical distribution of FH families with these mutations throughout Greece) and permits an estimation of the number of generations from a common ancestor for each mutation. The characterization of 60% of LDLR mutations in a representative sample of Greek FH heterozygotes provides a basis for the diagnosis of FH through DNA analysis in Greece, by using single-strand conformation polymorphism analysis followed by allele-specific oligonucleotide hybridization (exon 6 mutations) or restriction endonuclease analysis (C152R, V408M). A rapid diagnostic assay positive for the mutation has been developed for the most common mutation, G528D. The application of simple DNA diagnostic assays for LDLR mutation analysis are appropriate for the early identification of FH heterozygotes in Greece and are useful for the primary prevention of coronary artery disease.

Oral manifestations in glycogen storage disease type 1b.

Glycogen storage disease type 1b is a rare metabolic disorder which affects the transport system of glucose-6-phosphatase metabolism. As a result, hepatomegaly, failure to thrive, renal dysfunction and recurrent infections occur in affected patients. In this paper, the oral complications in three children with glycogen storage disease type 1b are discussed. Oral ulcers were a common finding, probably due to severe neutropenia and impaired neutrophil migration which characterises the onset of this rare disorder.

Late onset ornithine carbamoyl transferase deficiency in males.

Six boys with ornithine carbamoyl transferase deficiency presenting in infancy or later childhood are described. There was wide variation in both the time of presentation and the symptoms, which may initially suggest a neurological, behavioural, or gastroenterological problem. Two patients died, as did two male siblings who were probably affected, but with early recognition of the hyperammonaemia the outlook is good.

Timing of strict diet in relation to fetal damage in maternal phenylketonuria. An international collaborative study by the MRC/DHSS Phenylketonuria Register.

64 infants born to women with phenylketonuria (PKU) were grouped according to the mother's dietary treatment in pregnancy. 17 infants, whose mothers were receiving a strict low phenylalanine diet and had blood phenylalanine concentrations below 600 mumol/l at the time of conception, had normal birthweights and head circumferences and no malformations. In the 29 infants whose mothers were receiving either a relaxed diet or a normal diet at conception but who started a strict diet at some time during pregnancy, birthweights and head circumferences were below those in healthy infants and there was an excess of malformations; the findings closely resembled those for the 18 infants whose mothers received no treatment during pregnancy. The birthweights and head circumferences of the 64 infants were inversely related to the maternal phenylalanine concentrations around the time of conception. Only a strict diet started before conception is likely to prevent fetal damage.