Impaired bone metabolism in glycogen storage disease type 1 is associated with poor metabolic control in type 1a and with granulocyte colony-stimulating factor therapy in type 1b

BACKGROUND

Glycogen storage disease type 1 (GSD1) is a rare and genetically heterogeneous metabolic defect of gluconeogenesis due to mutations of either the G6PC gene (GSD1a) or the SLC37A4 gene (GSD1b). Osteopenia is a known complication of GSD1.

OBJECTIVES

The aim of this study was to investigate the effects of poor metabolic control and/or use of GSD1-specific treatments on bone mineral density (BMD) and metabolism in GSD1 patients.

METHODS

In a multicenter, cross-sectional case-control study, we studied 38 GSD1 (29 GSD1a and 9 GSD1b) patients. Clinical, biochemical and instrumental parameters indicative of bone metabolism were analyzed; BMD was evaluated by dual-emission X-ray absorptiometry and quantitative ultrasound.

RESULTS

Both GSD1a and GSD1b patients showed reduced BMD compared with age-matched controls. In GSD1a patients, these abnormalities correlated with compliance to diet and biochemical indicators of metabolic control. In GSD1b patients, BMD correlated with the age at first administration and the duration of granulocyte colony-stimulating factor (G-CSF) therapy.

CONCLUSIONS

Our data indicate that good metabolic control and compliance with diet are highly recommended to improve bone metabolism in GSD1a patients. GSD1b patients on G-CSF treatment should be carefully monitored for the risk of osteopenia/osteoporosis.

Epilepsy in inherited metabolic disorders: a pediatric series

AIM

Our study aims at further defining the characteristics of epilepsy in Inherited Metabolic Disorders (IMDs).

METHODS

We reviewed the medical records of 345 patients with IMDs followed at the Metabolic Diseases Unit of our Department of Pediatrics and found the presence of an epileptic syndrome in 45 cases. An overview is given based on various criteria such as pathogenetic background, seizure type, age of onset, EEG, neuroimaging data, treatability. Seizure types were: focal (24 patients), generalized (13 patients), febrile (3 patients), and hypoglycemic (8 patients with glycogenoses). Some patients presented with more than one type of seizures. Age of onset was mainly during the first year of life (N.=19), between 2 and 6 years in 13 patients, and after the 6th year in 9 patients.

RESULTS

Available EEGs showed either focal (N.=21) or generalized epileptiform abnormalities (N.=11); multifocal paroxysms were evident in 3 patients while the remaining 3 patients had normal findings. Available neuroimages (CT/MRI) showed either normal findings (N.=6) or white matter abnormalities (N.=6), cerebral and/or cerebellar cortical atrophy (N.=11), hydrocephalus (N.=1), corpus callosum hypoplasia (N.=2), pontocerebellar hypoplasia (N.=1), gliosis in trigone area (N.=4). Most patients showed a favorable response to antiepileptic treatment (AEDs) with either complete control or reduced seizure frequency.

CONCLUSION

IMDs are a relatively rare cause of epilepsy in children but their diagnosis is very important with respect to treatment, prognosis and genetic counselling.

Developmental evolution in a patient with multiple acyl-coenzymeA dehydrogenase deficiency under pharmacological treatment

PURPOSE

evaluate the psychomotor evolution of a child with Multiple acyl-CoA dehydrogenase deficiency after treatment with L-carnitine, ubiquinone and riboflavin.

METHODS

an assessment of psychomotor development was performed before the start of farmacological treatment using the Assessment Scale of Mental Development Griffiths (GMDS-R, 0-2 years). The same assessment was performed after a month and after six months of treatment to evaluate the possible benefits of treatment.

RESULTS

we noticed a quick and dramatic improvement in muscular tone and motor performances after pharmacological treatment. We also observed a substantial improvement in the personal/social and hearing/language areas, suggesting the presence of intellectual/cognitive improvement. The clinical improvement correlated with the biochemical response.

CONCLUSION

In our patient early therapy resulted in a optimal response in psychomotor development, motor function and muscole hypotonia. Evaluation with GMDS-R, a simple, non-invasive and multidimensional tool, represents a useful instrument to monitor the clinical response to treatment.

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/mm(3) 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.

Myasthenia gravis in a patient affected by glycogen storage disease type Ib: a further manifestation of an increased risk for autoimmune disorders?

Glycogen storage disease type Ib (GSD Ib, OMIM 232220) is an inborn disorder of glucose metabolism, caused by mutations in the G6PT gene, encoding a glucose 6-phosphate transporter (G6PT). GSD Ib is mainly associated with fasting hypoglycaemia and hepatomegaly. Most GSD Ib patients also show neutropenia and neutrophil dysfunction and therefore are at risk of developing severe infections and inflammatory bowel disease (IBD). An increased risk for autoimmune disorders, such as thyroid autoimmunity and Crohn-like disease, has also been demonstrated, but no systematic study on the prevalence of autoimmune disorders in GSD Ib patients has ever been performed. We describe a 25-year-old patient affected by GSD Ib who developed 'seronegative' myasthenia gravis (MG), presenting with bilateral eyelid ptosis, diplopia, dysarthria, severe dysphagia, dyspnoea and fatigue. The repetitive stimulation of peripheral nerves test showed signs of exhaustion of neuromuscular transmission, particularly evident in the cranial area. Even in the absence of identifiable anti-acetylcholine receptor antibodies, seronegative MG is considered an autoimmune disorder and may be related to the disturbed immune function observed in GSD Ib patients.

HHH syndrome (hyperornithinaemia, hyperammonaemia, homocitrullinuria), with fulminant hepatitis-like presentation

We report a 3-year-old Italian patient with the hyperornithinaemia, hyperammonaemia, homocitrullinuria (HHH) syndrome who presented with neurological deterioration after an intercurrent infection. Hyperammonaemia, coagulopathy and moderate hypertransaminasaemia were detected on hospital admission. Severe hepatocellular necrosis with hypertransaminasaemia (aspartate aminotransferase 20,000 UI/L, alanine aminotransferase 18,400 UI/L) and coagulopathy (PT < 5%) rapidly developed within few days, prompting evaluation for liver transplantation. A protein-restricted diet and arginine supplementation were immediately started, with a rapid improvement of the patient's neurological conditions and normalization of liver function tests and blood ammonia. The diagnosis of HHH syndrome was based on the presence of the typical metabolic abnormalities. Molecular analysis of the SLC25A15 gene showed that the patient was heterozygous for two novel mutations (G113C and M273K). The diagnosis of HHH syndrome should be considered in patients with fulminant hepatitis-like presentations. Early identification and treatment of these patients can be life-saving and can avoid liver transplantation.

Efficacy of ACE-inhibitor therapy on renal disease in glycogen storage disease type 1: a multicentre retrospective study

BACKGROUND

The efficacy of ACE-inhibitors in decreasing microalbuminuria and proteinuria has been reported in a few patients with glycogen storage disease type 1 (GSD1); however, no case-control study has ever been published.

AIM

The aim of the current study was to evaluate the efficacy of ACE-inhibitors in reducing glomerular hyperfiltration, microalbuminuria and proteinuria, and in delaying the progression of renal damage.

PATIENTS AND METHODS

Ninety-five patients (median age at the time of the study: 14.5 years) were enrolled from nine Italian referral centres for metabolic diseases. A retrospective study of a 10-year follow-up was conducted in order to compare the evolution of these parameters in treated patients with those who were not treated with ACE-inhibitors.

RESULTS

A significant and progressive decrease of glomerular filtration rate was observed in treated patients vs. those who were not treated with ACE-inhibitors (P < 0.05). No difference was observed for microalbuminuria and proteinuria between the two groups of patients. Moreover, the ACE-inhibitors significantly delayed the progression from glomerular hyperfiltration to microalbuminuria, but not that from microalbuminuria to proteinuria.

CONCLUSIONS

The results of the present study underline the importance of a strict follow-up of renal function in GSD1 patients. The detection of glomerular hyperfiltration suggests precocious initiation of ACE-inhibitor treatment to delay the progression of renal damage. A randomized prospective study is needed to establish for certain the real effectiveness of this treatment in GSD1 patients.

Vitamin D status in patients affected by Smith-Lemli-Opitz syndrome

Smith-Lemli-Opitz syndrome (SLOS) is an inborn error of cholesterol biosynthesis characterized by developmental delay and multiple malformations. Some of the patients have skin photosensitivity and therefore tend to avoid direct exposure to sunlight.SLOS patients typically have low concentrations of cholesterol and abnormally high concentrations of its precursor 7-dehydrocholesterol (7-DHC) in biological fluids and tissues. 7-DHC is also a precursor in the cutaneous synthesis of vitamin D. Sunlight exposure plays a major role in this pathway and reactions transforming 7-DHC into vitamin D and then into 25-hydroxyvitamin D are known not to be specifically regulated. The aim of this study was to evaluate vitamin D status in SLOS patients. We measured 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D serum concentrations and markers of calcium metabolism in five SLOS patients. Despite abnormally high concentrations of 7-DHC, circulating concentrations of vitamin D metabolites were not significantly different from appropriate controls matched for sex, age and season of blood collection. The analysis of historical serum samples stored in our laboratory from the same cases plus 10 other SLOS patients further supported these findings. Our data suggest that SLOS patients have a peculiar vitamin D metabolism that protects them from vitamin D intoxication. This appears to be due in most cases to decreased transformation of 7-DHC into 25-hydroxyvitamin D, perhaps depending on reduced sunlight exposure as a consequence of photosensitivity. Possible alternative mechanisms are discussed.

Crohn's-like ileo-colitis in patients affected by glycogen storage disease Ib: two years' follow-up of patients with a wide spectrum of gastrointestinal signs

AIM

To investigate the presence of inflammatory bowel disease (IBD) and to evaluate the progression of bowel involvement after two years' follow-up in seven patients affected by glycogen storage disease type Ib (GSDIb).

METHODS

Seven patients (5F, 2M, aged 4.5-20.6 y) entered the study. Bowel involvement was evaluated by ileocolonoscopy and specific IBD serologic markers. To evaluate disease activity, Paediatric Crohn's Disease Activity Index (PCDAI), terminal ileum wall thickness detected at ultrasonography (US), 99mTechnetium labelled autologous White Cell Scan (Tc-WCS) and barium meal with follow-through were investigated.

RESULTS

Ileocolonoscopy and histology examination revealed variable degrees of bowel involvement in all patients. The results of serologic markers were indicative of a Crohn's-like ileocolitis. US and Tc-WCS, could clearly define patients with severe inflammatory involvement, but failed to identify all patients with mild to moderate disease. For the most severely affected patients, anti-inflammatory agents and steroids were prescribed, whereas nutritional therapy with polymeric formula and antibiotics were assumed by two other patients and antibiotics only by one patient. Granulocyte colony-stimulating factor (G-CSF) was prescribed to all patients. Ileocolonoscopy and histology data improved in all patients. The assumption of G-CSF and/or gastric drip feeding (g.d.f.) was inversely associated with the PCDAI results (p < 0.05).

CONCLUSION

IBD is common in patients affected by GSDIb independently of the severity of gastrointestinal signs and symptoms. Different therapeutic approaches can be used according to the severity of IBD. G-CSF treatment and g.d.f. can be protective factors for IBD.

Geleophysic dysplasia: 7-year follow-up study of a patient with an intermediate form

Geleophysic dysplasia (MIM *231050) is a rare autosomal recessive disorder, characterized by short stature with short limbs, brachydactyly, joint contractures, and a good-natured facial appearance. Infiltration of liver and cardiac leaflets has been reported in some patients. Based on the clinical picture and the detection of lysosome-like inclusions in hepatocytes, tracheal mucosa, chondrocytes, and skin fibroblasts, the underlying cause of the conditions is considered to be a generalized lysosomal storage defect. We report on a new case born to consanguineous parents, first observed at age 8 months, and for whom a 7-year follow-up is available.

Molecular and cytogenetic characterization of a recurrent unbalanced translocation (4;21)(p16.3;q22.1): relevance to the Wolf-Hirschhorn and Down syndrome critical regions

We report on an aneuploidy syndrome due to the unbalanced segregation of a familial translocation (4;21)(p16.3;q22.1) causing a partial 4p monosomy and a partial 21q trisomy. The three affected children presented with severe failure to thrive, short stature, microcephaly, profound hypotonia, and mental retardation. The face, very similar in the three children, is characterized by frontal bossing, upslanting of the palpebral fissures, short nose, and deep set ears, giving the overall appearance of the Down syndrome. The molecular study has defined the aneuploid segment on both 4p and 21q. Most of the Down syndrome critical region was found to the trisomic, while only part of the candidate Wolf-Hirschhorn syndrome critical region was deleted, suggesting that this region is not critical for the major malformations characteristic for WHS.