Glycogen storage disease type III (GSD III) due to debranching enzyme deficiency presenting usually with hepatomegaly and hypoglycemia may be responsible for severe cardiomyopathy which is often fatal. Current treatment of GSD III is based on frequent high-carbohydrate meals that have no effect on the cardiomyopathy. We describe a 2-mo-old infant presenting with a familial form of GSD III complicated with cardiomyopathy. As conventional treatment was unable to improve his sister's cardiomyopathy who was deceased at age 11 mo, we proposed an experimental treatment combining the use of synthetic ketone bodies (D,L-3-OH butyrate) as an alternative energy source, 2:1 ketogenic diet to reduce glucose intake and high-protein diet to enhance gluconeogenesis. Twentyfour months after the onset of this treatment, echocardiography showed an improvement of cardiomyopathy. Growth and liver size remained normal, and no side effects were observed. Blood glucose levels remained within the normal range and insulin levels decreased. These findings show that synthetic ketone bodies as well as lowcarbohydrate, high-lipid, and high-protein diet may be a more beneficial therapeutic choice therapeutic choice for GSD III patients with cardiomyopathy. These encouraging data need to be confirmed in more GSD III patients presenting with cardiac or muscular symptoms. (Pediatr Res 70: 638-641, 2011)

BackgroundThe principal aim of this study was to investigate the long-term outcomes of a large cohort of patients with ornithine transcarbamylase deficiency (OTCD) who were followed up at a single medical center.MethodsWe analyzed clinical, biochemical and genetic parameters of 90 patients (84 families, 48 males and 42 females) with OTCD between 1971 and 2011.ResultsTwenty-seven patients (22 boys, 5 girls) had a neonatal presentation; 52 patients had an “intermediate” late-onset form of the disease (21 boys, 31 girls) that was revealed between 1 month and 16 years; and 11 patients (5 boys, 6 girls) presented in adulthood (16 to 55 years). Patients with a neonatal presentation had increased mortality (90% versus 13% in late-onset forms) and peak plasma ammonium (mean value: 960 μmol/L versus 500 μmol/L) and glutamine (mean value: 4110 μmol/L versus 1000 μmol/L) levels at diagnosis. All of the neonatal forms displayed a greater number of acute decompensations (mean value: 6.2/patient versus 2.5 and 1.4 in infants and adults, respectively). In the adult group, some patients even recently died at the time of presentation during their first episode of coma. Molecular analyses identified a deleterious mutation in 59/68 patients investigated. Single base substitutions were detected more frequently than deletions (69% and 12%, respectively), with a recurrent mutation identified in the late-onset groups (pArg40 His; 13% in infants, 57% in adults); inherited mutations represented half of the cases. The neurological score did not differ significantly between the patients who were alive in the neonatal or late-onset groups and did not correlate with the peak ammonia and plasma glutamine concentrations at diagnosis. However, in late-onset forms of the disease, ammonia levels adjusted according to the glutamine/citrulline ratio at diagnosis were borderline predictors of low IQ (p = 0.12 by logistic regression; area under the receiver operating characteristic curve of 76%, p <0.05).ConclusionsOTCD remains a severe disease, even in adult-onset patients for whom the prevention of metabolic decompensations is crucial. The combination of biochemical markers warrants further investigations to provide additional prognostic information regarding the neurological outcomes of patients with OTCD.

BackgroundLysinuric protein intolerance (LPI) is a rare metabolic disease resulting from recessive-inherited mutations in the SLC7A7 gene encoding the cationic amino-acids transporter subunit y+LAT1. The disease is characterised by protein-rich food intolerance with secondary urea cycle disorder, but symptoms are heterogeneous ranging from infiltrative lung disease, kidney failure to auto-immune complications. This retrospective study of all cases treated at Necker Hospital (Paris, France) since 1977 describes LPI in both children and adults in order to improve therapeutic management.ResultsSixteen patients diagnosed with LPI (12 males, 4 females, from 9 families) were followed for a mean of 11.4 years (min-max: 0.4-37.0 years). Presenting signs were failure to thrive (n = 9), gastrointestinal disorders (n = 2), cytopenia (n = 6), hyperammonemia (n = 10) with acute encephalopathy (n = 4) or developmental disability (n = 3), and proteinuria (n = 1). During follow-up, 5 patients presented with acute hyperammonemia, and 8 presented with developmental disability. Kidney disease was observed in all patients: tubulopathy (11/11), proteinuria (4/16) and kidney failure (7/16), which was more common in older patients (mean age of onset 17.7 years, standard deviation 5.33 years), with heterogeneous patterns including a lupus nephritis. We noticed a case of myocardial infarction in a 34-year-old adult. Failure to thrive and signs of haemophagocytic-lymphohistiocytosis were almost constant. Recurrent acute pancreatitis occurred in 2 patients. Ten patients developed an early lung disease. Six died at the mean age of 4 years from pulmonary alveolar proteinosis. This pulmonary involvement was significantly associated with death. Age-adjusted plasma lysine concentrations at diagnosis showed a trend toward increased values in patients with a severe disease course and premature death (Wilcoxon p = 0.08; logrank, p = 0.17). Age at diagnosis was a borderline predictor of overall survival (logrank, p = 0.16).ConclusionsAs expected, early pulmonary involvement with alveolar proteinosis is frequent and severe, being associated with an increased risk of death. Kidney disease frequently occurs in older patients. Cardiovascular and pancreatic involvement has expanded the scope of complications. A borderline association between increased levels of plasma lysine and poorer outome is suggested. Greater efforts at prevention are warranted to optimise the long-term management in these patients.