Cross-sectional observational study of 208 patients with non-classical urea cycle disorders.

Urea cycle disorders (UCDs) are inherited disorders of ammonia detoxification often regarded as mainly of relevance to pediatricians. Based on an increasing number of case studies it has become obvious that a significant number of UCD patients are affected by their disease in a non-classical way: presenting outside the newborn period, following a mild course, presenting with unusual clinical features, or asymptomatic patients with only biochemical signs of a UCD. These patients are surviving into adolescence and adulthood, rendering this group of diseases clinically relevant to adult physicians as well as pediatricians. In preparation for an international workshop we collected data on all patients with non-classical UCDs treated by the participants in 20 European metabolic centres. Information was collected on a cohort of 208 patients 50% of which were ≥ 16 years old. The largest subgroup (121 patients) had X-linked ornithine transcarbamylase deficiency (OTCD) of whom 83 were female and 29% of these were asymptomatic. In index patients, there was a mean delay from first symptoms to diagnosis of 1.6 years. Cognitive impairment was present in 36% of all patients including female OTCD patients (in 31%) and those 41 patients identified presymptomatically following positive newborn screening (in 12%). In conclusion, UCD patients with non-classical clinical presentations require the interest and care of adult physicians and have a high risk of neurological complications. To improve the outcome of UCDs, a greater awareness by health professionals of the importance of hyperammonemia and UCDs, and ultimately avoidance of the still long delay to correctly diagnose the patients, is crucial.

Establishing a consortium for the study of rare diseases: The Urea Cycle Disorders Consortium.

The Urea Cycle Disorders Consortium (UCDC) was created as part of a larger network established by the National Institutes of Health to study rare diseases. This paper reviews the UCDC's accomplishments over the first 6years, including how the Consortium was developed and organized, clinical research studies initiated, and the importance of creating partnerships with patient advocacy groups, philanthropic foundations and biotech and pharmaceutical companies.

Switch from Sodium Phenylbutyrate to Glycerol Phenylbutyrate Improved Metabolic Stability in an Adolescent with Ornithine Transcarbamylase Deficiency.

A male patient, born in 1999, was diagnosed with ornithine transcarbamylase deficiency as neonate and was managed with a strict low-protein diet supplemented with essential amino acids, L-citrulline, and L-arginine as well as sodium benzoate. He had an extensive history of hospitalizations for hyperammonemic crises throughout childhood and early adolescence, which continued after the addition of sodium phenylbutyrate in 2009. In December 2013 he was switched to glycerol phenylbutyrate, and his metabolic stability was greatly improved over the following 7 months prior to liver transplant.

Frequency and Pathophysiology of Acute Liver Failure in Ornithine Transcarbamylase Deficiency (OTCD).

BACKGROUND: Acute liver failure (ALF) has been reported in ornithine transcarbamylase deficiency (OTCD) and other urea cycle disorders (UCD). The frequency of ALF in OTCD is not well-defined and the pathogenesis is not known. AIM: To evaluate the prevalence of ALF in OTCD, we analyzed the Swiss patient cohort. Laboratory data from 37 individuals, 27 females and 10 males, diagnosed between 12/1991 and 03/2015, were reviewed for evidence of ALF. In parallel, we performed cell culture studies using human primary hepatocytes from a single patient treated with ammonium chloride in order to investigate the inhibitory potential of ammonia on hepatic protein synthesis. RESULTS: More than 50% of Swiss patients with OTCD had liver involvement with ALF at least once in the course of disease. Elevated levels of ammonia often correlated with (laboratory) coagulopathy as reflected by increased values for international normalized ratio (INR) and low levels of hepatic coagulation factors which did not respond to vitamin K. In contrast, liver transaminases remained normal in several cases despite massive hyperammonemia and liver involvement as assessed by pathological INR values. In our in vitro studies, treatment of human primary hepatocytes with ammonium chloride for 48 hours resulted in a reduction of albumin synthesis and secretion by approximately 40%. CONCLUSION: In conclusion, ALF is a common complication of OTCD, which may not always lead to severe symptoms and may therefore be underdiagnosed. Cell culture experiments suggest an ammonia-induced inhibition of hepatic protein synthesis, thus providing a possible pathophysiological explanation for hyperammonemia-associated ALF.

Induction of specific immunotherapy with hymenoptera venoms using ultrarush regimen in children: safety and tolerance.

Background & Objective. Ultrarush induction for specific venom immunotherapy has been shown to be reliable and efficacious in adults. In this study its safety and tolerance in children was evaluated. Methods. Retrospective analysis of 102 ultrarush desensitizations carried out between 1997 and 2005 in 94 children, aged 4 to 15 years. Diagnosis and selection for immunotherapy were according to recommendations of the European Academy of Allergy and Clinical Immunology. Systemic adverse reactions (SARs) were described using the classification of H. L. Mueller. Results. All patients reached the cumulative dose of 111.1 µg hymenoptera venom within 210 minutes. Six patients (6%) had allergic reactions grade I; 2 patients (2%) grade II and 5 patients (5%) grade III. Three patients (3%) showed unclassified reactions. SARs did not occur in the 15 patients aged 4 to 8 years and they were significantly more frequent in girls (29%) compared with boys (12%) (P = 0.034, multivariant analysis) and in bee venom extract treated patients (20%) compared to those treated with wasp venom extract (8%) (OR 0.33, 95% Cl 0.07-1.25). Conclusion. Initiation of specific immunotherapy by ultrarush regimen is safe and well tolerated in children and should be considered for treating children with allergy to hymenoptera venom.

Nonpuerperal mastitis in adolescents.

Mastitis in non-lactating adolescents is rare and its cause unclear. This retrospective study summarizes 22 such episodes, in 3 of which Staphylococcus aureus was isolated. Serum prolactin levels were normal. Most patients were successfully treated with oral amoxicillin-clavulanic acid. Three patients with bilateral breast cysts had a recurrence.