A Methionine-Portioning-Based Medical Nutrition Therapy with Relaxed Fruit and Vegetable Consumption in Patients with Pyridoxine-Nonresponsive Cystathionine-ß-Synthase Deficiency.

The main treatment for pyridoxine-nonresponsive cystathionine-ß-synthase deficiency is a strict diet. Most centers prescribe low-protein diets based on gram-protein exchanges, and all protein sources are weighed. The purpose of this study is to investigate the effects of a more liberal methionine (Met)-based diet with relaxed consumption of fruits and vegetables on metabolic outcomes and dietary adherence. Ten patients previously on a low-protein diet based on a gram-protein exchange list were enrolled. The natural protein exchange lists were switched to a "Met portion exchange list". Foods containing less than 0.005 g methionine per 100 g of the food were accepted as exchange-free foods. The switch to Met portioning had no adverse effects on the control of plasma homocysteine levels in terms of metabolic outcomes. It resulted in a significant reduction in patients' daily betaine dose. All patients preferred to continue with this modality. In conclusion, methionine-portion-based medical nutrition therapy with relaxed consumption of fruits and vegetables seems to be a good and safe option to achieve good metabolic outcomes and high treatment adherence.

Safety of COVID-19 vaccines in children with inborn errors of metabolism in terms of developing metabolic decompensation.

AIM: There are no recommended guidelines or clinical studies on safety of COVID-19 vaccines in patients with inborn errors of metabolism (IEMs). Here, we aimed to examine the relationship between COVID-19 vaccination and metabolic outcome in paediatric IEM patients. METHODS: Patients with IEM between the ages of 12 and 18 were enrolled. Term metabolic decompensation was defined as acute disruption in metabolic homeostasis due to vaccination. Clinical and biochemical markers were compared between pre- and post-vaccination periods. RESULTS: Data from a total of 36 vaccination episodes in 18 patients were included. Thirteen patients had intoxication-type metabolic disorders including organic acidemia (OA), urea cycle disorders (UCDs), maple syrup urine disease (MSUD) and phenylketonuria (PKU); 4 patients had energy metabolism disorders including fatty acid metabolism disorders and LIPIN 1 deficiency; and 1 patient had glycogen storage disorder (GSD) type 5. Seventeen patients received BNT162b2, and 1 received CoronaVac because of an underlying long QT syndrome. Fatty acid metabolism disorders, LIPIN 1 deficiency and GSD type 5 were included in the same group named 'metabolic myopathies'. In two PKU patients, plasma phenylalanine level increased significantly within 24 h following the second dose of vaccination. None of the OA, UCD, MSUD and metabolic myopathy patients experienced acute metabolic attack and had emergency department admission due to metabolic decompensation within 1 month after vaccination. CONCLUSIONS: COVID-19 vaccines did not cause acute metabolic decompensation in a cohort of 18 children with IEM.