Acute intoxication‐type inborn errors of metabolism (IT‐IEM) such as urea cycle disorders and non‐acute IT‐IEM such as phenylketonuria have a major impact on paediatric patients' life. Patients have to adhere to a strict diet but may face neurocognitive impairment and – in acute diseases – metabolic decompensations nevertheless. Research on the subjective burden of IT‐IEM remains sparse. Studies with appropriate sample sizes are needed to make valid statements about health‐related quality of life (HrQoL) in children and adolescents with IT‐IEM. Six international metabolic centres contributed self‐reports and proxy reports of HrQoL (assessed with the Paediatric Quality of Life Inventory) to the final data set (n = 251 patients; age range 2.3‐18.8 years). To compare HrQoL of the patient sample with norm data and between acute and non‐acute IT‐IEM, t tests were conducted. To examine the influence of child age, sex, diagnosis and current dietary treatment on HrQoL, multiple linear regression analyses were conducted. Self‐reports and proxy reporst showed significantly lower HrQoL total scores for children with IT‐IEM compared to healthy children. Current dietary treatment significantly predicted lower proxy reported total HrQoL. Children with non‐acute IT‐IEM reported significantly lower psychosocial health and emotional functioning than children with acute IT‐IEM. The patient sample showed significantly impaired HrQoL and a diet regimen remains a risk factor for lower HrQoL. Differences in HrQoL between acute and non‐acute IT‐IEM subgroups indicate that factors beyond symptom severity determine the perception of disease burden. Identifying these factors is of crucial importance to develop and implement appropriate interventions for those in need.

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Background The main genetic causes of homocystinuria are cystathionine beta-synthase (CBS) deficiency and the remethylation defects. Many patients present in childhood but milder forms may present later in life. Some countries have newborn screening programs for the homocystinurias but these do not detect all patients. Results HCU Network Australia is one of the very few support groups for patients with homocystinurias. Here we report the results of its survey of 143 patients and caregivers from 22 countries, evaluating current diagnostic pathways and management for the homocystinurias. Most (110) of the responses related to patients with CBS deficiency. The diagnosis was made by newborn screening in 20% of patients and in 50% of the others within 1 year of the initial symptom but in 12.5% it took over 15 years. The delay was attributed mainly to ignorance of the disease. Physicians need to learn to measure homocysteine concentrations in children with neurodevelopmental problems, and in patients with heterogeneous symptoms such as thromboembolism, dislocation of the optic lens, haemolytic uraemic syndrome, and psychiatric disease. Even when the diagnosis is made, the way it is communicated is sometimes poor. Early-onset CBS deficiency usually requires a low-protein diet with amino acid supplements. More than a third of the participants reported problems with the availability or cost of treatment. Only half of the patients always took their amino acid mixture. In contrast, good adherence to the protein restriction was reported in 98% but 80% said it was hard, time-consuming and caused unhappiness. Conclusions There is often a long delay in diagnosing the homocystinurias unless this is achieved by newborn screening; this survey also highlights problems with the availability and cost of treatment and the palatability of protein substitutes.