Caregiver burden, and parents' perception of disease severity determine health-related quality of life in paediatric patients with intoxication-type inborn errors of metabolism.

Background: Living with a non-acute (phenylketonuria) or acute (e.g. urea cycle disorders, organic acidurias) intoxication-type inborn error of metabolism (IT-IEM) can have a substantial impact on health-related quality of life (HrQoL) of paediatric patients and their families. Parents take primary responsibility for treatment monitoring and experience worry and fear about their child's health status. Quantitative evidence on parental psychological factors which may influence the HrQoL of patients with IT-IEM are sparse to non-existent. Methods: In this multicenter survey study 50 parents of IT-IEM patients (ages 5-19) assessed the severity of their child's disease, reported on caregiver burden, and proxy-rated their child's HrQoL. Additionally, 35 patient self-reports on HrQoL were obtained (n = 16 female patients, n = 19 male patients). Multiple linear regressions were conducted to examine the predictive power of child age, sex, medical diagnosis type (acute / non-acute), parental perceived disease severity and caregiver burden on patients' HrQoL. Mediation analyses were used to investigate the relation of caregiver burden and parental ratings of disease severity with patients' HrQoL. Results: Significant regression models for self-reported [F(5,34) = 10.752, p < .001, R 2 adj.. = 0.59] and parent proxy reported HrQoL [F(5,49) = 20.513, p < .001, R 2 adj.. = 0.67] emerged. High caregiver burden and perceived disease severity predicted significantly lower patient self- and proxy-reported HrQoL while type of diagnosis (acute versus non-acute) did not. Female sex predicted significantly lower self-reported HrQoL. High caregiver burden was the mediating factor between high perceived severity of the child's disease and lower proxy- by parent rated HrQoL. Conclusion: Detecting elevated burden of care and providing support for parents seems crucial to prevent adverse consequences for their children's HrQoL. Intervention studies are needed, to assess which support programs are most efficient.

Successful heart transplantation in a patient with adolescent-onset dilated cardiomyopathy secondary to propionic acidaemia: a case report.

Background: Propionic acidaemia (PA) is an autosomal recessive disorder resulting from deficiency of propionyl-CoA carboxylase, a mitochondrial enzyme that metabolizes propionyl-CoA. Generally, patients with PA develop symptoms in the neonatal period due to protein intake through breastfeeding; however, late-onset PA with atypical symptoms, including cardiomyopathy, has been recently reported. Case summary: We present the case of a 25-year-old male with late-onset PA complicated by advanced heart failure (HF) due to isolated secondary dilated cardiomyopathy, who required left ventricular assist device (LVAD) implantation and finally underwent heart transplantation (HTx). Initially, the patient developed HF at the age of 16 and was diagnosed with mitochondrial cardiomyopathy. Due to refractory HF, he underwent an LVAD implantation and was scheduled for HTx. During the preoperative period for HTx, the patient suffered from sepsis due to the worsening of LVAD driveline exit-site infection complicated by overt metabolic acidosis, finally leading to the diagnosis of late-onset PA. After this diagnosis, adequate nutritional interventions were introduced, and the cardiac function was partially restored enough for him to be weaned-off LVAD; however, the patient became inotrope dependent and underwent HTx. The post-HTx course was uneventful with special nutritional management, and he has experienced no adverse metabolic events in the past 3 years. Discussion: Late-onset PA can cause isolated adult-onset cardiomyopathy, and LVAD or HTx should be considered when PA is complicated by advanced HF and is unresponsive to conventional medical therapies.

SARS-CoV-2 infection in a patient with propionic acidemia.

We describe a 14-month-old boy, with a previous diagnosis of propionic acidemia (PA) by expanded newborn screening, who, admitted for a suspected metabolic crisis, tested positive for SARS-CoV-2. Since propionic acidemia was diagnosed, the patient has followed the recommended diet for this inborn error of metabolism. Although propionic acidemia patients are at a high risk of suffering metabolic crises, frequently associated with permanent clinical complications, psychomotor development of this patient was normal. The SARS-CoV-2 infection (at about 1 year of age) caused the patient's first metabolic crisis. However, his clinical course was in keeping with a mild clinical form of COVID-19, and he recovered without experiencing severe clinical consequences. We describe this patient in order to improve the knowledge about follow up of PA patients identified by newborn screening and to increase the limited number of reports of SARS-CoV-2 infection in children with comorbidities, especially inborn errors of metabolism.

Acidemia propiónica: una causa sumamente rara de linfohistiocitosis hemofagocítica en un lactante / Propionic acidemia: an extremely rare cause of hemophagocytic lymphohistiocytosis in an infant

La linfohistiocitosis hemofagocítica (LHH) puede ser primaria (hereditaria) o secundaria a infecciones, tumores malignos, trastornos reumatológicos, síndromes de inmunodeficiencia y metabolopatías. Se informaron casos de intolerancia a la proteína lisinúrica, deficiencia de múltiples sulfatasas, galactosemia, enfermedad de Gaucher, síndrome de Pearson y galactosialidosis. No se sabe cómo se desencadena la LHH en las metabolopatías. Se diagnosticó LHH en un lactante de 2 meses con letargo, palidez, alimentación deficiente, hepatoesplenomegalia, fiebre y pancitopenia, y se instauró el protocolo HLH-2004. Se realizaron, en conjunto, análisis para detectar mutaciones genéticas y pruebas metabólicas; los resultados fueron negativos para las mutaciones genéticas de LHH primaria, pero se detectaron hiperamoniemia y concentración elevada de metilcitrato. Se diagnosticó acidemia propiónica. Aquí informamos sobre un caso de LHH secundaria a acidemia propiónica. Es posible la realización simultánea de pruebas de detección de trastornos metabólicos y de mutaciones genéticas para el diagnóstico temprano en los lactantes con LHH

Hemophagocytic lymphohystiocytosis (HLH) may be primary (inherited/familial) or secondary to infections, malignancies, rheumatologic disorders, immune deficiency syndromes and metabolic diseases. Cases including lysinuric protein intolerance, multiple sulfatase deficiency, galactosemia, Gaucher disease, Pearson syndrome, and galactosialidosis have previously been reported. It is unclear how the metabolites trigger HLH in metabolic diseases. A 2-month-old infant with lethargy, pallor, poor feeding, hepatosplenomegaly, fever and pancytopenia, was diagnosed with HLH and the HLH-2004 treatment protocol was initiated. Analysis for primary HLH gene mutations and metabolic screening tests were performed together; primary HLH gene mutations were negative, but hyperammonemia and elevated methyl citrate were detected. Propionic acidemia was diagnosed with tandem mass spectrometry in neonatal dried blood spot. We report this case of HLH secondary to propionic acidemia. Both metabolic disorder screening tests and gene mutation analysis may be performed simultaneously especially for early diagnosis in infants presenting with HLH.

Combinations of exonic deletions and rare mutations lead to misdiagnosis of propionic acidemia.

Propionic acidemia (PA) is an inborn metabolic error characterized by the accumulation of propionic acid due to deficiency of propionyl-CoA carboxylase (PCC). In this study, we present an intractable case with PCC activity defects. Although next-generation sequencing was applied twice to test genetic defects of the patients, no pathogenic mutations of a metabolic disease gene were identified. Mutations related to the disease were screened in prenatal diagnosis, but the mother still gave birth to an unhealthy neonate. We analyzed the second sequencing data and found that a novel synonymous PCCA mutation c.1746 G>C (p.S582S), which leads to an exon 19 skip, was screened out. Furthermore, a deletion mutation covering exon 3 and exon 4 of the PCCA gene was identified using q-PCR and DNA breakpoint test. Both of these can result in the loss of PCCA protein function. The finding expands the mutation spectrum of the PCCA gene and indicates that another technology such as cDNA analysis, multiplex ligation-dependent probe amplification (MLPA), or long-read whole-genome sequencing should be considered to improve the detection rates of special cases.

A Novel PCCA Mutation in a Patient With Late-Onset Propionic Acidemia Identified by Genetic Diagnosis Panel.

Background: Propionic acidemia (PA) is an extremely rare autosomal recessive disorder which is caused by the deficiency of propionyl-CoA carboxylase (PCC) and associated with pathogenic variants in PCCA or PCCB gene. Case Report: Detection of PA in neonates is possible using Propionyl carnitine (C3) analysis by tandem mass spectrometry (MS/MS) in dried blood spots (DBS). Here we report one patient with PA. C3 in this case was normal in the initial screening and recall check and only manifested as the slightly increase of C3/C2, 3-hydroxypropionate in urine was only slightly elevated. Then two pathogenic mutations (c.802C>T/c.827delG) were detected in the PCCA gene by Genetic diagnosis panel. Among them, the variation rs774738181 (c.802C>T) was present on the dbSNP database which appeared to be "Likely pathogenic" in GenBank dbSNP (100915068). c.827delG was a novel frameshift mutation, leading to p.Gly276ValfsX46 mutation of amino acid sequence in PCCA. The patient underwent 1 year of follow-up, had total of 7 times and remain asymptomatic whose blood ammonia and liver function were normal. When the child was 1 year of age (in May of 2017), C3 and 3-Hydroxypropionate sudden elevated significantly, that proved pathogenicity of c.802C>T and c.827delG. Conclusion: Two novel mutations (c. 802C>T and c.827delG) in PCCA gene may be associated with late-onset PA, expanding its mutational spectrum. Maybe there is relation between the severity of propionyl-CoA carboxylase (PCC) activity defects and different genotypes.

Long QT syndrome diagnosed in two sisters with propionic acidemia: a case report.

Propionic acidemia (PA) is a rare autosomal recessive metabolic disorder caused by deficiency of the mitochondrial enzyme propionyl-CoA carboxylase (PCC). This disorder mostly progresses with episodes of metabolic acidosis. Cardiomyopathy is among the cardiac complications known to occur during metabolic decompensation episodes. However, several recent papers emphasized the association of PA and long QT syndrome (LQTS) which may lead to extremely serious and fatal consequences. In this report, we describe two sisters with PA who have prolonged QT duration that were incidentally detected in an outpatient setting. LQTS was verified by electrocardiogram, stress test and 24 h rhythm holter monitoring. By this report, we want to emphasize the importance of early diagnosis of LQTS in asymptomatic patients with PA to prevent fatal complications.

Veno-Venous Extracorporeal Membrane Oxygenation for Continuous Renal Replacement in a Neonate with Propionic Acidemia.

The usual indications for extra corporeal membrane oxygenation (ECMO) are for respiratory or cardiac failure. Although continuous renal replacement therapy (CRRT) is frequently used when patients are on ECMO, the need for CRRT as the primary indication for ECMO is rare. A case of a neonate placed onto veno-venous ECMO for the use of CRRT to treat hyperammonemia from propionic acidemia is presented.

Propionic acidemia: diagnosis and neuroimaging findings of this neurometabolic disorder.

OBJECTIVE: Propionic acidemia is one of the rare congenital neurometabolic disorders with autosomal recessive inheritance. This disorder is caused by a defect in the propionyl-CoA carboxylase enzyme and can be presented with life-threatening ketoacidosis, lethargy, failure to thrive, and developmental delay. MATERIALS & METHODS: The patients diagnosed as having propionic acidemia in Neurology Department of Mofid Children's Hospital in Tehran, Iran, between 2002 and 2012 were include in our study. This disorder was confirmed by clinical manifestations, neuroimaging findings, and neurometabolic assessment in the reference laboratory in Germany. Our study was conducted to define the sex, age, gender, past medical history, developmental status, clinical findings, and neuroimaging manifestations in 10 patients with propionic acidemia. RESULTS: Seventy percent of patients were offspring of consanguineous marriages. In this study, only one patient had microcephaly at birth, but at detection time, 30% of patients had head circumference and weight below the 3rd percentile. The patients were followed for approximately 5 years and this follow-up showed that the patients with early diagnosis had a more favorable clinical response. Neuroimaging findings included brain atrophy, white matter and globus pallidus involvement. CONCLUSION: Finally we suggest that early diagnosis and treatment have an important role in the prevention of disease progression.