Distinct Clinical Courses and Shortened Lifespans in Childhood-Onset DNA Polymerase Gamma Deficiency.

Background and Objectives: DNA polymerase subunit gamma (POLG) deficiency is likely the most frequent cause of nuclear-encoded mitochondrial disorders. POLG-related disorders reportedly constitute a spectrum of overlapping phenotypes from infancy to late adulthood. We retrospectively reviewed natural histories for 40 children carrying biallelic pathogenic POLG variants. Methods: The patients were identified by the French coordinating center for mitochondrial disorders (CARAMMEL), making this a large monocentric series on childhood-onset POLG deficiency. Results: Three patterns of clinical course and survival were observed, distinguished by main category of symptoms: neurologic, hepatic, and gastrointestinal. A total of 24 patients needed urgent neurointensive care for tonic-clonic seizures, myoclonic epilepsy, and status epilepticus, occasionally precipitated by valproate administration. Other neurologic symptoms included dystonia, cerebellar ataxia, and peripheral neuropathy. We report 6 POLG-deficient patients with polyradiculoneuropathy mimicking subacute Guillain-Barré syndrome and provide postgadolinium MRI evidence of diffuse cranial nerve root and cauda equina enhancement, suggesting these disorders have an inflammatory component. Children presenting with enteral nervous system involvement had vomiting, gastroparesis, and chronic intestinal pseudo-obstruction. They had later ages of onset and lived much longer. Primarily, hepatic presentations had the earliest onset and shortest survivals. Secondary hepatic failure was frequently precipitated by valproate administration given before diagnosis to patients with focal impaired awareness seizures or absence of seizures. These POLG deficiencies were often fatal, with age at death ranging from 3 months to 10 years, with a significant difference in survival between the 3 clinical forms; 6 of the 40 children did survive. No genotype-phenotype correlations were found for the 3 clinical course types. Discussion: The study demonstrates the prevalence of neurologic presentation and the extent of central, peripheral, and autonomous nervous system involvement in 60% of patients. Most of the patients with early onset and rapidly fatal hepatic failure did not live long enough to develop neurologic symptoms. The study revealed a new clinical form of POLG deficiency presenting with neurodigestive symptoms with longer lifespan. We also propose that POLG deficiency should be considered in children presenting with unexplained polyradiculoneuropathy, demyelinating neuropathy, and elevated CSF protein. Finally, valproate administration remains a notable cause of avoidable death in POLG-deficient patients.

Cognitive impairment in children and adults with cerebrotendinous xanthomatosis: A French cohort study.

Cerebrotendinous xanthomatosis is a rare and treatable metabolic disorder related to the accumulation of cholestanol. This disorder is primarily associated with motor and cognitive impairments, although the latter has not been extensively characterized. The objectives of this work were to define the cognitive profile found in cerebrotendinous xanthomatosis patients, investigate the progression of cognitive impairment over time, and search for radio-clinical correlations. Through a multicentric chart review study, we collected cognitive and radiological data from nine children and eighteen adults with genetically proven cerebrotendinous xanthomatosis. We performed a volumetric and morphological analysis of the brain magnetic resonance imaging. In our cohort, 44% (4/9) of children and 78% (14/18) of adults exhibited cognitive impairment that can be severe. The study revealed a significant impairment in various cognitive domains, specifically executive, attentional, language, and visuo-spatial. Among adults, 16% (3/18) developed dementia after age 50. These three patients had delayed chenodeoxycholic acid treatment and important cerebral atrophy. Besides these three cases of late-onset cognitive decline, Mini-Mental State Evaluation was generally stable, suggesting cognitive impairment due to a neurodevelopmental disorder and persisting in adulthood. Cognitive impairment was less common in children, possibly related to early chenodeoxycholic acid treatment in our cohort. The severity of magnetic resonance imaging abnormalities did not predict cognitive impairment in patients. Overall, in cerebrotendinous xanthomatosis, cognitive impairment can be severe and mainly neurodevelopmental. Early chenodeoxycholic acid treatment might be associated with a reduced risk of cognitive decline.

Late-onset refractory hemolytic anemia in siblings treated for methionine synthase reductase deficiency: A rare complication possibly prevented by hydroxocobalamin dose escalation?

Methionine synthase reductase deficiency (cblE) is a rare autosomal recessive inborn error of cobalamin metabolism caused by pathogenic variants in the methionine synthase reductase gene (MTRR). Patients usually exhibit early-onset bone marrow failure with pancytopenia including megaloblastic anemia. The latter can remain isolated or patients may present developmental delay and rarely macular dysfunction. Treatment mostly includes parenteral hydroxocobalamin to maximize the residual enzyme function and betaine to increase methionine concentrations and decrease homocysteine accumulation. We report herein 2 cblE siblings diagnosed in the neonatal period with isolated pancytopenia who, despite treatment, exhibited in adulthood hemolytic anemia (LDH >11 000 U/L, undetectable haptoglobin, elevated unconjugated bilirubin) which could finally be successfully treated by hydroxocobalamin dose escalation. There was no obvious trigger apart from a parvovirus B19 infection in one of the patients. This is the first report of such complications in adulthood. The use of LDH for disease monitoring could possibly be an additional useful biomarker to adjust hydroxocobalamin dosage. Bone marrow infection with parvovirus B19 can complicate this genetic disease with erythroblastopenia even in the absence of an immunocompromised status, as in other congenital hemolytic anemias. The observation of novel hemolytic features in this rare disease should raise awareness about specific complications in remethylation disorders and plea for hydroxocobalamin dose escalation.

Management of seizures in patients with primary mitochondrial diseases: consensus statement from the InterERNs Mitochondrial Working Group.

BACKGROUND AND PURPOSE: Primary mitochondrial diseases (PMDs) are common inborn errors of energy metabolism, with an estimated prevalence of one in 4300. These disorders typically affect tissues with high energy requirements, including heart, muscle and brain. Epilepsy may be the presenting feature of PMD, can be difficult to treat and often represents a poor prognostic feature. The aim of this study was to develop guidelines and consensus recommendations on safe medication use and seizure management in mitochondrial epilepsy. METHODS: A panel of 24 experts in mitochondrial medicine, pharmacology and epilepsy management of adults and/or children and two patient representatives from seven countries was established. Experts were members of five different European Reference Networks, known as the Mito InterERN Working Group. A Delphi technique was used to allow the panellists to consider draft recommendations on safe medication use and seizure management in mitochondrial epilepsy, using two rounds with predetermined levels of agreement. RESULTS: A high level of consensus was reached regarding the safety of 14 out of all 25 drugs reviewed, resulting in endorsement of National Institute for Health and Care Excellence guidelines for seizure management, with some modifications. Exceptions including valproic acid in POLG disease, vigabatrin in patients with γ-aminobutyric acid transaminase deficiency and topiramate in patients at risk for renal tubular acidosis were highlighted. CONCLUSIONS: These consensus recommendations describe our intent to improve seizure control and reduce the risk of drug-related adverse events in individuals living with PMD-related epilepsy.

Clinical, Neuroimaging, and Metabolic Footprint of the Neurodevelopmental Disorder Caused by Monoallelic HK1 Variants.

Background and Objectives: Hexokinase 1 (encoded by HK1) catalyzes the first step of glycolysis, the adenosine triphosphate-dependent phosphorylation of glucose to glucose-6-phosphate. Monoallelic HK1 variants causing a neurodevelopmental disorder (NDD) have been reported in 12 individuals. Methods: We investigated clinical phenotypes, brain MRIs, and the CSF of 15 previously unpublished individuals with monoallelic HK1 variants and an NDD phenotype. Results: All individuals had recurrent variants likely causing gain-of-function, representing mutational hot spots. Eight individuals (c.1370C>T) had a developmental and epileptic encephalopathy with infantile onset and virtually no development. Of the other 7 individuals (n = 6: c.1334C>T; n = 1: c.1240G>A), 3 adults showed a biphasic course of disease with a mild static encephalopathy since early childhood and an unanticipated progressive deterioration with, e.g., movement disorder, psychiatric disease, and stroke-like episodes, epilepsy, starting in adulthood. Individuals who clinically presented in the first months of life had (near)-normal initial neuroimaging and severe cerebral atrophy during follow-up. In older children and adults, we noted progressive involvement of basal ganglia including Leigh-like MRI patterns and cerebellar atrophy, with remarkable intraindividual variability. The CSF glucose and the CSF/blood glucose ratio were below the 5th percentile of normal in almost all CSF samples, while blood glucose was unremarkable. This biomarker profile resembles glucose transporter type 1 deficiency syndrome; however, in HK1-related NDD, CSF lactate was significantly increased in all patients resulting in a substantially different biomarker profile. Discussion: Genotype-phenotype correlations appear to exist for HK1 variants and can aid in counseling. A CSF biomarker profile with low glucose, low CSF/blood glucose, and high CSF lactate may point toward monoallelic HK1 variants causing an NDD. This can help in variant interpretation and may aid in understanding the pathomechanism. We hypothesize that progressive intoxication and/or ongoing energy deficiency lead to the clinical phenotypes and progressive neuroimaging findings.

Vitamin deficiencies in children: Lessons from clinical and neuroimaging findings.

BACKGROUND AND AIMS: Water-soluble vitamins play an essential coenzyme role in the nervous system. Acquired vitamin deficiencies are easily treatable, however, without treatment, they can lead to irreversible complications. This study aimed to provide clinical, laboratory parameters and neuroimaging data on vitamin deficiencies in an attempt to facilitate early diagnosis and prompt supplementation. METHODS: From July 1998 to July 2023, patients at Necker-Enfants-Malades Hospital presenting with acute neurological symptoms attributed to acquired vitamin deficiency were included. Clinical data were extracted from Dr Warehouse database. Neuroimaging, biochemical and electrophysiological data were reviewed. RESULTS: Patients with vitamin B1 deficiency exhibited abnormal eye movements (n = 4/4), fluctuations in consciousness (n = 3/4), and ataxia (n = 3/4). Brain MRI showed alterations of fourth ventricle region (n = 4/4), periaqueductal region (n = 4/4), tectum (n = 3/4), and median thalami (n = 3/4). Patients with vitamin B2 deficiency presented with early onset hypotonia (n = 3/4), hyperlactatemia (n = 4/4), and hyperammonemia (n = 4/4). Plasma acylcarnitines revealed a multiple acyl-coA dehydrogenase deficiency-like profile (n = 4/4). In vitamin B12 deficiency, young children presented with developmental delay (n = 7/7) and older children with proprioceptive ataxia (n = 3/3). Brain MRI revealed atrophy (n = 7/7) and spinal MRI hyperintensity in posterior cervical columns (n = 3/3). Metabolic findings showed elevated methylmalonic acid (n = 6/7) and hyperhomocysteinemia (n = 6/7). Patients with vitamin C deficiency exhibited gait disturbances and muscle weakness (n = 2/2). CONCLUSIONS: Acquired vitamin deficiencies may display reversible clinical symptoms mimicking inherited metabolic disorders. Some situations raise suspicion for diagnosis: concordant clinical presentation, suggestive neuroimaging findings, and/or biochemical evidence. Any acute neurological condition should be treated without waiting for definitive biochemical confirmation.

Recurrent "outsider" intronic variation in the SLC5A6 gene causes severe mixed axonal and demyelinating neuropathy, cyclic vomiting and optic atrophy in 3 families from Maghreb.

Sodium dependent multivitamin transporter (SMVT) deficiency is a very rare autosomal recessive disorder characterized by multisystemic clinical manifestations due to combined biotin, panthotenic acid and lipoic acid deficiency. About 10 families have been described so far. Accurate diagnosis is crucial because of the possibility of a supplementation treatment with proven efficacy. Here we describe 4 new patients (3 additional families) originating from the same world region (Algeria, Maghreb). All patients, born form consanguineous parents, were homozygous carriers of the same intronic variation, outside of canonical sites, in the SLC5A6 gene encoding SMVT. RNA study in one family allowed confirming the pathogenic effect of the variation and re-classifying this variant of uncertain significance as pathogenic, opening the possibility of genetic counseling and treatment. The identification of the same variation in three distinct and apparently unrelated families is suggestive of a founder effect. The phenotype of all patients was very similar, with systematic optic atrophy (initially considered as a very rare sign), severe cyclic vomiting, and rapidly progressive mixed axonal and demyelinating sensory motor neuropathy.

Successful treatment of severe MSUD in Bckdhb-/- mice with neonatal AAV gene therapy.

Maple syrup urine disease (MSUD) is rare autosomal recessive metabolic disorder caused by the dysfunction of the mitochondrial branched-chain 2-ketoacid dehydrogenase (BCKD) enzyme complex leading to massive accumulation of branched-chain amino acids and 2-keto acids. MSUD management, based on a life-long strict protein restriction with nontoxic amino acids oral supplementation represents an unmet need as it is associated with a poor quality of life, and does not fully protect from acute life-threatening decompensations or long-term neuropsychiatric complications. Orthotopic liver transplantation is a beneficial therapeutic option, which shows that restoration of only a fraction of whole-body BCKD enzyme activity is therapeutic. MSUD is thus an ideal target for gene therapy. We and others have tested AAV gene therapy in mice for two of the three genes involved in MSUD, BCKDHA and DBT. In this study, we developed a similar approach for the third MSUD gene, BCKDHB. We performed the first characterization of a Bckdhb-/- mouse model, which recapitulates the severe human phenotype of MSUD with early-neonatal symptoms leading to death during the first week of life with massive accumulation of MSUD biomarkers. Based on our previous experience in Bckdha-/- mice, we designed a transgene carrying the human BCKDHB gene under the control of a ubiquitous EF1α promoter, encapsidated in an AAV8 capsid. Injection in neonatal Bckdhb-/- mice at 1014 vg/kg achieved long-term rescue of the severe MSUD phenotype of Bckdhb-/- mice. These data further validate the efficacy of gene therapy for MSUD opening perspectives towards clinical translation.

New description of an MRPS2 homozygous patient: Further features to help expend the phenotype.

Mutated mito-ribosomal protein S2 (MRPS2) was already described in only three subjects, two with sensorineural hearing impairment, mild developmental delay, hypoglycemia, lactic acidemia and combined oxidative phosphorylation system deficiency and another, recently, presenting with a less severe phenotype. In order to expand the phenotype, we describe a new MRPS2 homozygous subject who shows particular features which have not yet been reported: initial microcephaly, joint hypermobility and autistic features.

Motor outcomes in patients with infantile and juvenile Pompe disease: Lessons from neurophysiological findings.

In Infantile Onset Pompe Disease (IOPD), enzyme replacement therapy (ERT) may improve survival, cardiac function, and motor development. However, even with early enzyme replacement therapy, some patients experienced poor response to ERT and abnormal motor milestones that could be due to motor neuron involvement. In this long-term retrospective study, we analyzed concomitant clinical motor outcomes and electroneuromyography (ENMG) findings in patients with IOPD and Juvenile Onset Pompe Disease (JOPD). Twenty-nine pediatric patients were included and 20 surviving were analyzed for neuromotor studies: 12 had IOPD (group 1), 4 had JOPD (group 2) and 4 (group 3) received ERT in the first month of age. Motor nerve conduction studies were mostly normal. Needle EMG performed at diagnosis always indicated the existence of myopathy that responded to ERT. Two IOPD patients (group 1) presenting with mixed motor neuropathy and myopathy displayed a poor outcome and never walked. Two patients became non-walkers (one IOPD patient and one patient of group 3) at respectively 9 and 3 years of age. One JOPD patient is about to lose walking ability. This motor deterioration was associated with the development of a motor neuropathy. Patients older than 10 years of age develop a motor neuropathy. Initial or secondary motor neuron involvement seems to be associated with a poor motor outcome showing that ERT may fail to prevent the accumulation of glycogen in motor neuron. Neurophysiological findings are important to assess severity of motor neuron damage in all Pompe pediatric patients and should be systematically performed.

Citrulline in the management of patients with urea cycle disorders.

BACKGROUND: Treatment recommendations for urea cycle disorders (UCDs) include supplementation with amino acids involved in the urea cycle (arginine and/or citrulline, depending on the enzyme deficiency), to maximize ammonia excretion through the urea cycle, but limited data are available regarding the use of citrulline. This study retrospectively reviewed clinical and biological data from patients with UCDs treated with citrulline and/or arginine at a reference center since 1990. The aim was to describe the prescription, impact, and safety of these therapies. Data collection included patient background, treatment details, changes in biochemical parameters (plasma ammonia and amino acids concentrations), decompensations, and patient outcomes. RESULTS: Overall, 79 patients (median age at diagnosis, 0.9 months) received citrulline and/or arginine in combination with a restricted protein diet, most with ornithine transcarbamylase (n = 57, 73%) or carbamoyl phosphate synthetase 1 (n = 15, 19%) deficiencies. Most patients also received ammonium scavengers. Median follow-up was 9.5 years and median exposure to first treatment with arginine + citrulline, citrulline monotherapy, or arginine monotherapy was 5.5, 2.5, or 0.3 years, respectively. During follow-up, arginine or citrulline was administered at least once (as monotherapy or in combination) in the same proportion of patients (86.1%); the overall median duration of exposure was 5.9 years for arginine + citrulline, 3.1 years for citrulline monotherapy, and 0.6 years for arginine monotherapy. The most common switch was from monotherapy to combination therapy (41 of 75 switches, 54.7%). During treatment, mean ammonia concentrations were 35.9 µmol/L with citrulline, 49.8 µmol/L with arginine, and 53.0 µmol/L with arginine + citrulline. Mean plasma arginine concentrations increased significantly from the beginning to the end of citrulline treatment periods (from 67.6 µmol/L to 84.9 µmol/L, P < 0.05). At last evaluation, mean height and weight for age were normal and most patients showed normal or adapted behavior (98.7%) and normal social life (79.0%). Two patients (2.5%) experienced three treatment-related gastrointestinal adverse reactions. CONCLUSIONS: This study underlines the importance of citrulline supplementation, either alone or together with arginine, in the management of patients with UCDs. When a monotherapy is considered, citrulline would be the preferred option in terms of increasing plasma arginine concentrations.

Long-term follow-up of 64 children with classical infantile-onset Pompe disease since 2004: A French real-life observational study.

BACKGROUND: Classical infantile-onset Pompe disease (IOPD) is the most severe form of Pompe disease. Enzyme replacement therapy (ERT) has significantly increased survival but only a few studies have reported long-term outcomes. METHODS: We retrospectively analyzed the outcomes of classical IOPD patients diagnosed in France between 2004 and 2020. RESULTS: Sixty-four patients were identified. At diagnosis (median age 4 months) all patients had cardiomyopathy and most had severe hypotonia (57 of 62 patients, 92%). ERT was initiated in 50 (78%) patients and stopped later due to being ineffective in 10 (21%). Thirty-seven (58%) patients died during follow-up, including all untreated and discontinued ERT patients, and 13 additional patients. Mortality was higher during the first 3 years of life and after the age of 12 years. Persistence of cardiomyopathy during follow-up and/or the presence of heart failure were highly associated with an increased risk of death. In contrast, cross-reactive immunologic material (CRIM)-negative status (n = 16, 26%) was unrelated to increased mortality, presumably because immunomodulation protocols prevent the emergence of high antibody titers to ERT. Besides survival, decreased ERT efficacy appeared after the age of 6 years, with a progressive decline in motor and pulmonary functions for most survivors. CONCLUSIONS: This study reports the long-term follow-up of one of the largest cohorts of classical IOPD patients and demonstrates high long-term mortality and morbidity rates with a secondary decline in muscular and respiratory functions. This decreased efficacy seems to be multifactorial, highlighting the importance of developing new therapeutic approaches targeting various aspects of pathogenesis.

Enasidenib treatment in two individuals with D-2-hydroxyglutaric aciduria carrying a germline IDH2 mutation.

D-2-hydroxyglutaric aciduria type II (D2HGA2) is a severe inborn disorder of metabolism caused by heterozygous R140 mutations in the IDH2 (isocitrate dehydrogenase 2) gene. Here we report the results of treatment of two children with D2HGA2, one of whom exhibited severe dilated cardiomyopathy, with the selective mutant IDH2 enzyme inhibitor enasidenib. In both children, enasidenib treatment led to normalization of D-2-hydroxyglutarate (D-2-HG) concentrations in body fluids. At doses of 50 mg and 60 mg per day, no side effects were observed, except for asymptomatic hyperbilirubinemia. For the child with cardiomyopathy, chronic D-2-HG inhibition was associated with improved cardiac function, and for both children, therapy was associated with improved daily functioning, global motility and social interactions. Treatment of the child with cardiomyopathy led to therapy-coordinated changes in serum phospholipid levels, which were partly recapitulated in cultured fibroblasts, associated with complex effects on lipid and redox-related gene pathways. These findings indicate that targeted inhibition of a mutant enzyme can partly reverse the pathology of a chronic neurometabolic genetic disorder.

JAK Inhibition in Aicardi-Goutières Syndrome: a Monocentric Multidisciplinary Real-World Approach Study.

The paradigm type I interferonopathy Aicardi-Goutières syndrome (AGS) is most typically characterized by severe neurological involvement. AGS is considered an immune-mediated disease, poorly responsive to conventional immunosuppression. Premised on a chronic enhancement of type I interferon signaling, JAK1/2 inhibition has been trialed in AGS, with clear improvements in cutaneous and systemic disease manifestations. Contrastingly, treatment efficacy at the level of the neurological system has been less conclusive. Here, we report our real-word approach study of JAK1/2 inhibition in 11 patients with AGS, providing extensive assessments of clinical and radiological status; interferon signaling, including in cerebrospinal fluid (CSF); and drug concentrations in blood and CSF. Over a median follow-up of 17 months, we observed a clear benefit of JAK1/2 inhibition on certain systemic features of AGS, and reproduced results reported using the AGS neurologic severity scale. In contrast, there was no change in other scales assessing neurological status; using the caregiver scale, only patient comfort, but no other domain of everyday-life care, was improved. Serious bacterial infections occurred in 4 out of the 11 patients. Overall, our data lead us to conclude that other approaches to treatment are urgently required for the neurologic features of AGS. We suggest that earlier diagnosis and adequate central nervous system penetration likely remain the major factors determining the efficacy of therapy in preventing irreversible brain damage, implying the importance of early and rapid genetic testing and the consideration of intrathecal drug delivery.

Systemic corticosteroids for the treatment of acute episodes of rhabdomyolysis in lipin-1-deficient patients.

Mutations in the LPIN1 gene constitute a major cause of severe rhabdomyolysis (RM). The TLR9 activation prompted us to treat patients with corticosteroids in acute conditions. In patients with LPIN1 mutations, RM and at-risk situations that can trigger RM have been treated in a uniform manner. Since 2015, these patients have also received intravenous corticosteroids. We retrospectively compared data on hospital stays by corticosteroid-treated patients vs. patients not treated with corticosteroids. Nineteen patients were hospitalized. The median number of admissions per patient was 21 overall and did not differ when comparing the 10 corticosteroid-treated patients with the 9 patients not treated with corticosteroids. Four patients in the non-corticosteroid group died during a RM (mean age at death: 5.6 years). There were no deaths in the corticosteroid group. The two groups did not differ significantly in the number of RM episodes. However, for the six patients who had RM and occasionally been treated with corticosteroids, the median number of RM episodes was significantly lower when intravenous steroids had been administered. The peak plasma creatine kinase level and the area under the curve were or tended to be higher in patients treated with corticosteroids-even after the exclusion of deceased patients or focusing on the period after 2015. The median length of stay (10 days overall) was significantly longer for corticosteroid-treated patients but was similar after the exclusion of deceased patients. The absence of deaths and the higher severity of RM observed among corticosteroid-treated patients could suggest that corticotherapy is associated with greater survival.

Long term follow-up after haematopoietic stem cell transplantation for mucopolysaccharidosis type I-H: a retrospective study of 51 patients.

Mucopolysaccharidosis type I-H (MPS I-H) is a rare lysosomal storage disorder caused by α-L-Iduronidase deficiency. Early haematopoietic stem cell transplantation (HSCT) is the sole available therapeutic option to preserve neurocognitive functions. We report long-term follow-up (median 9 years, interquartile range 8-16.5) for 51 MPS I-H patients who underwent HSCT between 1986 and 2018 in France. 4 patients died from complications of HSCT and one from disease progression. Complete chimerism and normal α-L-Iduronidase activity were obtained in 84% and 71% of patients respectively. No difference of outcomes was observed between bone marrow and cord blood stem cell sources. All patients acquired independent walking and 91% and 78% acquired intelligible language or reading and writing. Intelligence Quotient evaluation (n = 23) showed that 69% had IQ ≥ 70 at last follow-up. 58% of patients had normal or remedial schooling and 62% of the 13 adults had good socio-professional insertion. Skeletal dysplasia as well as vision and hearing impairments progressed despite HSCT, with significant disability. These results provide a long-term assessment of HSCT efficacy in MPS I-H and could be useful in the evaluation of novel promising treatments such as gene therapy.

Individual and Family Determinants for Quality of Life in Parents of Children with Inborn Errors of Metabolism Requiring a Restricted Diet: A Multilevel Analysis Approach.

OBJECTIVE: The objective of this study was to compare the quality of life (QoL) for parents of children with inborn errors of metabolism (IEMs) requiring a restricted diet with French population norms and investigate parental QoL determinants. STUDY DESIGN: This cross-sectional study included mothers and/or fathers of children < 18 years of age affected by IEMs requiring a restricted diet (except phenylketonuria) from January 2015 to December 2017. Parents' QoL was assessed using the World Health Organization Quality of Life BREF questionnaire and compared with age- and sex-matched reference values from the French general population. Linear mixed models were used to examine the effects of demographic, socioeconomic, disease-related, and psychocognitive factors on parental QoL, according to a 2-level regression model considering individuals (parents) nested within families. RESULTS: Of the 1156 parents invited to participate, 785 (68%) were included. Compared with the general population, parents of children with IEMs requiring a restricted diet reported a lower QoL in physical and social relationship domains but a higher QoL in the psychological domain. In the multivariate analysis, characteristics associated with poorer parental QoL included both parent-related factors (being a father, older age, more educated parent, nonworking parent, greater anxiety, seeking more social support, and using less positive thinking and problem-solving coping strategies) and family-related factors (disease complications, increased number of hospital medical providers, child's younger age, single-parent family, and lower family material wealth). CONCLUSION: Parents of children with IEMs requiring a restricted diet reported poorer QoL in physical and social relationship domains than population norms. Psychocognitive factors, beyond disease-specific and family-related characteristics, were the most important determinants influencing parental QoL and may represent essential aspects for interventions. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: NCT02552784.